# Authentication for agents

Increase is a banking API. Agents can obtain a sandbox API key without a human signing up for an account.

## Anonymous sandbox registration

Create a sandbox Group (an organization on Increase) with a single unauthenticated request:

```
POST https://sandbox.increase.com/groups
```

The request takes no parameters. The response includes a `sandbox_api_key`:

```
{
  "created_at": "2026-01-31T23:59:59Z",
  "sandbox_api_key": "sk0LMB5dIbTBg0IqPgug5jZuByAsqu32"
}
```

Use the key as a bearer token against `https://sandbox.increase.com` for every endpoint in the [API reference](https://increase.com/documentation/api):

```
GET https://sandbox.increase.com/groups/current
Authorization: Bearer sk0LMB5dIbTBg0IqPgug5jZuByAsqu32
```

Your sandbox comes provisioned with a Program. Create an Entity, then an Account, and you can start moving simulated money. The full API surface is described in [llms.txt](https://increase.com/llms.txt) and the [documentation](https://increase.com/documentation.md).

## Notes for agents

- Sandbox keys only work against `sandbox.increase.com`. Groups created this way can never hold production credentials. To use Increase in production, a human must [sign up for an account](https://dashboard.increase.com).
- Instead of creating webhook Event Subscriptions, poll `GET /events` for updates.
- Store the returned `sandbox_api_key`. It is only returned when the Group is created.
- Registration is rate limited per IP address. Reuse one sandbox Group per project rather than creating a new one per session.