Endpoints

Every route, from the OpenAPI document the server is checked against.

Method	Path	Does	Scope
POST	/api/v1/listings	Enter a listing once	`listings:write`
GET	/api/v1/listings/{key}	Read a listing	`listings:read or feed:read`
PATCH	/api/v1/listings/{key}	Change a listing	`listings:write`
GET	/api/v1/listings/{key}/deliveries	Where a listing is live	`listings:read`
POST	/api/v1/listings/{key}/media/uploads	Start a photo upload	`listings:write`
GET	/api/v1/listings/{key}/media	A listing's photos	`listings:read`
POST	/api/v1/listings/{key}/media	Finish a photo upload	`listings:write`
PATCH	/api/v1/listings/{key}/media	Reorder photos	`listings:write`
DELETE	/api/v1/listings/{key}/media/{mediaKey}	Remove a photo	`listings:write`
GET	/api/v1/export	Export everything your brokerage owns	`listings:read`
GET	/api/v1/conflicts	Same address as another brokerage	`listings:read`
POST	/api/v1/webhooks	Subscribe to listing changes	`webhooks:manage`
GET	/api/v1/webhooks	Your subscriptions	`webhooks:manage`
DELETE	/api/v1/webhooks/{id}	Unsubscribe	`webhooks:manage`
POST	/api/v1/keys/rotate	Rotate this key	`listings:write or listings:read or feed:read or webhooks:manage`
GET	/api/reso	Service document	`feed:read`
GET	/api/reso/$metadata	Data model	`feed:read`
GET	/api/reso/Lookup	Lookup values	`feed:read`
POST	/api/reso/Property	Enter a listing in RESO fields	`listings:write`
GET	/api/reso/Property	Search the feed	`feed:read`
PATCH	/api/reso/Property('{key}')	Change a listing in RESO fields	`listings:write`
GET	/api/reso/Property/{key}	One listing from the feed	`feed:read`
GET	/api/reso/Media	Photos in the feed	`feed:read`

Method: POST
Path: /api/v1/listings
Does: Enter a listing once
Scope: listings:write

Method: GET
Path: /api/v1/listings/{key}
Does: Read a listing
Scope: listings:read or feed:read

Method: PATCH
Path: /api/v1/listings/{key}
Does: Change a listing
Scope: listings:write

Method: GET
Path: /api/v1/listings/{key}/deliveries
Does: Where a listing is live
Scope: listings:read

Method: POST
Path: /api/v1/listings/{key}/media/uploads
Does: Start a photo upload
Scope: listings:write

Method: GET
Path: /api/v1/listings/{key}/media
Does: A listing's photos
Scope: listings:read

Method: POST
Path: /api/v1/listings/{key}/media
Does: Finish a photo upload
Scope: listings:write

Method: PATCH
Path: /api/v1/listings/{key}/media
Does: Reorder photos
Scope: listings:write

Method: DELETE
Path: /api/v1/listings/{key}/media/{mediaKey}
Does: Remove a photo
Scope: listings:write

Method: GET
Path: /api/v1/export
Does: Export everything your brokerage owns
Scope: listings:read

Method: GET
Path: /api/v1/conflicts
Does: Same address as another brokerage
Scope: listings:read

Method: POST
Path: /api/v1/webhooks
Does: Subscribe to listing changes
Scope: webhooks:manage

Method: GET
Path: /api/v1/webhooks
Does: Your subscriptions
Scope: webhooks:manage

Method: DELETE
Path: /api/v1/webhooks/{id}
Does: Unsubscribe
Scope: webhooks:manage

Method: POST
Path: /api/v1/keys/rotate
Does: Rotate this key
Scope: listings:write or listings:read or feed:read or webhooks:manage

Method: GET
Path: /api/reso
Does: Service document
Scope: feed:read

Method: GET
Path: /api/reso/$metadata
Does: Data model
Scope: feed:read

Method: GET
Path: /api/reso/Lookup
Does: Lookup values
Scope: feed:read

Method: POST
Path: /api/reso/Property
Does: Enter a listing in RESO fields
Scope: listings:write

Method: GET
Path: /api/reso/Property
Does: Search the feed
Scope: feed:read

Method: PATCH
Path: /api/reso/Property('{key}')
Does: Change a listing in RESO fields
Scope: listings:write

Method: GET
Path: /api/reso/Property/{key}
Does: One listing from the feed
Scope: feed:read

Method: GET
Path: /api/reso/Media
Does: Photos in the feed
Scope: feed:read

POST/api/v1/listings

Enter a listing once

Member brokerages only. The caller's organization becomes the listing brokerage and owner. The listing is planned to every destination in its market under the seller's visibility choice and each MLS's current rules, and the history starts with three fingerprinted lines. A listing at the address of another brokerage's active listing is entered and flagged: both owners get a history line (which never names the other brokerage or listing) and listing.conflict, and the pair shows under /api/v1/conflicts until the platform operator decides it.

Auth: a Bearer key with listings:write.

Parameters

Idempotency-Keystring in header: ^[\x21-\x7E]{1,200}$; Optional. Repeats with the same key and body replay the first response for 24 hours; the same key with a different body is refused.

Body

streetstringRequired: 1 to 120 chars; Street address. Not blank, no < or >.
citystringRequired: Austin · Charlotte · Phoenix · Tampa; Pilot market.
statestringRequired: TX · NC · AZ · FL; Two letter state; must match the city.
zipstringRequired: ^\d{5}$; 5 digit ZIP.
priceintegerRequired: 1 to 1,000,000,000; List price in whole dollars.
bedsintegerRequired: 0 to 50; Bedrooms.
bathsnumberRequired: 0 to 50, steps of 0.5; Bathrooms, in halves.
sqftintegerRequired: 0 to 100,000; Living area in square feet.
lotAcresnumber: 0 to 100,000, steps of 0.01; Lot size in acres.
yearBuiltinteger: 1700 to 2030; Year built.
propertyTypestringRequired: Single Family · Townhouse · Condominium · Multi Family; Property sub type.
remarksstringRequired: 1 to 2000 chars; Public remarks. Not blank, no < or >.
agentstringRequired: 1 to 80 chars; Listing agent's name. Not blank, no < or >.
sellerstringRequired: 1 to 120 chars; Seller's name. Seen only by the owner. Not blank, no < or >.
visibilitystringRequired: public · coming_soon · members_only; The seller's choice: public (the usual one), coming_soon or members_only.
goLiveDatestring: YYYY-MM-DD; Required for coming_soon. Not in the past.
listingAgreementAtstringRequired: YYYY-MM-DD; The day the listing agreement was signed. Within the last year, not after tomorrow (UTC).

Request

curl -X POST "https://listonce.io/api/v1/listings" \
  -H "Authorization: Bearer $LISTONCE_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "street": "88 Cedar Bluff Dr",
    "city": "Austin",
    "state": "TX",
    "zip": "78704",
    "price": 625000,
    "beds": 3,
    "baths": 2.5,
    "sqft": 1960,
    "lotAcres": 0.18,
    "yearBuilt": 2004,
    "propertyType": "Single Family",
    "remarks": "Quiet street, open kitchen and a covered patio facing the greenbelt.",
    "agent": "Rowan Ellis",
    "seller": "A. and T. Monroe",
    "visibility": "members_only",
    "listingAgreementAt": "2026-10-26"
  }'

Response 201

{
  "street": "88 Cedar Bluff Dr",
  "city": "Austin",
  "state": "TX",
  "zip": "78704",
  "price": 625000,
  "beds": 3,
  "baths": 2.5,
  "sqft": 1960,
  "lotAcres": 0.18,
  "yearBuilt": 2004,
  "propertyType": "Single Family",
  "remarks": "Quiet street, open kitchen and a covered patio facing the greenbelt.",
  "agent": "Rowan Ellis",
  "seller": "A. and T. Monroe",
  "visibility": "members_only",
  "listingAgreementAt": "2026-10-26",
  "id": "OL-RCGZQ4",
  "addressKey": "88|CEDAR BLUFF DR||AUSTIN|TX|78704",
  "brokerage": "Harbor & Pine Realty",
  "source": "api",
  "status": "Active",
  "returns": {},
  "photos": [],
  "sellerConsentAt": "2026-10-26T15:04:12.318Z",
  "createdAt": "2026-10-26T15:04:12.318Z",
  "updatedAt": "2026-10-26T15:04:12.318Z",
  "tint": 0,
  "deliveries": [
    {
      "destId": "mls-austin",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "portal-a",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "portal-b",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "portal-c",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "net-members",
      "state": "delivered",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "data-appraisal",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "data-records",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    }
  ],
  "history": [
    {
      "at": "2026-10-26T15:04:12.318Z",
      "who": "Rowan Ellis",
      "what": "Seller chose members only",
      "hash": "0350a77c66e2d3"
    },
    {
      "at": "2026-10-26T15:04:12.318Z",
      "who": "Rowan Ellis",
      "what": "Listing entered once",
      "hash": "1cde064c84ab14"
    },
    {
      "at": "2026-10-26T15:04:12.318Z",
      "who": "ListOnce",
      "what": "Sent to 1 of 7 destinations",
      "hash": "1d54774e9f1ec6"
    }
  ],
  "historyIntact": true,
  "lateDays": 0,
  "remarkFlags": []
}

