> For the complete documentation index, see [llms.txt](https://developers.bead.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.bead.xyz/faqs-and-troubleshooting/webhooks-and-error-codes/how-do-i-resolve-a-400-validationerror.md).

# How do I resolve a 400 ValidationError?

A **400** response means your request JSON didn't meet Bead's validation requirements. The response body tells you exactly which field failed and why.

### Understanding the error response

The response is an RFC 9110 Problem Details object:

```json
{
  "type": "https://tools.ietf.org/html/rfc9110#section-15.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "errors": {
    "Customer.FirstName": [
      "The FirstName field is required."
    ]
  },
  "traceId": "00-0000000000000000000000000000000-0000000000000000-00"
}
```

* **`type`** — a URL identifying the RFC 9110 status section for this response.
* **`title`** — a short, human-readable summary; for validation failures this is always `"One or more validation errors occurred."`.
* **`status`** — the HTTP status code, duplicated in the body.
* **`errors`** — an object keyed by the **PascalCase, dot-delimited path** of each failing field (for example, `Customer.FirstName`), where each value is an **array of message strings** for that field.
* **`traceId`** — a [W3C trace-context](https://www.w3.org/TR/trace-context/#traceparent-header) identifier. Include this when contacting Bead support.

There is no `code` or flat `field`/`message` pair at the top level — parse `errors` as a map of field path to message array, not a single object or array of objects.

See [Submit Application](/onboarding/submit-application.md) for the full confirmed reference, including the field-path naming convention.

### Common issues and solutions

**Customer field requirements**\
An error under a `Customer.*` path (for example, `Customer.FirstName is required`) usually means a customer subfield was included without the rest of the required customer fields. Provide the complete set of required fields, or omit the `customer` object entirely.

**Amount validation**\
A `requestedAmount must be > 0` message means the field was zero or negative. Submit a positive decimal value.

**Merchant ID issues**\
A `merchantId not found` message means the ID doesn't match your authenticated terminal. Verify you're using the correct merchant ID for the environment you're calling.

**URL format errors**\
A `webhookUrls must be an array of https URLs` message means the value wasn't sent as an array, or one of the URLs isn't HTTPS. A `redirectUrl must be https` message means that field is missing the HTTPS scheme.

### Troubleshooting steps

1. Validate your request JSON's syntax before sending.
2. Confirm field types match the schema (unquoted numbers, quoted strings, arrays wrapped in brackets).
3. Match enum values exactly, including capitalization.
4. Cross-check field names and requirements against the current OpenAPI specification.
5. Check the failing field paths in `errors` against [Field Validation Rules](/onboarding/field-validation-rules.md) — most common failures are documented there with their fix.
6. Retain sanitized request and response logs (including `traceId`) for comparison.

### Quick testing

Use the sandbox environment at `https://api.test.devs.beadpay.io` to test corrections before deploying to production. Postman, cURL, or a schema validator can help you narrow down a failure quickly.

### Contacting support

If the error remains unclear, or you believe the value you sent is valid, contact <developers@bead.xyz> with the full response body (including `traceId`), the request body, the terminal ID, and the call timestamp — with all credentials masked.

#### Related pages

* [Submit Application](/onboarding/submit-application.md)
* [Field Validation Rules](/onboarding/field-validation-rules.md)
* [Error Codes](/reference-guide/core-concepts/error-codes.md)


---

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