# invalid_request

The request body or parameters failed validation. What causes the BioFlow API's invalid_request error (HTTP 400) and how to fix it.

HTTP 400 · `application/problem+json` · The request body or parameters failed validation.

## What causes it

- A required field is missing, the wrong type, or fails validation (the `errors` array lists each offending field as a JSON Pointer).
- The request body is not valid JSON, or a query/path parameter is malformed.

## How to fix it

- Read the `errors` array — each entry carries a pointer (e.g. `/title`), a field-level code, and a message.
- Validate against the OpenAPI 3.1 spec ([/docs/api/openapi.json](/docs/api/openapi.json)); it describes every field's type and constraints.

## Example response body

```json
{
  "type": "https://getbioflow.com/docs/api/errors/invalid-request",
  "title": "The request body or parameters failed validation",
  "status": 400,
  "detail": "The request body failed validation.",
  "instance": "urn:request:req_01abc",
  "code": "invalid_request",
  "request_id": "req_01abc"
}
```

Branch on the stable `code` field — `title` and `detail` are for humans and may
change. `type` (`https://getbioflow.com/docs/api/errors/invalid-request`) always resolves to this page. Quote
`request_id` when contacting support. Full code registry on the
[API docs hub](/docs/api#errors); the complete surface is in the
[interactive reference](/docs/api-reference).