Status	When
201	Created. The owner's view of the listing.
400	A field failed validation, a field is unknown, or the body is not a JSON object.
401	No key, a malformed key, or a revoked one.
403	The key lacks listings:write, or its organization is not a member brokerage.
409	The brokerage already has an active listing (Coming Soon, Active or Pending) at this address: existingKey names it. Update that listing, or withdraw it before listing again. Or a request with this Idempotency-Key is still running.
413	Body over 16,384 bytes.
422	This Idempotency-Key was used for a different body.
429	Over this key's requests per minute.

Status: 201
When: Created. The owner's view of the listing.

Status: 400
When: A field failed validation, a field is unknown, or the body is not a JSON object.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks listings:write, or its organization is not a member brokerage.

Status: 409
When: The brokerage already has an active listing (Coming Soon, Active or Pending) at this address: existingKey names it. Update that listing, or withdraw it before listing again. Or a request with this Idempotency-Key is still running.

Status: 413
When: Body over 16,384 bytes.

Status: 422
When: This Idempotency-Key was used for a different body.

Status: 429
When: Over this key's requests per minute.

GET/api/v1/listings/{key}

Read a listing

The owner (with listings:read) gets the full listing with its deliveries and history. Another member brokerage with listings:read gets a members only listing as its own marked copy (an alias for the key and photo URLs issued to it), and every read is logged. Any other key with feed:read gets the RESO record, and only while the listing may be publicly marketed: members only and coming soon listings answer 404.

Auth: a Bearer key with listings:read or feed:read.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.

Request

curl "https://listonce.io/api/v1/listings/OL-4K7Q2M" \
  -H "Authorization: Bearer ol_demo_7f3a9c2e5b1d4086"

Response 200

{
  "@odata.context": "https://listonce.io/api/reso/$metadata#Property/$entity",
  "ListingKey": "OL-4K7Q2M",
  "OriginatingSystemName": "ListOnce",
  "StandardStatus": "Active",
  "ListPrice": 589000,
  "ClosePrice": null,
  "UnparsedAddress": "1418 Larkspur Way, Austin, TX 78745",
  "City": "Austin",
  "StateOrProvince": "TX",
  "PostalCode": "78745",
  "PropertyType": "Residential",
  "PropertySubType": "Single Family Residence",
  "BedroomsTotal": 3,
  "BathroomsTotalInteger": 2,
  "BathroomsFull": 2,
  "BathroomsHalf": 0,
  "LivingArea": 1840,
  "LivingAreaUnits": "Square Feet",
  "LotSizeAcres": 0.21,
  "YearBuilt": 1998,
  "PublicRemarks": "Shaded corner lot, updated kitchen, two living areas and a deep backyard with mature oaks.",
  "ListAgentFullName": "Dana Whitfield",
  "ListOfficeName": "Harbor & Pine Realty",
  "ListingContractDate": "2026-10-24",
  "OnMarketDate": "2026-10-24",
  "ModificationTimestamp": "2026-10-24T21:03:00.000Z",
  "LO_SellerVisibilityChoice": "public",
  "LO_SellerChoiceRecordedAt": "2026-10-24T10:20:00.000Z"
}

Status	When
200	The owner's view, or the RESO record for a feed reader.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such listing, or not one this key may read.
429	Over this key's requests per minute.

Status: 200
When: The owner's view, or the RESO record for a feed reader.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such listing, or not one this key may read.

Status: 429
When: Over this key's requests per minute.

PATCH/api/v1/listings/{key}

Change a listing

Owner only. Send just the fields that change; null clears lotAcres or yearBuilt. A new visibility is a new seller choice: the choice time resets, and switching to or from coming soon moves the status between Coming Soon and Active. soldPrice is allowed only on a Closed listing; leaving Closed drops it. resend true clears MLS send backs and resends to every destination. Every destination is re-planned; one keeps its time unless its outcome changed.

Auth: a Bearer key with listings:write.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.

Body

streetstring: 1 to 120 chars; Street address. Not blank, no < or >.
citystring: Austin · Charlotte · Phoenix · Tampa; Pilot market.
statestring: TX · NC · AZ · FL; Two letter state; must match the city.
zipstring: ^\d{5}$; 5 digit ZIP.
priceinteger: 1 to 1,000,000,000; List price in whole dollars.
bedsinteger: 0 to 50; Bedrooms.
bathsnumber: 0 to 50, steps of 0.5; Bathrooms, in halves.
sqftinteger: 0 to 100,000; Living area in square feet.
lotAcresnumber or null: 0 to 100,000, steps of 0.01; Lot size in acres. null clears it.
yearBuiltinteger or null: 1700 to 2030; Year built. null clears it.
propertyTypestring: Single Family · Townhouse · Condominium · Multi Family; Property sub type.
remarksstring: 1 to 2000 chars; Public remarks. Not blank, no < or >.
statusstring: Coming Soon · Active · Pending · Closed · Withdrawn; New status.
visibilitystring: public · coming_soon · members_only; A new seller choice.
goLiveDatestring: YYYY-MM-DD; Go live date for coming soon. Not in the past.
soldPriceinteger: 1 to 1,000,000,000; Sold price; only when the status is Closed.
resendboolean: Clear send backs and resend everywhere.

Request

curl -X PATCH "https://listonce.io/api/v1/listings/OL-4K7Q2M" \
  -H "Authorization: Bearer $LISTONCE_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "price": 615000,
    "status": "Pending"
  }'

Response 200

{
  "street": "88 Cedar Bluff Dr",
  "city": "Austin",
  "state": "TX",
  "zip": "78704",
  "price": 615000,
  "beds": 3,
  "baths": 2.5,
  "sqft": 1960,
  "lotAcres": 0.18,
  "yearBuilt": 2004,
  "propertyType": "Single Family",
  "remarks": "Quiet street, open kitchen and a covered patio facing the greenbelt.",
  "agent": "Rowan Ellis",
  "seller": "A. and T. Monroe",
  "visibility": "members_only",
  "listingAgreementAt": "2026-10-26",
  "id": "OL-RCGZQ4",
  "addressKey": "88|CEDAR BLUFF DR||AUSTIN|TX|78704",
  "brokerage": "Harbor & Pine Realty",
  "source": "api",
  "status": "Pending",
  "returns": {},
  "photos": [],
  "sellerConsentAt": "2026-10-26T15:04:12.318Z",
  "createdAt": "2026-10-26T15:04:12.318Z",
  "updatedAt": "2026-10-26T16:40:05.902Z",
  "tint": 0,
  "deliveries": [
    {
      "destId": "mls-austin",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "portal-a",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "portal-b",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "portal-c",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "net-members",
      "state": "delivered",
      "at": "2026-10-26T16:40:05.902Z",
      "note": "Shown as pending"
    },
    {
      "destId": "data-appraisal",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    },
    {
      "destId": "data-records",
      "state": "held",
      "note": "Seller chose members only",
      "at": "2026-10-26T15:04:12.318Z"
    }
  ],
  "history": [
    {
      "at": "2026-10-26T15:04:12.318Z",
      "who": "Rowan Ellis",
      "what": "Seller chose members only",
      "hash": "0350a77c66e2d3"
    },
    {
      "at": "2026-10-26T15:04:12.318Z",
      "who": "Rowan Ellis",
      "what": "Listing entered once",
      "hash": "1cde064c84ab14"
    },
    {
      "at": "2026-10-26T15:04:12.318Z",
      "who": "ListOnce",
      "what": "Sent to 1 of 7 destinations",
      "hash": "1d54774e9f1ec6"
    },
    {
      "at": "2026-10-26T16:40:05.902Z",
      "who": "Harbor & Pine Realty",
      "what": "Price changed to $615,000; Status changed to Pending",
      "hash": "13d47d05eda81d"
    },
    {
      "at": "2026-10-26T16:40:05.902Z",
      "who": "ListOnce",
      "what": "Sent to 1 of 7 destinations",
      "hash": "1b9856cf24d71e"
    }
  ],
  "historyIntact": true,
  "lateDays": 0,
  "remarkFlags": []
}

Status	When
200	The owner's view after the change.
400	A field failed validation, a cross field rule failed, the body was empty, or nothing would change.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such listing owned by this key's brokerage.
409	The brokerage already has an active listing (Coming Soon, Active or Pending) at this address: existingKey names it. Update that listing, or withdraw it before listing again. Or the listing changed while this request ran: read it again and retry. Checked when the address changes or the listing comes back to market.
413	Body over 16,384 bytes.
429	Over this key's requests per minute.

