Errors

Success shape

Every successful response looks like this:

{
  "status": "success",
  "message": "Human-readable summary of what happened.",
  "data": { }
}

data is endpoint-specific — see each operation’s reference page for its shape. data may be null for actions that don’t return a resource (a toggle, a delete).

Error shape

{
  "status": "error",
  "message": "Human-readable, safe to show a user.",
  "error_code": "ACCOUNT_NOT_FOUND",
  "request_id": "a1b2c3d4-...",
  "errors": { }
}

message is written to be shown directly to an end user if you want to.
error_code is the stable, machine-readable field — switch your code on this, not on message (wording can change; the code won’t). Every code used across this API is documented on the operation that returns it.
request_id — include this when contacting support about a specific failed call.
errors is only present on 422 validation failures — an object keyed by field name, each value an array of messages:

{
  "status": "error",
  "message": "Validation failed.",
  "error_code": "VALIDATION_FAILED",
  "errors": {
    "email": ["The email field is required."]
  }
}

HTTP status codes used

Status	Default `message` / `error_code`	Meaning
`200`	—	Success.
`401`	”Unauthenticated.” / `UNAUTHENTICATED`	Missing, invalid, or expired bearer token — see Authentication.
`403`	”Forbidden.” / `FORBIDDEN`	Authenticated, but not allowed to do this, or a feature is gated to Rex’s own test environment — though most `403`s in this API return a more specific `error_code` on the operation itself rather than this generic one.
`404`	”Resource not found.” / `NOT_FOUND`	The resource, or the specific thing you asked about, doesn’t exist. Most operations return a more specific code (e.g. `ACCOUNT_NOT_FOUND`).
`409`	”Request conflict.” / `CONFLICT`	Something about current state blocks this — almost always documented with a specific code on the operation (`DUPLICATE_REFERENCE`, `PROFILE_LOCKED`, `FBO_NOT_PROVISIONED`, …).
`422`	”Request could not be processed.” / `UNPROCESSABLE_ENTITY`, or `"Validation failed."` / `VALIDATION_FAILED` with `errors` populated	A body validation failure, or a business precondition your request can’t currently satisfy — check the operation’s documented `error_code`s.
`429`	”Too many requests. Please try again later.” / `TOO_MANY_REQUESTS`	Rate limited — see Rate Limits.
`500`	Always a generic, safe message — see below	Something went wrong on our end.

A note on `error_code` values

error_code is only guaranteed present when it’s genuinely one of ours — you’ll notice each operation’s reference lists a specific, finite set (e.g. ACCOUNT_NOT_FOUND, INSUFFICIENT_BALANCE, DUPLICATE_REFERENCE). Don’t assume every possible failure has a code beyond that documented set.

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Webhooks

Guides

Success shape

Error shape

HTTP status codes used

A note on `error_code` values

Success shape

Error shape

HTTP status codes used

A note on error_code values

A note on `error_code` values