Configuration

Complete guide to Cal.com environment variables and configuration options

Cal.com is configured primarily through environment variables defined in a .env file. This guide documents all available configuration options.

Quick Setup

1. Copy the example environment file:

cp .env.example .env

2. Generate required secrets:

# NextAuth secret (32 bytes)
openssl rand -base64 32

# Encryption key (24 bytes for AES256)
openssl rand -base64 24

# VAPID keys for push notifications
npx web-push generate-vapid-keys

3. Configure essential variables in .env

Essential Configuration

Database

DATABASE_URL · string · required

PostgreSQL connection string with credentials. Used by the application and connection poolers.

DATABASE_URL="postgresql://postgres:password@localhost:5432/calendso"

DATABASE_DIRECT_URL · string · required

Direct PostgreSQL connection for migrations. Use the same as DATABASE_URL if not using a connection pooler like PgBouncer.

DATABASE_DIRECT_URL="postgresql://postgres:password@localhost:5432/calendso"

INSIGHTS_DATABASE_URL · string

Optional separate database for analytics and insights data.

PGSSLMODE · string · default: "prefer"

SSL mode for PostgreSQL connection. Use no-verify for self-signed certificates (Heroku, etc.).

PGSSLMODE="no-verify"

Application URLs

NEXT_PUBLIC_WEBAPP_URL · string · required

Base URL where your Cal.com instance is hosted. Must include protocol.

NEXT_PUBLIC_WEBAPP_URL="https://cal.yourdomain.com"

For organizations feature, use app subdomain: http://app.cal.local:3000

NEXT_PUBLIC_WEBSITE_URL · string

Marketing website URL. Defaults to NEXT_PUBLIC_WEBAPP_URL.

NEXT_PUBLIC_WEBSITE_URL="https://yourdomain.com"

NEXT_PUBLIC_EMBED_LIB_URL · string

URL for Cal.com embed library.

NEXT_PUBLIC_EMBED_LIB_URL="http://localhost:3000/embed/embed.js"

Authentication (NextAuth)

NEXTAUTH_URL · string · required

Full URL to NextAuth API endpoint. Required for Vercel deployments.

NEXTAUTH_URL="https://cal.yourdomain.com"

NEXTAUTH_SECRET · string · required

Secret for encrypting session cookies. Generate with openssl rand -base64 32.

NEXTAUTH_SECRET="your-generated-secret-here"

NEXTAUTH_COOKIE_DOMAIN · string

Domain for cross-domain cookie authentication.

NEXTAUTH_COOKIE_DOMAIN=".yourdomain.com"

Encryption

CALENDSO_ENCRYPTION_KEY · string · required

32-byte key for AES256 encryption. Generate with openssl rand -base64 24.

CALENDSO_ENCRYPTION_KEY="your-24-character-key"

CALCOM_APP_CREDENTIAL_ENCRYPTION_KEY · string

24-byte key for app credential encryption in credential sync.

CALCOM_APP_CREDENTIAL_ENCRYPTION_KEY="$(openssl rand -base64 24)"

CALCOM_SERVICE_ACCOUNT_ENCRYPTION_KEY · string

24-byte key for service account encryption.

CALCOM_SERVICE_ACCOUNT_ENCRYPTION_KEY="$(openssl rand -base64 24)"

Security

Content Security Policy

CSP_POLICY · string

Enable Content Security Policy. Set to non-strict for enhanced security.

CSP_POLICY="non-strict"

Strict CSP enables on login pages; report-only mode on SSR pages

Rate Limiting

UNKEY_ROOT_KEY · string

Root key from Unkey for rate limiting. Optional but recommended for production.

Requires permissions: ratelimit.create_namespace and ratelimit.limit

Allowed Hostnames

ALLOWED_HOSTNAMES · string

JSON array of allowed hostnames for the application.

ALLOWED_HOSTNAMES='"cal.com","cal.dev","localhost:3000"'

RESERVED_SUBDOMAINS · string

Reserved organization subdomain names.