Status: 200
When: The owner's view after the change.

Status: 400
When: A field failed validation, a cross field rule failed, the body was empty, or nothing would change.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such listing owned by this key's brokerage.

Status: 409
When: The brokerage already has an active listing (Coming Soon, Active or Pending) at this address: existingKey names it. Update that listing, or withdraw it before listing again. Or the listing changed while this request ran: read it again and retry. Checked when the address changes or the listing comes back to market.

Status: 413
When: Body over 16,384 bytes.

Status: 429
When: Over this key's requests per minute.

GET/api/v1/listings/{key}/deliveries

Where a listing is live

Owner only: one line per destination in the listing's market with its outcome and any note.

Auth: a Bearer key with listings:read.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.

Request

curl "https://listonce.io/api/v1/listings/OL-4K7Q2M/deliveries" \
  -H "Authorization: Bearer $LISTONCE_KEY"

Response 200

{
  "listingKey": "OL-4K7Q2M",
  "value": [
    {
      "destId": "mls-austin",
      "state": "delivered",
      "at": "2026-10-24T11:02:00.000Z",
      "destination": "Demo MLS Austin",
      "kind": "mls"
    },
    {
      "destId": "net-members",
      "state": "delivered",
      "at": "2026-10-24T11:02:00.000Z",
      "destination": "Member brokerages",
      "kind": "network"
    },
    {
      "destId": "portal-a",
      "state": "delivered",
      "at": "2026-10-24T11:02:00.000Z",
      "destination": "Demo Portal A",
      "kind": "portal"
    }
  ]
}

Status	When
200	Deliveries, sorted by destination id.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such listing owned by this key's brokerage.
429	Over this key's requests per minute.

Status: 200
When: Deliveries, sorted by destination id.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such listing owned by this key's brokerage.

Status: 429
When: Over this key's requests per minute.

POST/api/v1/listings/{key}/media/uploads

Start a photo upload

Owner only, no body. Answers a one time URL: PUT the photo there as the raw body with its Content-Type (image/jpeg, image/png or image/webp, at most 8 MB), within two hours, then finish with POST /media and the uploadId. A listing holds at most 25 photos.

Auth: a Bearer key with listings:write.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.

Request

curl -X POST "https://listonce.io/api/v1/listings/OL-4K7Q2M/media/uploads" \
  -H "Authorization: Bearer $LISTONCE_KEY"

Response 201

{
  "uploadId": "5b0c1f9e-2d4a-4c1e-9a77-1f3e2b8d6c40",
  "uploadUrl": "https://storage.example.com/object/upload/sign/listing-photos/uploads/OL-4K7Q2M.5b0c1f9e-2d4a-4c1e-9a77-1f3e2b8d6c40?token=eyJhbGciOi",
  "method": "PUT",
  "expiresAt": "2026-10-26T17:20:41.000Z",
  "maxBytes": 8388608,
  "contentTypes": [
    "image/jpeg",
    "image/png",
    "image/webp"
  ]
}

Status	When
201	Where to PUT the photo.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such listing owned by this key's brokerage.
409	The listing already has 25 photos.
429	Over this key's requests per minute.

Status: 201
When: Where to PUT the photo.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such listing owned by this key's brokerage.

Status: 409
When: The listing already has 25 photos.

Status: 429
When: Over this key's requests per minute.

GET/api/v1/listings/{key}/media

A listing's photos

Owner only. The photos in order; the first is the preferred one. MediaURL is a signed link on this host that lasts about 12 hours: store the photo, not the link.

Auth: a Bearer key with listings:read.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.

Request

curl "https://listonce.io/api/v1/listings/OL-4K7Q2M/media" \
  -H "Authorization: Bearer $LISTONCE_KEY"

Response 200

{
  "listingKey": "OL-4K7Q2M",
  "value": [
    {
      "MediaKey": "OLP-7RQ2KD9XWM",
      "ResourceRecordKey": "OL-4K7Q2M",
      "ResourceName": "Property",
      "MediaCategory": "Photo",
      "MediaURL": "https://listonce.io/m/OLP-7RQ2KD9XWM.jpg?a=o&e=1793095200&s=Jp2c1v9yQkXo3H7bTn0aLw5rUe8sDf4gZi6mCxVhKqY",
      "Order": 0,
      "ImageWidth": 2560,
      "ImageHeight": 1707,
      "PreferredPhotoYN": true,
      "ModificationTimestamp": "2026-10-26T15:20:41.000Z"
    },
    {
      "MediaKey": "OLP-C4HNV8TZ3P",
      "ResourceRecordKey": "OL-4K7Q2M",
      "ResourceName": "Property",
      "MediaCategory": "Photo",
      "MediaURL": "https://listonce.io/m/OLP-C4HNV8TZ3P.jpg?a=o&e=1793095200&s=Jp2c1v9yQkXo3H7bTn0aLw5rUe8sDf4gZi6mCxVhKqY",
      "Order": 1,
      "ImageWidth": 2560,
      "ImageHeight": 1707,
      "PreferredPhotoYN": false,
      "ModificationTimestamp": "2026-10-26T15:20:41.000Z"
    }
  ]
}

Status	When
200	Photos, in order.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such listing owned by this key's brokerage.
429	Over this key's requests per minute.

Status: 200
When: Photos, in order.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such listing owned by this key's brokerage.

Status: 429
When: Over this key's requests per minute.

POST/api/v1/listings/{key}/media

Finish a photo upload

Owner only. Checks the uploaded file is the JPEG, PNG or WebP its first bytes say, turns it upright, scales it to at most 2560 pixels on the long side and stores it as a JPEG, which drops every metadata block (GPS location included). It becomes the last photo, or the preferred one if it is the first. Adds a history line and sends listing.updated. Finishing the same uploadId again answers the same photo.

Auth: a Bearer key with listings:write.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.

Body

uploadIdstringRequired: From the upload step.

Request

curl -X POST "https://listonce.io/api/v1/listings/OL-4K7Q2M/media" \
  -H "Authorization: Bearer $LISTONCE_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "uploadId": "5b0c1f9e-2d4a-4c1e-9a77-1f3e2b8d6c40"
  }'

Response 201

{
  "MediaKey": "OLP-C4HNV8TZ3P",
  "ResourceRecordKey": "OL-4K7Q2M",
  "ResourceName": "Property",
  "MediaCategory": "Photo",
  "MediaURL": "https://listonce.io/m/OLP-C4HNV8TZ3P.jpg?a=o&e=1793095200&s=Jp2c1v9yQkXo3H7bTn0aLw5rUe8sDf4gZi6mCxVhKqY",
  "Order": 1,
  "ImageWidth": 2560,
  "ImageHeight": 1707,
  "PreferredPhotoYN": false,
  "ModificationTimestamp": "2026-10-26T15:20:41.000Z"
}

Status	When
201	The photo.
400	Unknown field, or uploadId is not an upload id.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such listing owned by this key's brokerage, or nothing was PUT to the upload URL.
409	The listing has 25 photos, or it changed while this request ran.
413	The body is over 16,384 bytes, or the photo over 8 MB.
415	The file is not a JPEG, PNG or WebP.
422	The file is damaged or over 50 megapixels.
429	Over this key's requests per minute.

