# Column Tax Documentation

> Column Tax API Documentation

## Guides
- [Welcome to Column Tax!](https://docs.columntax.com/docs/welcome.md)
- [Quick start](https://docs.columntax.com/docs/quick-start.md): How to integrate Column Tax
- [API access](https://docs.columntax.com/docs/api-access.md)
- [Create a Column Tax user](https://docs.columntax.com/docs/create-user-guide.md)
- [Launch the Column Tax UI](https://docs.columntax.com/docs/launch-ui-guide.md): How to programmatically open up the Column Tax UI embedded within your app
- [Build your Tax hub](https://docs.columntax.com/docs/tax-hub-guide.md)
- [Run re-engagement campaigns](https://docs.columntax.com/docs/run-campaigns-guide.md)
- [FAQs](https://docs.columntax.com/docs/faqs.md)
- [Sample code](https://docs.columntax.com/docs/sample-code.md)

## API Reference
- [Environments](https://docs.columntax.com/reference/environments.md)
- [Authentication and Headers](https://docs.columntax.com/reference/authentication.md)
- [Errors and Rate Limits](https://docs.columntax.com/reference/errors-rate-limits.md)
- [User URLs](https://docs.columntax.com/reference/users-tokens.md)
- [Initialize Tax Filing](https://docs.columntax.com/reference/express-initialize-tax-filing.md)
- [Tax Returns](https://docs.columntax.com/reference/tax-returns.md): Get a list of a user's Tax Returns
- [Sample test users](https://docs.columntax.com/reference/sample-users.md)
- [Webhook Events](https://docs.columntax.com/reference/webhook-events.md): Listen for user and tax return events
- [Mobile SDK Reference](https://docs.columntax.com/reference/mobile-sdk-guide.md): Guide to using our iOS, Android, and React Native mobile SDKs