> ## Documentation Index
> Fetch the complete documentation index at: https://docs.district79.school/llms.txt
> Use this file to discover all available pages before exploring further.

# Environment variables

> Required and optional secrets for local and Vercel environments.

Copy the sample file at the repo root:

```bash theme={null}
cp .env.example .env.local
```

<Callout type="danger">
  Never commit `.env.local` or paste production secrets into docs, tickets, or chat. Rotate any credential that has been exposed.
</Callout>

## Required

```bash theme={null} theme={null}
# MongoDB (Atlas recommended)
MONGODB_URI=mongodb+srv://USER:PASSWORD@CLUSTER/d79-directory?retryWrites=true&w=majority

# NextAuth
NEXTAUTH_URL=http://localhost:3000
NEXTAUTH_SECRET=generate-a-long-random-string

# Google OAuth Web client
GOOGLE_CLIENT_ID=xxxxx.apps.googleusercontent.com
GOOGLE_CLIENT_SECRET=GOCSPX-xxxxx
```

Generate `NEXTAUTH_SECRET`:

```bash theme={null}
openssl rand -base64 32
```

## Optional

```bash theme={null} theme={null}
# Required in production (locks, cache, save rate limits, logout revoke, admin rate limits)
REDIS_URL=redis://default:PASSWORD@HOST:PORT

# Optional API error reporting (do not send form answers to Sentry)
SENTRY_DSN=
```

Without `REDIS_URL`, locks and caches are in-memory per serverless isolate and will not coordinate across instances.

Super Admins can confirm whether these variables are **set** (not their values) on [System health](/features/system).

## Google redirect URIs

<Tabs>
  <Tab title="Local">
    `http://localhost:3000/api/auth/callback/google`
  </Tab>

  <Tab title="Production">
    `https://<your-domain>/api/auth/callback/google`

    Set `NEXTAUTH_URL` to the same origin, including `https://`, with no path (trailing slash is tolerated but avoid duplicates in Google Console).
  </Tab>
</Tabs>

## Vercel

Add the same keys in **Project → Settings → Environment Variables** for Production, Preview, and Development as needed. Redeploy after changing `NEXTAUTH_URL` or OAuth clients.

![Vercel env UI](https://placehold.co/600x400)
*Caption: Add screenshot showing Vercel environment variables for MONGODB\_URI, NEXTAUTH\_URL, NEXTAUTH\_SECRET, GOOGLE\_CLIENT\_ID, GOOGLE\_CLIENT\_SECRET, REDIS\_URL, SENTRY\_DSN.*