Status: 201
When: The photo.

Status: 400
When: Unknown field, or uploadId is not an upload id.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such listing owned by this key's brokerage, or nothing was PUT to the upload URL.

Status: 409
When: The listing has 25 photos, or it changed while this request ran.

Status: 413
When: The body is over 16,384 bytes, or the photo over 8 MB.

Status: 415
When: The file is not a JPEG, PNG or WebP.

Status: 422
When: The file is damaged or over 50 megapixels.

Status: 429
When: Over this key's requests per minute.

PATCH/api/v1/listings/{key}/media

Reorder photos

Owner only. order lists every MediaKey of the listing once; the first becomes the preferred photo. Adds a history line and sends listing.updated.

Auth: a Bearer key with listings:write.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.

Body

orderarray of stringRequired: Every MediaKey of the listing once, first is preferred. 1 to 25.

Request

curl -X PATCH "https://listonce.io/api/v1/listings/OL-4K7Q2M/media" \
  -H "Authorization: Bearer $LISTONCE_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "order": [
      "OLP-C4HNV8TZ3P",
      "OLP-7RQ2KD9XWM"
    ]
  }'

Response 200

{
  "listingKey": "OL-4K7Q2M",
  "value": [
    {
      "MediaKey": "OLP-C4HNV8TZ3P",
      "ResourceRecordKey": "OL-4K7Q2M",
      "ResourceName": "Property",
      "MediaCategory": "Photo",
      "MediaURL": "https://listonce.io/m/OLP-C4HNV8TZ3P.jpg?a=o&e=1793095200&s=Jp2c1v9yQkXo3H7bTn0aLw5rUe8sDf4gZi6mCxVhKqY",
      "Order": 0,
      "ImageWidth": 2560,
      "ImageHeight": 1707,
      "PreferredPhotoYN": true,
      "ModificationTimestamp": "2026-10-26T15:20:41.000Z"
    },
    {
      "MediaKey": "OLP-7RQ2KD9XWM",
      "ResourceRecordKey": "OL-4K7Q2M",
      "ResourceName": "Property",
      "MediaCategory": "Photo",
      "MediaURL": "https://listonce.io/m/OLP-7RQ2KD9XWM.jpg?a=o&e=1793095200&s=Jp2c1v9yQkXo3H7bTn0aLw5rUe8sDf4gZi6mCxVhKqY",
      "Order": 1,
      "ImageWidth": 2560,
      "ImageHeight": 1707,
      "PreferredPhotoYN": false,
      "ModificationTimestamp": "2026-10-26T15:20:41.000Z"
    }
  ]
}

Status	When
200	The photos in their new order.
400	order is not every MediaKey of the listing once, or nothing changed.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such listing owned by this key's brokerage.
409	The listing changed while this request ran. Retry.
413	Body over 16,384 bytes.
429	Over this key's requests per minute.

Status: 200
When: The photos in their new order.

Status: 400
When: order is not every MediaKey of the listing once, or nothing changed.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such listing owned by this key's brokerage.

Status: 409
When: The listing changed while this request ran. Retry.

Status: 413
When: Body over 16,384 bytes.

Status: 429
When: Over this key's requests per minute.

DELETE/api/v1/listings/{key}/media/{mediaKey}

Remove a photo

Owner only. Deletes the stored file; the next photo moves up, and if this was the preferred one, the new first photo is. Adds a history line and sends listing.updated.

Auth: a Bearer key with listings:write.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.
mediaKeystring in pathRequired: ^OLP-[A-HJ-NP-Z2-9]{10}$; The photo's MediaKey.

Request

curl -X DELETE "https://listonce.io/api/v1/listings/OL-4K7Q2M/media/OLP-7RQ2KD9XWM" \
  -H "Authorization: Bearer $LISTONCE_KEY"

Response 204

Removed.

Status	When
204	Removed.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such listing owned by this key's brokerage, or no such photo on it.
409	The listing changed while this request ran. Retry.
429	Over this key's requests per minute.

Status: 204
When: Removed.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such listing owned by this key's brokerage, or no such photo on it.

Status: 409
When: The listing changed while this request ran. Retry.

Status: 429
When: Over this key's requests per minute.

GET/api/v1/export

Export everything your brokerage owns

Member brokerages only. Every listing the caller's brokerage owns, as the owner sees them: deliveries and whole history. Sorted by key, at most 50 a page; follow nextLink until it is absent. Signed-in admins can download the same as one JSON lines file from Settings.

Auth: a Bearer key with listings:read.

Parameters

afterstring in query: ^OL-[A-Z0-9]{6}$; Start after this listing key. nextLink sets it.

Request

curl "https://listonce.io/api/v1/export" \
  -H "Authorization: Bearer $LISTONCE_KEY"

Response 200

{
  "organization": "Harbor & Pine Realty",
  "exportedAt": "2026-10-26T16:40:05.902Z",
  "value": [
    {
      "street": "88 Cedar Bluff Dr",
      "city": "Austin",
      "state": "TX",
      "zip": "78704",
      "price": 625000,
      "beds": 3,
      "baths": 2.5,
      "sqft": 1960,
      "lotAcres": 0.18,
      "yearBuilt": 2004,
      "propertyType": "Single Family",
      "remarks": "Quiet street, open kitchen and a covered patio facing the greenbelt.",
      "agent": "Rowan Ellis",
      "seller": "A. and T. Monroe",
      "visibility": "members_only",
      "listingAgreementAt": "2026-10-26",
      "id": "OL-RCGZQ4",
      "addressKey": "88|CEDAR BLUFF DR||AUSTIN|TX|78704",
      "brokerage": "Harbor & Pine Realty",
      "source": "api",
      "status": "Active",
      "returns": {},
      "photos": [],
      "sellerConsentAt": "2026-10-26T15:04:12.318Z",
      "createdAt": "2026-10-26T15:04:12.318Z",
      "updatedAt": "2026-10-26T15:04:12.318Z",
      "tint": 0,
      "deliveries": [
        {
          "destId": "mls-austin",
          "state": "held",
          "note": "Seller chose members only",
          "at": "2026-10-26T15:04:12.318Z"
        },
        {
          "destId": "portal-a",
          "state": "held",
          "note": "Seller chose members only",
          "at": "2026-10-26T15:04:12.318Z"
        },
        {
          "destId": "portal-b",
          "state": "held",
          "note": "Seller chose members only",
          "at": "2026-10-26T15:04:12.318Z"
        },
        {
          "destId": "portal-c",
          "state": "held",
          "note": "Seller chose members only",
          "at": "2026-10-26T15:04:12.318Z"
        },
        {
          "destId": "net-members",
          "state": "delivered",
          "at": "2026-10-26T15:04:12.318Z"
        },
        {
          "destId": "data-appraisal",
          "state": "held",
          "note": "Seller chose members only",
          "at": "2026-10-26T15:04:12.318Z"
        },
        {
          "destId": "data-records",
          "state": "held",
          "note": "Seller chose members only",
          "at": "2026-10-26T15:04:12.318Z"
        }
      ],
      "history": [
        {
          "at": "2026-10-26T15:04:12.318Z",
          "who": "Rowan Ellis",
          "what": "Seller chose members only",
          "hash": "0350a77c66e2d3"
        },
        {
          "at": "2026-10-26T15:04:12.318Z",
          "who": "Rowan Ellis",
          "what": "Listing entered once",
          "hash": "1cde064c84ab14"
        },
        {
          "at": "2026-10-26T15:04:12.318Z",
          "who": "ListOnce",
          "what": "Sent to 1 of 7 destinations",
          "hash": "1d54774e9f1ec6"
        }
      ],
      "historyIntact": true,
      "lateDays": 0,
      "remarkFlags": []
    }
  ],
  "nextLink": "https://listonce.io/api/v1/export?after=OL-RCGZQ4"
}

Status	When
200	One page.
400	after is not a listing key.
401	No key, a malformed key, or a revoked one.
403	The key lacks listings:read, or its organization is not a member brokerage.
429	Over this key's requests per minute.

Status: 200
When: One page.

Status: 400
When: after is not a listing key.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks listings:read, or its organization is not a member brokerage.

Status: 429
When: Over this key's requests per minute.

