Environment Variables

Overview

Environment variables allow you to store secrets, API keys, and configuration outside your code. Supabase provides both built-in environment variables and custom secrets management.

Never commit secrets to version control. Always use environment variables for sensitive data.

Built-in Environment Variables

Supabase automatically provides these environment variables to all functions:

Variable	Description	Example
`SUPABASE_URL`	Your project’s API URL	`https://xxx.supabase.co`
`SUPABASE_ANON_KEY`	Your project’s anon key	`eyJhbGc...`
`SUPABASE_SERVICE_ROLE_KEY`	Service role key (use with caution)	`eyJhbGc...`
`SUPABASE_DB_URL`	PostgreSQL connection string	`postgresql://...`

Access Built-in Variables

Deno.serve(async (req) => {
  // Access built-in variables
  const supabaseUrl = Deno.env.get('SUPABASE_URL')
  const supabaseKey = Deno.env.get('SUPABASE_ANON_KEY')
  
  console.log('Project URL:', supabaseUrl)
  
  return new Response('OK')
})

Built-in variables are automatically configured and don’t need to be set manually.

Custom Environment Variables

Set Secrets

Set custom secrets using the CLI:

supabase secrets set OPENAI_API_KEY=sk-proj-xxx

Set multiple secrets:

supabase secrets set OPENAI_API_KEY=sk-proj-xxx STRIPE_SECRET=sk_test_xxx

Set from File

Set multiple secrets from a file:

# Create secrets file
cat > .env.production << EOF
OPENAI_API_KEY=sk-proj-xxx
STRIPE_SECRET=sk_test_xxx
RESEND_API_KEY=re_xxx
EOF

# Set all secrets at once
supabase secrets set --env-file .env.production

Don’t commit .env.production or any secrets file to git. Add them to .gitignore.

List Secrets

View all configured secrets (values are hidden):

supabase secrets list

Output:

Name                         Value (truncated)
OPENAI_API_KEY              sk-proj-***
STRIPE_SECRET               sk_test_***
RESEND_API_KEY              re_***
SUPABASE_URL                https://***
SUPABASE_ANON_KEY           eyJh***

Unset Secrets

Remove a secret:

supabase secrets unset OPENAI_API_KEY

Using Environment Variables

In Your Functions

Access environment variables with Deno.env.get():

Deno.serve(async (req) => {
  // Get environment variable
  const apiKey = Deno.env.get('OPENAI_API_KEY')
  
  if (!apiKey) {
    return new Response(
      JSON.stringify({ error: 'OPENAI_API_KEY not configured' }),
      { status: 500 }
    )
  }
  
  // Use the API key
  const response = await fetch('https://api.openai.com/v1/completions', {
    headers: {
      'Authorization': `Bearer ${apiKey}`,
      'Content-Type': 'application/json'
    },
    method: 'POST',
    body: JSON.stringify({ prompt: 'Hello' })
  })
  
  const data = await response.json()
  return new Response(JSON.stringify(data))
})

With Type Safety

Create a helper for type-safe environment variables:

// supabase/functions/_shared/env.ts
export function getEnv(key: string): string {
  const value = Deno.env.get(key)
  
  if (!value) {
    throw new Error(`Environment variable ${key} is not set`)
  }
  
  return value
}

export function getOptionalEnv(key: string, defaultValue: string): string {
  return Deno.env.get(key) ?? defaultValue
}

Use in your function:

import { getEnv, getOptionalEnv } from '../_shared/env.ts'

Deno.serve(async (req) => {
  // Will throw if not set
  const apiKey = getEnv('OPENAI_API_KEY')
  
  // Optional with default
  const model = getOptionalEnv('OPENAI_MODEL', 'gpt-3.5-turbo')
  
  // Use variables
  console.log('Using model:', model)
})

Local Development

Create Local Environment File

Create .env.local for local development:

# supabase/.env.local
OPENAI_API_KEY=sk-proj-xxx
STRIPE_SECRET=sk_test_xxx
RESEND_API_KEY=re_xxx

Add to .gitignore:

echo "supabase/.env.local" >> .gitignore

Use Local Environment Variables

Serve functions with local environment:

supabase functions serve --env-file ./supabase/.env.local

Or for all commands:

supabase start --env-file ./supabase/.env.local

Example Local Setup

Create a complete local environment:

# Copy example to actual file
cp supabase/.env.example supabase/.env.local

# Edit with your local secrets
vim supabase/.env.local

# Start services
supabase start

# Serve function with local env
supabase functions serve --env-file ./supabase/.env.local

Real-World Examples

OpenAI Integration

Securely use OpenAI API:

