> For the complete documentation index, see [llms.txt](https://guide.hardfin.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guide.hardfin.com/advanced-options/api-access.md).

# API access

Hardfin's API lets your own software and your AI assistants read and change your Hardfin records.

| To                                                        | Use                                                                     |
| --------------------------------------------------------- | ----------------------------------------------------------------------- |
| Read the API reference                                    | The [Hardfin API documentation](https://docs.hardfin.com/)              |
| Point an AI assistant or coding tool at the API reference | The [API reference for agents](https://developers.hardfin.com/llms.txt) |
| Connect an AI assistant such as Claude or ChatGPT         | [Connect AI assistants](/advanced-options/ai-assistants.md)             |
| Work with Hardfin from a terminal                         | The [Hardfin CLI](https://www.npmjs.com/package/@hardfin/cli)           |
| Teach an AI assistant how to work with Hardfin            | The [Hardfin skills](https://github.com/hardfinhq/skills)               |

## API keys

API keys let your own software call the API without signing in. Your organization's keys are listed in the **API keys** section of the [integrations page](https://assets.hardfin.com/integrations). For each key, you can see its name, its public value, and its access level:

* **Can read**: the key can view records in your organization
* **Can read and change**: the key can view, create, and change records in your organization

A key's secret value is only shown when the key is created. To add a key or change a key's access level, contact your Customer Success representative.

API keys belong to a person in your organization. If that person is removed from the organization or deactivated, their API keys stop working right away, so offboarding a user also ends any API access tied to them.

## Connected applications

Applications such as AI assistants connect to Hardfin on your behalf after you sign in and approve them. [Connect AI assistants](/advanced-options/ai-assistants.md) describes how to connect one, how to choose its access level, and how to disconnect it.