PactFlow uses conventional HTTP response codes to indicate the success or failure of an API request.

In general:

  • Codes in the 2xx range indicate success.
  • Codes in the 4xx range indicate an error that failed given the information provided (e.g., a required parameter was omitted, a charge failed, etc.).
  • Codes in the 5xx range indicate an error with PactFlow's servers (these are rare).

Extended Errors with Problem Details

When the Accept header includes application/problem+json media type, the "Problem Detail" error type as described in RFC9457 (formally RFC7808) communicate details about an error and is intended for use with HTTP status codes in the 4xx and 5xx series.


  -H"Accept: application/json, application/hal+json, application/problem+json" \
  -H"Authorization: Bearer <token>" \

This will result in an error like this:

  "title": "Validation errors",
  "type": "",
  "status": 400,
  "instance": "/",
  "errors": [
      "detail": "is missing",
      "pointer": "#/name"

NOTE: as is shown here, some resources contain the additional errors extension property containing an array of error messages.

Without the application/problem+json header, a legacy format is used in one of the following formats:

{ "errors": ["message"]}
{ "error": "message" }
{ "errors": { "<key>": ["message"] }}

We consider the legacy format deprecated and will remove it in the next major version, therefore it is strongly recommended to opt-in to the Problem JSON error format.

To learn more about the types of problem-details that are possible, check out the SmartBear Problem Details Registry