---
title: 1001: Field required. | API Docs
description: A required field is absent, null or empty.
---

**HTTP status:** `422`. May also be reported as a field-level finding in `error.details[]`.

The field named by param is required for this operation or part and was missing, null or empty. Supply a value and resend; nothing was recorded.

## Troubleshooting

- Inspect error.param (or details\[].param) for the exact JSON Pointer to the missing field.
- Compare the part against GET /v1/parts/{type}, which lists every required field.

## Related

- [Part schemas](/channel/whatsapp/api/resources/contract/methods/part_schema/index.md)
- [Sending a message](/channel/whatsapp/api/resources/chats/subresources/messages/methods/send/index.md)