Vantage API: Errors

The Lokalise Vantage API returns errors in a consistent JSON format across all endpoints and HTTP status codes.

Each error contains:

• message — a human-readable description of the error.
• code — an error-specific code that can be used programmatically.
• details — optional additional information that can help identify the cause of the error.

Single errors

When a request produces a single error, the error object is returned directly at the response root:

{
  "message": "The requested resource was not found.",
  "code": "resource_not_found"
}

Some errors may also include the optional details object:

{
  "message": "The request could not be processed.",
  "code": "invalid_request",
  "details": {
    "field": "projectId"
  }
}

Multiple errors

When several errors are returned, for example during request validation, they are grouped under the root-level errors property:

{
  "errors": [
    {
      "message": "Invalid value.",
      "code": "validation_error",
      "details": {
        "field": "name"
      }
    },
    {
      "message": "Invalid value.",
      "code": "validation_error",
      "details": {
        "field": "language"
      }
    }
  ]
}

Each object in the errors array uses the same error structure as a single error.

API clients should therefore handle both possible response shapes:

Single error:
{
  "message": "...",
  "code": "...",
  "details": { ... }
}

Multiple errors:
{
  "errors": [
    {
      "message": "...",
      "code": "...",
      "details": { ... }
    }
  ]
}

Use the HTTP status code to determine the general result of the request and the error code, message, and optional details fields to identify the specific cause.