![](/img/icons/guides.svg)

# Guides

Guides to address verification, integrating our products and managing your account.

[01**API Key**Where to find your key, and what each key controls](/docs/guides/api-key.md)[02**Testing**Separate test and production keys, and `ak_test` for quick checks](/docs/guides/testing.md)[03**AI Assist**llms.txt, the CLI and setup for coding agents and app builders](/docs/guides/llms.md)

## Account

[Automated Top-UpsTop up your API Key balance automatically when it runs low](/docs/guides/automated-topups.md)[Purchasing LookupsBuy a one-off batch of lookups, and how batches expire](/docs/guides/purchasing-lookups.md)[SublicensingLicense several organizations under one Key, billed to your account](/docs/guides/sublicensing.md)

## Security

[API Key SecurityChoose the right controls for a frontend or backend integration](/docs/guides/api-key-secure.md)[API Key SettingsDaily and individual lookup limits, IP address forwarding and log retention](/docs/guides/api-key-settings.md)[Allowed URLsRestrict a browser key to your own domains](/docs/guides/allowed-urls.md)

## API

[Error CodesEvery API error code by HTTP status, with what raises it and how to fix it.](/docs/guides/error-codes.md)[Tagging and Usage TrackingLabel requests with metadata, then query or download your lookup history](/docs/guides/tag-and-track.md)[CLISearch, verify and manage keys from the terminal with `azn`](/docs/cli.md)[OpenAPI SpecificationThe machine-readable description of every endpoint, for codegen and tooling](/docs/libraries/open-api.md)[ChangelogWhat changed in the API, widgets and dashboard, by date](/docs/changelog.md)

## Migrate

[Switch from GoogleReplace Place Autocomplete and Address Validation with one script, in three steps](/docs/how-to-switch.md)

## Legal

[Data ProcessingHow GDPR applies to us as your data processor](/docs/guides/data.md)

Need help? [Contact our support team](https://addresszen.com/support) if you have a question these guides do not answer.