Requests & Responses

JSON everywhere

All requests and responses are JSON. Send Content-Type: application/json on any request that has a body.

curl -X POST https://rentsimple.ai/api/v1/properties \
  -H "Authorization: Bearer $RENTSIMPLE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "name": "Elm Street Residences", "address": { ... } }'

The data envelope

Successful reads and writes return the affected object(s) under a top-level data key. Timestamps are ISO-8601 (UTC).

{
  "data": {
    "id": 412,
    "name": "Elm Street Residences",
    "createdAt": "2026-06-05T14:22:08Z",
    "updatedAt": "2026-06-05T14:22:08Z"
  }
}

{
  "data": [
    { "id": 1287, "name": "B2 — Two Bedroom" }
  ]
}

Some write endpoints, such as deletes and the create-lead call, instead return a simple acknowledgement:

{ "message": "OK" }

External identifiers

Every resource accepts an optional externalId: your own identifier, echoed back on reads, so you can map RentSimple records to your system without a lookup table.

External IDs are unique per company for properties, and unique per property for floorplans and units. Reusing one within its scope returns 409 Duplicate externalId.

{
  "data": {
    "id": 412,
    "name": "Elm Street Residences",
    "externalId": "yardi-0042"
  }
}