GET/api/v1/conflicts

Same address as another brokerage

Member brokerages only. Each of the caller's listings that was active at the same canonical address as another brokerage's active listing, open ones first. Addresses are compared after normalizing (St and Street, Apt and #, case, spacing). Of the other listing you see only its key, brokerage and status. The platform operator decides each one: a co-listing, a wrong address (naming which listing) or resolved; both owners get a history line and listing.conflict.

Auth: a Bearer key with listings:read.

Parameters

listingstring in query: ^OL-[A-Z0-9]{6}$; Only this listing's.
statusstring in query: open · all; open for undecided ones only; all (the default) for every one.

Request

curl "https://listonce.io/api/v1/conflicts" \
  -H "Authorization: Bearer $LISTONCE_KEY"

Response 200

{
  "value": [
    {
      "id": "4f1c2a9e-5b7d-4e3a-9c21-6d8e0f4b2a17",
      "status": "open",
      "listingKey": "OL-RCGZQ4",
      "other": {
        "listingKey": "OL-7MWX2D",
        "brokerage": "Bluebird Realty Co",
        "status": "Active"
      },
      "wrongListing": null,
      "createdAt": "2026-10-26T16:40:05.902Z",
      "decidedAt": null
    }
  ]
}

Status	When
200	Open first, then newest. At most 200.
400	An unknown parameter, a listing that is not a key, or a status other than open or all.
401	No key, a malformed key, or a revoked one.
403	The key lacks listings:read, or its organization is not a member brokerage.
429	Over this key's requests per minute.

Status: 200
When: Open first, then newest. At most 200.

Status: 400
When: An unknown parameter, a listing that is not a key, or a status other than open or all.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks listings:read, or its organization is not a member brokerage.

Status: 429
When: Over this key's requests per minute.

POST/api/v1/webhooks

Subscribe to listing changes

The URL must be https on the standard port, carry no credentials, and resolve only to public addresses (checked again at every send). At most 10 per organization. The signing secret is in this response only.

Auth: a Bearer key with webhooks:manage.

Parameters

Idempotency-Keystring in header: ^[\x21-\x7E]{1,200}$; Optional. Repeats with the same key and body replay the first response for 24 hours; the same key with a different body is refused.

Body

urlstringRequired: up to 500 chars; https URL on the standard port.
eventsarray of string: listing.created · listing.updated · listing.conflict; Defaults to listing.created and listing.updated. listing.conflict is sent only when asked for, and only member brokerages may ask (400 otherwise). Duplicates are dropped.

Request

curl -X POST "https://listonce.io/api/v1/webhooks" \
  -H "Authorization: Bearer $LISTONCE_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://example.com/hooks/listings",
    "events": [
      "listing.updated"
    ]
  }'

Response 201

{
  "id": "a7a332fd-bef7-4c6a-a362-9e9a3467e2d8",
  "url": "https://example.com/hooks/listings",
  "events": [
    "listing.updated"
  ],
  "active": true,
  "createdAt": "2026-10-26T15:10:03.520883+00:00",
  "secret": "whsec_4214177e6e99d1059b387b23bd89a068204cbd7b35b21692"
}

Status	When
201	Created. Store the secret now; it is not shown again.
400	Unknown field, bad events, or a URL that is not https, not public or does not resolve.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
409	The organization already has 10 webhooks, or a request with this Idempotency-Key is still running.
413	Body over 16,384 bytes.
422	This Idempotency-Key was used for a different body.
429	Over this key's requests per minute.

Status: 201
When: Created. Store the secret now; it is not shown again.

Status: 400
When: Unknown field, bad events, or a URL that is not https, not public or does not resolve.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 409
When: The organization already has 10 webhooks, or a request with this Idempotency-Key is still running.

Status: 413
When: Body over 16,384 bytes.

Status: 422
When: This Idempotency-Key was used for a different body.

Status: 429
When: Over this key's requests per minute.

GET/api/v1/webhooks

Your subscriptions

Every webhook of the key's organization, oldest first, with its most recent delivery.

Auth: a Bearer key with webhooks:manage.

Request

curl "https://listonce.io/api/v1/webhooks" \
  -H "Authorization: Bearer $LISTONCE_KEY"

Response 200

{
  "value": [
    {
      "id": "a7a332fd-bef7-4c6a-a362-9e9a3467e2d8",
      "url": "https://example.com/hooks/listings",
      "events": [
        "listing.updated"
      ],
      "active": true,
      "createdAt": "2026-10-26T15:10:03.520883+00:00",
      "lastDelivery": {
        "status": "sent",
        "code": 200,
        "attempts": 1,
        "at": "2026-10-26T16:40:06.114771+00:00"
      }
    }
  ]
}

Status	When
200	Webhooks.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
429	Over this key's requests per minute.

Status: 200
When: Webhooks.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 429
When: Over this key's requests per minute.

DELETE/api/v1/webhooks/{id}

Unsubscribe

Deletes the webhook and its delivery records.

Auth: a Bearer key with webhooks:manage.

Parameters

idstring in pathRequired: The webhook id. A malformed id answers 404.

Request

curl -X DELETE "https://listonce.io/api/v1/webhooks/a7a332fd-bef7-4c6a-a362-9e9a3467e2d8" \
  -H "Authorization: Bearer $LISTONCE_KEY"

Response 204

Deleted.

Status	When
204	Deleted.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such webhook for this key's organization.
429	Over this key's requests per minute.

Status: 204
When: Deleted.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such webhook for this key's organization.

Status: 429
When: Over this key's requests per minute.

POST/api/v1/keys/rotate

Rotate this key

Replaces the key that signs the request. The new key (same label, scopes and rate limit) is returned once and works at once; the old key keeps working for 24 hours, then stops. Rotating a key that is already being replaced answers 409, so store the new key before anything else. No body. The published demo key cannot be rotated.

Auth: a Bearer key with listings:write or listings:read or feed:read or webhooks:manage.

Request

curl -X POST "https://listonce.io/api/v1/keys/rotate" \
  -H "Authorization: Bearer $LISTONCE_KEY"

Response 201

{
  "key": "ol_live_3f9c0d2b7a8e4c1f9d6b5a4e3c2b1a0f9e8d7c6b",
  "id": "9b1c7e3a-4f2d-4c8b-a6e5-1d2c3b4a5f60",
  "prefix": "ol_live_3f9c0d",
  "previousKeyExpiresAt": "2026-10-28T15:10:03.520Z"
}

Status	When
201	The new key. It is not shown again.
401	No key, a malformed key, or a revoked one.
403	The published demo key, which is shared and cannot be rotated.
409	This key was already rotated; its replacement is the key to use.
429	Over this key's requests per minute.

Status: 201
When: The new key. It is not shown again.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The published demo key, which is shared and cannot be rotated.

Status: 409
When: This key was already rotated; its replacement is the key to use.

Status: 429
When: Over this key's requests per minute.

GET/api/reso

Service document

The OData service document: the entity sets this feed publishes.

Auth: a Bearer key with feed:read.

Parameters

keystring in query: The API key, for a browser link. Prefer the Authorization header: query strings end up in logs.

Request

curl "https://listonce.io/api/reso" \
  -H "Authorization: Bearer ol_demo_7f3a9c2e5b1d4086"

Response 200

{
  "@odata.context": "https://listonce.io/api/reso/$metadata",
  "value": [
    {
      "name": "Property",
      "kind": "EntitySet",
      "url": "Property"
    },
    {
      "name": "Media",
      "kind": "EntitySet",
      "url": "Media"
    },
    {
      "name": "Lookup",
      "kind": "EntitySet",
      "url": "Lookup"
    }
  ]
}

Status	When
200	Entity sets.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
429	Over this key's requests per minute.

Status: 200
When: Entity sets.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 429
When: Over this key's requests per minute.

GET/api/reso/$metadata

Data model

The OData CSDL XML for Property (with its Media navigation property), Media and Lookup, with RESO lookup annotations. Always XML; $format=json answers 415.

Auth: a Bearer key with feed:read.

Parameters

keystring in query: The API key, for a browser link. Prefer the Authorization header: query strings end up in logs.

Request

curl "https://listonce.io/api/reso/$metadata" \
  -H "Authorization: Bearer ol_demo_7f3a9c2e5b1d4086"

Response 200

application/xml.

Status	When
200	application/xml.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
429	Over this key's requests per minute.

