How errors work

Every error has the content type application/problem+json and this shape (RFC 9457).

{
  "type": "https://docs.customer.onsim.uk/errors/invalid-request",
  "title": "The request is not valid",
  "status": 400,
  "errors": [
    { "field": "from", "detail": "is required" }
  ]
}

Field	Meaning
type	The kind of error. It is a link to a page of this section. Decide on this field, not on the title.
title	A short summary of the kind of error.
status	The HTTP status.
detail	What went wrong in this request. Not every error has it.
errors	Each parameter that is not valid. Only invalid-request has it, and not every invalid-request does.

Should you send the request again?

Problem	Send it again?
rate-limited, service-unavailable, timeout	Yes, after a wait.
quota-exceeded	Yes, on the next day (UTC).
internal-error	Once. If it fails again, tell us.
Every other problem	No. Change the request first.