> ## Documentation Index
> Fetch the complete documentation index at: https://docs.andteam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# precondition-required

> An If-Match header is required.

**Status 428.** An If-Match header is required.

The response is `application/problem+json`, and its `type` is
`https://docs.andteam.com/api/problems/precondition-required`:

```json theme={null}
{
  "type": "https://docs.andteam.com/api/problems/precondition-required",
  "title": "An If-Match header is required",
  "status": 428
}
```

## What it means

This request changes a record and needs `If-Match` with the record's `ETag`.

## What to do

Read the record, then send its `ETag` as `If-Match`. See [Retries and versions](https://docs.andteam.com/guides/idempotency.md).

See [Errors](https://docs.andteam.com/errors.md) for every type.


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