Status: 200
When: application/xml.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 429
When: Over this key's requests per minute.

GET/api/reso/Lookup

Lookup values

Every lookup value the feed can send, as the RESO Lookup resource. Takes the same query options as Property.

Auth: a Bearer key with feed:read.

Parameters

keystring in query: The API key, for a browser link. Prefer the Authorization header: query strings end up in logs.

Request

curl "https://listonce.io/api/reso/Lookup" \
  -H "Authorization: Bearer ol_demo_7f3a9c2e5b1d4086"

Response 200

{
  "@odata.context": "https://listonce.io/api/reso/$metadata#Lookup",
  "value": [
    {
      "LookupKey": "StandardStatus:Active",
      "LookupName": "StandardStatus",
      "LookupValue": "Active",
      "StandardLookupValue": "Active",
      "LegacyODataValue": "Active",
      "ModificationTimestamp": "2026-10-26T00:00:00.000Z"
    }
  ]
}

Status	When
200	A page of lookup rows.
400	A query option the server cannot read.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
429	Over this key's requests per minute.

Status: 200
When: A page of lookup rows.

Status: 400
When: A query option the server cannot read.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 429
When: Over this key's requests per minute.

POST/api/reso/Property

Enter a listing in RESO fields

RESO Web API Add/Edit, for systems that already speak RESO. The same listing, rules and owner as POST /api/v1/listings, in Data Dictionary names plus two extensions: LO_SellerVisibilityChoice and LO_SellerName (write only; never in the feed). We assign ListingKey; read only fields (ListingKey, OriginatingSystemName, ListOfficeName, ModificationTimestamp, LO_SellerChoiceRecordedAt) and @odata. annotations are ignored, and any other name is refused. Baths: BathroomsFull with BathroomsHalf, or BathroomsTotalInteger alone. StandardStatus may be sent if it matches the seller's choice (Coming Soon for coming_soon, otherwise Active); OnMarketDate is the go live date for coming_soon. Errors carry target (Create) and details naming each field.

Auth: a Bearer key with listings:write.

Parameters

Idempotency-Keystring in header: ^[\x21-\x7E]{1,200}$; Optional. Repeats with the same key and body replay the first response for 24 hours; the same key with a different body is refused.
Preferstring in header: return=representation · return=minimal; Optional. return=representation answers with the record, return=minimal with no body; echoed in Preference-Applied. Without it a POST answers 201 with the record and a PATCH 204.

Body

UnparsedAddressstringRequired: Street, city, state ZIP. The text before the first comma is stored as the street (1 to 120 characters, no < or >); city, state and ZIP come from their own fields.
CitystringRequired: Austin · Charlotte · Phoenix · Tampa; Pilot market.
StateOrProvincestringRequired: TX · NC · AZ · FL; Two letter state; must match the city.
PostalCodestringRequired: ^\d{5}$; 5 digit ZIP.
ListPriceintegerRequired: 1 to 1,000,000,000; List price in whole dollars.
BedroomsTotalintegerRequired: 0 to 50; Bedrooms.
BathroomsFullinteger: 0 to 50; Full bathrooms. Send with BathroomsHalf.
BathroomsHalfinteger: 0 to 50; Half bathrooms, each counted as 0.5. Send with BathroomsFull (0 when there is none).
BathroomsTotalIntegerinteger: 0 to 50; Used only when BathroomsFull and BathroomsHalf are absent.
LivingAreaintegerRequired: 0 to 100,000; Living area in square feet.
LivingAreaUnitsstring: Square Feet; Only Square Feet.
LotSizeAcresnumber: 0 to 100,000, steps of 0.01; Lot size in acres.
YearBuiltinteger: 1700 to 2030; Year built.
PropertyTypestring: Residential; Only Residential.
PropertySubTypestringRequired: Single Family Residence · Townhouse · Condominium · Multi Family; RESO PropertySubType.
PublicRemarksstringRequired: 1 to 2000 chars; Public remarks. Not blank, no < or >.
ListAgentFullNamestringRequired: 1 to 80 chars; Listing agent's name. Cannot change after entry. Not blank, no < or >.
ListingContractDatestringRequired: YYYY-MM-DD; The day the listing agreement was signed. Within the last year, not after tomorrow (UTC). Cannot change after entry.
StandardStatusstring: Active · Coming Soon; Optional on create; must match the seller's choice.
OnMarketDatestring: YYYY-MM-DD; Go live date, required for coming_soon. Not in the past. Ignored for other choices.
LO_SellerVisibilityChoicestringRequired: public · coming_soon · members_only; Extension: the seller's choice: public, coming_soon or members_only.
LO_SellerNamestringRequired: 1 to 120 chars; Extension: the seller's name. Write only: seen by the owner, never in the feed. Cannot change after entry. Not blank, no < or >.
ListingKeystring or null: We assign the key; on a PATCH, any other key than the record's own is refused. Read only: ignored.
OriginatingSystemNamestring or null: Always this platform. Read only: ignored.
ListOfficeNamestring or null: The caller's brokerage. Read only: ignored.
ModificationTimestampstring or null: Set on every change. Read only: ignored.
LO_SellerChoiceRecordedAtstring or null: Set when the choice changes. Read only: ignored.

Request

curl -X POST "https://listonce.io/api/reso/Property" \
  -H "Authorization: Bearer $LISTONCE_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "UnparsedAddress": "88 Cedar Bluff Dr, Austin, TX 78704",
    "City": "Austin",
    "StateOrProvince": "TX",
    "PostalCode": "78704",
    "ListPrice": 625000,
    "BedroomsTotal": 3,
    "BathroomsFull": 2,
    "BathroomsHalf": 1,
    "LivingArea": 1960,
    "LotSizeAcres": 0.18,
    "YearBuilt": 2004,
    "PropertyType": "Residential",
    "PropertySubType": "Single Family Residence",
    "PublicRemarks": "Quiet street, open kitchen and a covered patio facing the greenbelt.",
    "ListAgentFullName": "Rowan Ellis",
    "ListingContractDate": "2026-10-26",
    "LO_SellerVisibilityChoice": "members_only",
    "LO_SellerName": "A. and T. Monroe"
  }'

Response 201

{
  "@odata.context": "https://listonce.io/api/reso/$metadata#Property/$entity",
  "ListingKey": "OL-RCGZQ4",
  "OriginatingSystemName": "ListOnce",
  "StandardStatus": "Active",
  "ListPrice": 625000,
  "ClosePrice": null,
  "UnparsedAddress": "88 Cedar Bluff Dr, Austin, TX 78704",
  "City": "Austin",
  "StateOrProvince": "TX",
  "PostalCode": "78704",
  "PropertyType": "Residential",
  "PropertySubType": "Single Family Residence",
  "BedroomsTotal": 3,
  "BathroomsTotalInteger": 3,
  "BathroomsFull": 2,
  "BathroomsHalf": 1,
  "LivingArea": 1960,
  "LivingAreaUnits": "Square Feet",
  "LotSizeAcres": 0.18,
  "YearBuilt": 2004,
  "PublicRemarks": "Quiet street, open kitchen and a covered patio facing the greenbelt.",
  "ListAgentFullName": "Rowan Ellis",
  "ListOfficeName": "Harbor & Pine Realty",
  "ListingContractDate": "2026-10-26",
  "OnMarketDate": "2026-10-26",
  "ModificationTimestamp": "2026-10-26T15:04:12.318Z",
  "LO_SellerVisibilityChoice": "members_only",
  "LO_SellerChoiceRecordedAt": "2026-10-26T15:04:12.318Z"
}

Status	When
201	Created. The record as the owner sees it.
204	Created, with `Prefer: return=minimal`.
400	A field failed validation, is missing or is unknown. details names each field.
401	No key, a malformed key, or a revoked one.
403	The key lacks listings:write, or its organization is not a member brokerage.
409	The brokerage already has an active listing (Coming Soon, Active or Pending) at this address: existingKey names it. Update that listing, or withdraw it before listing again. Or a request with this Idempotency-Key is still running.
413	Body over 16,384 bytes.
422	This Idempotency-Key was used for a different body.
429	Over this key's requests per minute.

Status: 201
When: Created. The record as the owner sees it.

Status: 204
When: Created, with Prefer: return=minimal.

Status: 400
When: A field failed validation, is missing or is unknown. details names each field.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks listings:write, or its organization is not a member brokerage.

