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

# Secrets

> Store the credentials Fimo uses for webhooks, schedules, and agents.

Secrets are credentials Fimo itself uses: webhook headers, schedule runs, and agents. Your site never receives them. For an API key your site's code calls with, use a [private variable](/docs/studio/variables.md).

Open **Settings** → **Advanced settings** → **Secrets**. Only site members with **Full Access** can add, replace, or remove secrets.

The page shows all readable environments together. Each row is one key and Environment pair, with the Environment shown as a badge, so you can compare Production, Preview, and custom Environments without switching a page-level filter. Fimo hides each value after you save it.

![Secrets in site settings](https://assets.fimo.ai/cdn-cgi/image/width=1280,fit=scale-down,quality=85,format=auto/docs/studio/secrets-desktop-20260725.png)

## Add a secret

Choose **Add secret**, select the Environment it applies to, enter an uppercase key such as `RESEND_API_KEY`, then enter its value. Add the same key again when another Environment needs its own value. You will not be able to view the value again after saving it.

![Adding a site secret](https://assets.fimo.ai/cdn-cgi/image/width=390,fit=scale-down,quality=85,format=auto/docs/studio/secrets-mobile-20260725.png)

Use the row menu to replace a secret value or delete the secret. Replacing a value keeps the same key, so integrations can continue referring to it.

> [!WARNING]
>
> Secret keys cannot start with `PUBLIC_`, `VITE_`, `NEXT_PUBLIC_`, or `NUXT_PUBLIC_`. Those prefixes can expose values
> to browser code.

## Use secrets in integrations

When configuring a webhook header, insert an existing secret into a value such as `Bearer RESEND_API_KEY`. The secret stays hidden in Studio and in delivery history.

Developers and coding agents can manage the same secrets with [`fimo secrets`](/docs/reference/cli).

> [card] [Webhooks](/docs/studio/webhooks.md)
>
> Send site events to services that use your secrets.

> [card] [CLI reference](/docs/reference/cli.md#project-variables-secrets)
>
> Manage site secrets from a terminal or coding agent.


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.