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

# Authentication

> Customer API keys (dm_live_…) as a Bearer token on match endpoints.

## Getting a key

API keys are issued by The Data City. A key:

* Starts with `dm_live_`
* Is shown in full **once** at creation — store it immediately
* Can be revoked; revoked keys return `401`

Contact [support@thedatacity.com](mailto:support@thedatacity.com) if you need a key or a rotation.

## Using the key

Add an `Authorization` header to every match request:

```http theme={null}
Authorization: Bearer dm_live_…
```

Example:

```bash theme={null}
curl -sS -X POST "https://datamatcher-api.thedatacity.com/api/v1/match" \
  -H "Authorization: Bearer dm_live_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"input_name":"John Lewis plc"}'
```

<Note>
  Treat your API key like a password. Store it in an environment variable or secrets manager. Never check it into source control or include it in client-side code.
</Note>

## What the key is not

Dashboard login uses a separate OAuth2 password flow (`POST /api/v1/login/access-token`) and returns a JWT. That JWT is for the admin UI and administrative APIs. **Match calls must use a `dm_live_…` API key.**

If you send a JWT to `/match`, expect `401`.

## Failure modes

| Status | Meaning                                                    | What to do                                                         |
| ------ | ---------------------------------------------------------- | ------------------------------------------------------------------ |
| `401`  | Missing header, malformed key, unknown key, or revoked key | Check the key value; request a new one if revoked                  |
| `429`  | Too many match requests                                    | Back off — see [Rate limits](/company-matching/guides/rate-limits) |

See [Errors](/company-matching/guides/errors) for the full status-code matrix.