Status: 409
When: The brokerage already has an active listing (Coming Soon, Active or Pending) at this address: existingKey names it. Update that listing, or withdraw it before listing again. Or a request with this Idempotency-Key is still running.

Status: 413
When: Body over 16,384 bytes.

Status: 422
When: This Idempotency-Key was used for a different body.

Status: 429
When: Over this key's requests per minute.

GET/api/reso/Property

Search the feed

RESO Web API Core style. Newest change first unless $orderby says otherwise, then by key. Members only and coming soon listings are never included. Pages hold at most 50 records; a nextLink follows when the server cut a page short. Property('OL-4K7Q2M') fetches one record too.

Auth: a Bearer key with feed:read.

Parameters

$topinteger in query: 0 to undefined; How many records you want. The server sends at most 50 per page.
$skipinteger in query: 0 to 100,000; Records to skip, up to 100,000.
$filterstring in query: up to 2000 chars; OData: eq ne gt ge lt le, and or not, parentheses, null with eq and ne. Strings in single quotes, dates as YYYY-MM-DD, timestamps in ISO 8601. Fields: ListingKey, StandardStatus, ListPrice, ClosePrice, City, StateOrProvince, PostalCode, PropertySubType, BedroomsTotal, LivingArea, LotSizeAcres, YearBuilt, ListAgentFullName, ListOfficeName, ListingContractDate, ModificationTimestamp.
$selectstring in query: Comma separated fields to return.
$orderbystring in query: Up to 5 filterable fields, each optionally asc or desc.
$countstring in query: true · false; true adds @odata.count.
$expandstring in query: Media; Media adds each record's photos, in order, as a Media array. Nothing else expands.
keystring in query: The API key, for a browser link. Prefer the Authorization header: query strings end up in logs.

Request

curl "https://listonce.io/api/reso/Property" \
  -H "Authorization: Bearer ol_demo_7f3a9c2e5b1d4086"

Response 200

{
  "@odata.context": "https://listonce.io/api/reso/$metadata#Property",
  "@odata.count": 1,
  "value": [
    {
      "ListingKey": "OL-4K7Q2M",
      "OriginatingSystemName": "ListOnce",
      "StandardStatus": "Active",
      "ListPrice": 589000,
      "ClosePrice": null,
      "UnparsedAddress": "1418 Larkspur Way, Austin, TX 78745",
      "City": "Austin",
      "StateOrProvince": "TX",
      "PostalCode": "78745",
      "PropertyType": "Residential",
      "PropertySubType": "Single Family Residence",
      "BedroomsTotal": 3,
      "BathroomsTotalInteger": 2,
      "BathroomsFull": 2,
      "BathroomsHalf": 0,
      "LivingArea": 1840,
      "LivingAreaUnits": "Square Feet",
      "LotSizeAcres": 0.21,
      "YearBuilt": 1998,
      "PublicRemarks": "Shaded corner lot, updated kitchen, two living areas and a deep backyard with mature oaks.",
      "ListAgentFullName": "Dana Whitfield",
      "ListOfficeName": "Harbor & Pine Realty",
      "ListingContractDate": "2026-10-24",
      "OnMarketDate": "2026-10-24",
      "ModificationTimestamp": "2026-10-24T21:03:00.000Z",
      "LO_SellerVisibilityChoice": "public",
      "LO_SellerChoiceRecordedAt": "2026-10-24T10:20:00.000Z"
    }
  ]
}

Status	When
200	A page of RESO records.
400	A query option the server cannot read: an unknown field, operator or option.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
429	Over this key's requests per minute.

Status: 200
When: A page of RESO records.

Status: 400
When: A query option the server cannot read: an unknown field, operator or option.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 429
When: Over this key's requests per minute.

PATCH/api/reso/Property('{key}')

Change a listing in RESO fields

RESO Web API Add/Edit. Owner only, with the same rules as PATCH /api/v1/listings/{key}: send just the fields that change; null clears LotSizeAcres or YearBuilt. OnMarketDate sets the go live date while the listing is Coming Soon and is ignored otherwise. ListAgentFullName, ListingContractDate and LO_SellerName cannot change. A record read from this API can be sent back whole: read only fields are ignored. Also answers at /api/reso/Property/{key}. Honors Idempotency-Key.

Auth: a Bearer key with listings:write.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.
Idempotency-Keystring in header: ^[\x21-\x7E]{1,200}$; Optional. Repeats with the same key and body replay the first response for 24 hours; the same key with a different body is refused.
Preferstring in header: return=representation · return=minimal; Optional. return=representation answers with the record, return=minimal with no body; echoed in Preference-Applied. Without it a POST answers 201 with the record and a PATCH 204.

Body

UnparsedAddressstring: Street, city, state ZIP. The text before the first comma is stored as the street (1 to 120 characters, no < or >); city, state and ZIP come from their own fields.
Citystring: Austin · Charlotte · Phoenix · Tampa; Pilot market.
StateOrProvincestring: TX · NC · AZ · FL; Two letter state; must match the city.
PostalCodestring: ^\d{5}$; 5 digit ZIP.
ListPriceinteger: 1 to 1,000,000,000; List price in whole dollars.
BedroomsTotalinteger: 0 to 50; Bedrooms.
BathroomsFullinteger: 0 to 50; Full bathrooms. Send with BathroomsHalf.
BathroomsHalfinteger: 0 to 50; Half bathrooms, each counted as 0.5. Send with BathroomsFull (0 when there is none).
BathroomsTotalIntegerinteger: 0 to 50; Used only when BathroomsFull and BathroomsHalf are absent.
LivingAreainteger: 0 to 100,000; Living area in square feet.
LivingAreaUnitsstring: Square Feet; Only Square Feet.
LotSizeAcresnumber or null: 0 to 100,000, steps of 0.01; Lot size in acres. null clears it.
YearBuiltinteger or null: 1700 to 2030; Year built. null clears it.
PropertyTypestring: Residential; Only Residential.
PropertySubTypestring: Single Family Residence · Townhouse · Condominium · Multi Family; RESO PropertySubType.
PublicRemarksstring: 1 to 2000 chars; Public remarks. Not blank, no < or >.
ListAgentFullNamestring: 1 to 80 chars; Listing agent's name. Cannot change after entry. Not blank, no < or >.
ListingContractDatestring: YYYY-MM-DD; The day the listing agreement was signed. Within the last year, not after tomorrow (UTC). Cannot change after entry.
StandardStatusstring: Coming Soon · Active · Pending · Closed · Withdrawn; New status.
OnMarketDatestring or null: YYYY-MM-DD; Go live date while Coming Soon; ignored otherwise.
LO_SellerVisibilityChoicestring: public · coming_soon · members_only; Extension: the seller's choice: public, coming_soon or members_only.
LO_SellerNamestring: 1 to 120 chars; Extension: the seller's name. Write only: seen by the owner, never in the feed. Cannot change after entry. Not blank, no < or >.
ListingKeystring or null: We assign the key; on a PATCH, any other key than the record's own is refused. Read only: ignored.
OriginatingSystemNamestring or null: Always this platform. Read only: ignored.
ListOfficeNamestring or null: The caller's brokerage. Read only: ignored.
ModificationTimestampstring or null: Set on every change. Read only: ignored.
LO_SellerChoiceRecordedAtstring or null: Set when the choice changes. Read only: ignored.
ClosePriceinteger or null: 1 to 1,000,000,000; Sold price; only when the status is Closed. null is ignored.