Deno.serve(async (req) => {
  const apiKey = Deno.env.get('OPENAI_API_KEY')
  
  if (!apiKey) {
    return new Response(
      JSON.stringify({ error: 'OpenAI API key not configured' }),
      { status: 500, headers: { 'Content-Type': 'application/json' } }
    )
  }

  const { prompt } = await req.json()

  const response = await fetch('https://api.openai.com/v1/chat/completions', {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${apiKey}`,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      model: 'gpt-4',
      messages: [{ role: 'user', content: prompt }]
    })
  })

  const data = await response.json()
  return new Response(JSON.stringify(data), {
    headers: { 'Content-Type': 'application/json' }
  })
})

Set the secret:

supabase secrets set OPENAI_API_KEY=sk-proj-xxx

Stripe Webhooks

Verify Stripe webhook signatures:

import Stripe from 'https://esm.sh/stripe@14?target=denonext'

const stripe = new Stripe(Deno.env.get('STRIPE_API_KEY') as string, {
  apiVersion: '2024-11-20'
})

const cryptoProvider = Stripe.createSubtleCryptoProvider()

Deno.serve(async (request) => {
  const signature = request.headers.get('Stripe-Signature')
  const body = await request.text()
  
  try {
    const event = await stripe.webhooks.constructEventAsync(
      body,
      signature!,
      Deno.env.get('STRIPE_WEBHOOK_SIGNING_SECRET')!,
      undefined,
      cryptoProvider
    )
    
    console.log(`Event received: ${event.id}`)
    
    // Process event
    return new Response(JSON.stringify({ ok: true }), { status: 200 })
  } catch (err) {
    console.error('Webhook signature verification failed:', err)
    return new Response(err.message, { status: 400 })
  }
})

Set secrets:

supabase secrets set STRIPE_API_KEY=sk_test_xxx
supabase secrets set STRIPE_WEBHOOK_SIGNING_SECRET=whsec_xxx

Email with Resend

Send emails securely:

const RESEND_API_KEY = Deno.env.get('RESEND_API_KEY')

Deno.serve(async (req) => {
  if (!RESEND_API_KEY) {
    return new Response('RESEND_API_KEY not configured', { status: 500 })
  }

  const { to, subject, html } = await req.json()

  const response = await fetch('https://api.resend.com/emails', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'Authorization': `Bearer ${RESEND_API_KEY}`
    },
    body: JSON.stringify({
      from: 'noreply@yourdomain.com',
      to,
      subject,
      html
    })
  })

  const data = await response.json()
  return new Response(JSON.stringify(data), {
    headers: { 'Content-Type': 'application/json' }
  })
})

Database Connection

Connect directly to PostgreSQL:

import { Pool } from 'https://deno.land/x/postgres@v0.17.0/mod.ts'

const pool = new Pool(
  {
    tls: { enabled: false },
    database: 'postgres',
    hostname: Deno.env.get('DB_HOSTNAME'),
    user: Deno.env.get('DB_USER'),
    port: 6543,
    password: Deno.env.get('DB_PASSWORD')
  },
  1
)

Deno.serve(async (_req) => {
  try {
    const connection = await pool.connect()

    try {
      const result = await connection.queryObject`SELECT * FROM animals`
      const animals = result.rows

      return new Response(JSON.stringify(animals, null, 2), {
        headers: { 'Content-Type': 'application/json' }
      })
    } finally {
      connection.release()
    }
  } catch (err) {
    console.error(err)
    return new Response(String(err?.message ?? err), { status: 500 })
  }
})

CI/CD Integration

GitHub Actions

Set secrets in GitHub Actions:

name: Deploy Functions

on:
  push:
    branches:
      - main

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      
      - uses: supabase/setup-cli@v1
        with:
          version: latest

      - name: Set secrets
        env:
          SUPABASE_ACCESS_TOKEN: ${{ secrets.SUPABASE_ACCESS_TOKEN }}
        run: |
          supabase secrets set OPENAI_API_KEY="${{ secrets.OPENAI_API_KEY }}" --project-ref ${{ secrets.PROJECT_ID }}
          supabase secrets set STRIPE_SECRET="${{ secrets.STRIPE_SECRET }}" --project-ref ${{ secrets.PROJECT_ID }}

      - name: Deploy
        env:
          SUPABASE_ACCESS_TOKEN: ${{ secrets.SUPABASE_ACCESS_TOKEN }}
        run: |
          supabase functions deploy --project-ref ${{ secrets.PROJECT_ID }}

Configure GitHub secrets:

Go to Settings > Secrets and variables > Actions
Add each secret:
- SUPABASE_ACCESS_TOKEN
- PROJECT_ID
- OPENAI_API_KEY
- STRIPE_SECRET

Environment-Specific Secrets

Use different secrets for staging and production:

- name: Deploy to staging
  if: github.ref == 'refs/heads/staging'
  run: |
    supabase secrets set OPENAI_API_KEY="${{ secrets.STAGING_OPENAI_KEY }}" --project-ref ${{ secrets.STAGING_PROJECT_ID }}
    supabase functions deploy --project-ref ${{ secrets.STAGING_PROJECT_ID }}

- name: Deploy to production
  if: github.ref == 'refs/heads/main'
  run: |
    supabase secrets set OPENAI_API_KEY="${{ secrets.PROD_OPENAI_KEY }}" --project-ref ${{ secrets.PROD_PROJECT_ID }}
    supabase functions deploy --project-ref ${{ secrets.PROD_PROJECT_ID }}

Best Practices

Never Hardcode Secrets

// Don't do this!
const apiKey = 'sk-proj-1234567890abcdef'

fetch('https://api.openai.com/v1/chat/completions', {
  headers: { 'Authorization': `Bearer ${apiKey}` }
})

// Always use environment variables
const apiKey = Deno.env.get('OPENAI_API_KEY')

if (!apiKey) {
  throw new Error('OPENAI_API_KEY not configured')
}

fetch('https://api.openai.com/v1/chat/completions', {
  headers: { 'Authorization': `Bearer ${apiKey}` }
})

Validate Environment Variables

Check variables at startup:

const REQUIRED_ENV_VARS = [
  'OPENAI_API_KEY',
  'STRIPE_SECRET',
  'RESEND_API_KEY'
]

function validateEnv() {
  const missing = REQUIRED_ENV_VARS.filter(key => !Deno.env.get(key))
  
  if (missing.length > 0) {
    throw new Error(
      `Missing required environment variables: ${missing.join(', ')}`
    )
  }
}

validateEnv()

Deno.serve(async (req) => {
  // All required variables are set
})

Use .env.example

Provide a template for developers:

# supabase/.env.example
OPENAI_API_KEY=sk-proj-your-key-here
STRIPE_SECRET=sk_test_your-secret-here
RESEND_API_KEY=re_your-key-here

Developers copy and fill in their values:

cp supabase/.env.example supabase/.env.local
# Edit .env.local with actual values

Rotate Secrets Regularly

Update secrets periodically:

# Generate new API key
# Update secret
supabase secrets set OPENAI_API_KEY=sk-proj-new-key

# Verify
supabase secrets list

Troubleshooting

Secret Not Available

If a secret isn’t available:

Check if set:
supabase secrets list
Set the secret:
supabase secrets set KEY=value

Redeploy the function:

supabase functions deploy function-name

Local vs Production Differences

If behavior differs between local and production:

Compare secrets:

# Local
cat supabase/.env.local

# Production
supabase secrets list

Ensure consistency between environments
Test with production values locally when debugging

Next Steps

Debugging

Debug and monitor your Edge Functions

Deploy Functions

Learn deployment strategies

​Overview

​Built-in Environment Variables

​Access Built-in Variables

​Custom Environment Variables

​Set Secrets

​Set from File

​List Secrets

​Unset Secrets

​Using Environment Variables

​In Your Functions

​With Type Safety

​Local Development

​Create Local Environment File

​Use Local Environment Variables

​Example Local Setup

​Real-World Examples

​OpenAI Integration

​Stripe Webhooks

​Email with Resend

​Database Connection

​CI/CD Integration

​GitHub Actions

​Environment-Specific Secrets

​Best Practices

​Never Hardcode Secrets

​Validate Environment Variables

​Use .env.example

​Rotate Secrets Regularly

​Troubleshooting

​Secret Not Available

​Local vs Production Differences

​Next Steps

Debugging

Deploy Functions

Overview

Built-in Environment Variables

Access Built-in Variables

Custom Environment Variables

Set Secrets

Set from File

List Secrets

Unset Secrets

Using Environment Variables

In Your Functions

With Type Safety

Local Development

Create Local Environment File

Use Local Environment Variables

Example Local Setup

Real-World Examples

OpenAI Integration

Stripe Webhooks

Email with Resend

Database Connection

CI/CD Integration

GitHub Actions

Environment-Specific Secrets

Best Practices

Never Hardcode Secrets

Validate Environment Variables

Use .env.example

Rotate Secrets Regularly

Troubleshooting

Secret Not Available

Local vs Production Differences

Next Steps