Request

curl -X PATCH "https://listonce.io/api/reso/Property('OL-4K7Q2M')" \
  -H "Authorization: Bearer $LISTONCE_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "ListPrice": 615000,
    "StandardStatus": "Pending"
  }'

Response 200

{
  "@odata.context": "https://listonce.io/api/reso/$metadata#Property/$entity",
  "ListingKey": "OL-RCGZQ4",
  "OriginatingSystemName": "ListOnce",
  "StandardStatus": "Pending",
  "ListPrice": 615000,
  "ClosePrice": null,
  "UnparsedAddress": "88 Cedar Bluff Dr, Austin, TX 78704",
  "City": "Austin",
  "StateOrProvince": "TX",
  "PostalCode": "78704",
  "PropertyType": "Residential",
  "PropertySubType": "Single Family Residence",
  "BedroomsTotal": 3,
  "BathroomsTotalInteger": 3,
  "BathroomsFull": 2,
  "BathroomsHalf": 1,
  "LivingArea": 1960,
  "LivingAreaUnits": "Square Feet",
  "LotSizeAcres": 0.18,
  "YearBuilt": 2004,
  "PublicRemarks": "Quiet street, open kitchen and a covered patio facing the greenbelt.",
  "ListAgentFullName": "Rowan Ellis",
  "ListOfficeName": "Harbor & Pine Realty",
  "ListingContractDate": "2026-10-26",
  "OnMarketDate": "2026-10-26",
  "ModificationTimestamp": "2026-10-26T16:40:05.902Z",
  "LO_SellerVisibilityChoice": "members_only",
  "LO_SellerChoiceRecordedAt": "2026-10-26T15:04:12.318Z"
}

Status	When
200	Changed, with `Prefer: return=representation`: the record as the owner sees it.
204	Changed. No body unless `Prefer: return=representation`.
400	A field failed validation or is unknown, a cross field rule failed, or nothing would change. details names the field.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	No such listing owned by this key's brokerage.
409	The brokerage already has an active listing (Coming Soon, Active or Pending) at this address: existingKey names it. Update that listing, or withdraw it before listing again. Or the listing changed while this request ran, or a request with this Idempotency-Key is still running.
413	Body over 16,384 bytes.
422	This Idempotency-Key was used for a different body.
429	Over this key's requests per minute.

Status: 200
When: Changed, with Prefer: return=representation: the record as the owner sees it.

Status: 204
When: Changed. No body unless Prefer: return=representation.

Status: 400
When: A field failed validation or is unknown, a cross field rule failed, or nothing would change. details names the field.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: No such listing owned by this key's brokerage.

Status: 409
When: The brokerage already has an active listing (Coming Soon, Active or Pending) at this address: existingKey names it. Update that listing, or withdraw it before listing again. Or the listing changed while this request ran, or a request with this Idempotency-Key is still running.

Status: 413
When: Body over 16,384 bytes.

Status: 422
When: This Idempotency-Key was used for a different body.

Status: 429
When: Over this key's requests per minute.

GET/api/reso/Property/{key}

One listing from the feed

The RESO record, while the listing may be publicly marketed.

Auth: a Bearer key with feed:read.

Parameters

keystring in pathRequired: ^OL-[A-Z0-9]{6}$; The listing key. A key of the wrong shape answers 404, like a missing one.
$expandstring in query: Media; Media adds each record's photos, in order, as a Media array. Nothing else expands.
keystring in query: The API key, for a browser link. Prefer the Authorization header: query strings end up in logs.

Request

curl "https://listonce.io/api/reso/Property/OL-4K7Q2M" \
  -H "Authorization: Bearer ol_demo_7f3a9c2e5b1d4086"

Response 200

{
  "@odata.context": "https://listonce.io/api/reso/$metadata#Property/$entity",
  "ListingKey": "OL-4K7Q2M",
  "OriginatingSystemName": "ListOnce",
  "StandardStatus": "Active",
  "ListPrice": 589000,
  "ClosePrice": null,
  "UnparsedAddress": "1418 Larkspur Way, Austin, TX 78745",
  "City": "Austin",
  "StateOrProvince": "TX",
  "PostalCode": "78745",
  "PropertyType": "Residential",
  "PropertySubType": "Single Family Residence",
  "BedroomsTotal": 3,
  "BathroomsTotalInteger": 2,
  "BathroomsFull": 2,
  "BathroomsHalf": 0,
  "LivingArea": 1840,
  "LivingAreaUnits": "Square Feet",
  "LotSizeAcres": 0.21,
  "YearBuilt": 1998,
  "PublicRemarks": "Shaded corner lot, updated kitchen, two living areas and a deep backyard with mature oaks.",
  "ListAgentFullName": "Dana Whitfield",
  "ListOfficeName": "Harbor & Pine Realty",
  "ListingContractDate": "2026-10-24",
  "OnMarketDate": "2026-10-24",
  "ModificationTimestamp": "2026-10-24T21:03:00.000Z",
  "LO_SellerVisibilityChoice": "public",
  "LO_SellerChoiceRecordedAt": "2026-10-24T10:20:00.000Z"
}

Status	When
200	The RESO record.
400	$expand names something other than Media.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
404	Not in the feed: missing, members only or coming soon.
429	Over this key's requests per minute.

Status: 200
When: The RESO record.

Status: 400
When: $expand names something other than Media.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 404
When: Not in the feed: missing, members only or coming soon.

Status: 429
When: Over this key's requests per minute.

GET/api/reso/Media

Photos in the feed

The RESO Media resource: photos of the listings in the feed only, newest change first unless $orderby says otherwise, then by MediaKey. Takes the same query options as Property; pages hold at most 100. Media('OLP-7RQ2KD9XWM') fetches one. A feed link stops working as soon as its listing leaves the feed. MediaURL is a signed link on this host that lasts about 12 hours: store the photo, not the link.

Auth: a Bearer key with feed:read.

Parameters

$filterstring in query: up to 2000 chars; As on Property. PreferredPhotoYN takes true or false with eq and ne. Fields: MediaKey, ResourceRecordKey, MediaCategory, Order, ImageWidth, ImageHeight, PreferredPhotoYN, ModificationTimestamp.
keystring in query: The API key, for a browser link. Prefer the Authorization header: query strings end up in logs.

Request

curl "https://listonce.io/api/reso/Media" \
  -H "Authorization: Bearer ol_demo_7f3a9c2e5b1d4086"

Response 200

{
  "@odata.context": "https://listonce.io/api/reso/$metadata#Media",
  "value": [
    {
      "MediaKey": "OLP-7RQ2KD9XWM",
      "ResourceRecordKey": "OL-4K7Q2M",
      "ResourceName": "Property",
      "MediaCategory": "Photo",
      "MediaURL": "https://listonce.io/m/OLP-7RQ2KD9XWM.jpg?a=p&e=1793095200&s=Jp2c1v9yQkXo3H7bTn0aLw5rUe8sDf4gZi6mCxVhKqY",
      "Order": 0,
      "ImageWidth": 2560,
      "ImageHeight": 1707,
      "PreferredPhotoYN": true,
      "ModificationTimestamp": "2026-10-26T15:20:41.000Z"
    },
    {
      "MediaKey": "OLP-C4HNV8TZ3P",
      "ResourceRecordKey": "OL-4K7Q2M",
      "ResourceName": "Property",
      "MediaCategory": "Photo",
      "MediaURL": "https://listonce.io/m/OLP-C4HNV8TZ3P.jpg?a=p&e=1793095200&s=Jp2c1v9yQkXo3H7bTn0aLw5rUe8sDf4gZi6mCxVhKqY",
      "Order": 1,
      "ImageWidth": 2560,
      "ImageHeight": 1707,
      "PreferredPhotoYN": false,
      "ModificationTimestamp": "2026-10-26T15:20:41.000Z"
    }
  ]
}

Status	When
200	A page of Media records.
400	A query option the server cannot read.
401	No key, a malformed key, or a revoked one.
403	The key lacks the scope this route needs.
429	Over this key's requests per minute.

Status: 200
When: A page of Media records.

Status: 400
When: A query option the server cannot read.

Status: 401
When: No key, a malformed key, or a revoked one.

Status: 403
When: The key lacks the scope this route needs.

Status: 429
When: Over this key's requests per minute.

A photo in three calls

The file goes straight to storage, so it can be up to 8 MB. Nothing is a photo until the last call has checked it, removed its location data and stored it.

curl

UPLOAD=$(curl -s -X POST "https://listonce.io/api/v1/listings/OL-4K7Q2M/media/uploads" \
  -H "Authorization: Bearer $LISTONCE_KEY")
curl -X PUT "$(echo "$UPLOAD" | jq -r .uploadUrl)" \
  -H "Content-Type: image/jpeg" --data-binary @front.jpg
curl -X POST "https://listonce.io/api/v1/listings/OL-4K7Q2M/media" \
  -H "Authorization: Bearer $LISTONCE_KEY" -H "Content-Type: application/json" \
  -d "{\"uploadId\": \"$(echo "$UPLOAD" | jq -r .uploadId)\"}"

Error body

{
  "error": {
    "code": "400",
    "message": "zip must be a 5 digit ZIP"
  }
}