RESERVED_SUBDOMAINS='"app","auth","docs","api","www"'

Email Configuration

SMTP Settings

EMAIL_FROM · string · required

Sender email address for all outgoing emails.

EMAIL_FROM="[e-mail]"

EMAIL_FROM_NAME · string

Display name for sender.

EMAIL_FROM_NAME="Cal.com"

EMAIL_SERVER_HOST · string · required

SMTP server hostname.

# Gmail
EMAIL_SERVER_HOST="smtp.gmail.com"

# Office 365
EMAIL_SERVER_HOST="smtp.office365.com"

# Local development (Mailhog)
EMAIL_SERVER_HOST="localhost"

EMAIL_SERVER_PORT · number · required

SMTP server port.

EMAIL_SERVER_PORT=587  # TLS
EMAIL_SERVER_PORT=465  # SSL (Gmail)
EMAIL_SERVER_PORT=1025 # Mailhog (development)

EMAIL_SERVER_USER · string

SMTP authentication username.

EMAIL_SERVER_PASSWORD · string

SMTP authentication password or app-specific password.

SendGrid

SENDGRID_API_KEY · string

SendGrid API key for transactional emails and reminders.

SENDGRID_API_KEY="SG.xxxxxxxxxxxx"

SENDGRID_EMAIL · string

Verified sender email in SendGrid.

SENDGRID_EMAIL="[e-mail]"

NEXT_PUBLIC_SENDGRID_SENDER_NAME · string

Display name for SendGrid emails.

NEXT_PUBLIC_SENDGRID_SENDER_NAME="Cal.com Notifications"

Resend

RESEND_API_KEY · string

Resend API key for transactional emails (alternative to SendGrid).

RESEND_API_KEY="re_xxxxxxxxxxxx"

License & Enterprise

CALCOM_LICENSE_KEY · string

Enterprise license key. Required for enterprise features.

CALCOM_LICENSE_KEY="your-license-key"

CAL_SIGNATURE_TOKEN · string

Signature token for Cal.com License API authentication.

CALCOM_PRIVATE_API_ROUTE · string · default: "https://goblin.cal.com"

Route to Cal.com License API.

Integrations

Google Calendar

GOOGLE_API_CREDENTIALS · json

Google OAuth credentials JSON for Calendar and Meet integration.

GOOGLE_API_CREDENTIALS='{"web":{"client_id":"...","client_secret":"..."}}'

See Obtaining Google API Credentials for setup instructions.

GOOGLE_LOGIN_ENABLED · boolean · default: "false"

Enable “Sign in with Google”.

GOOGLE_LOGIN_ENABLED=true

Configure as Internal app to prevent unauthorized access

GOOGLE_CALENDAR_API_KEY · string

Google Calendar API key for holidays feature.

GOOGLE_WEBHOOK_TOKEN · string

Token to verify incoming webhooks from Google Calendar.

GOOGLE_WEBHOOK_URL · string

Override URL for Google Calendar webhooks. Defaults to NEXT_PUBLIC_WEBAPP_URL.

Microsoft 365

MS_GRAPH_CLIENT_ID · string

Microsoft Graph Application (client) ID.

MS_GRAPH_CLIENT_SECRET · string

Microsoft Graph client secret.

MICROSOFT_WEBHOOK_TOKEN · string

Token to verify incoming webhooks from Microsoft Calendar.

MICROSOFT_WEBHOOK_URL · string

Override URL for Microsoft Calendar webhooks.

Zoom

ZOOM_CLIENT_ID · string

Zoom OAuth client ID.

ZOOM_CLIENT_SECRET · string

Zoom OAuth client secret.

Daily.co Video

DAILY_API_KEY · string

Daily.co API key for video conferencing.

DAILY_SCALE_PLAN · boolean · default: "false"

Enable Daily Scale Plan features (recording, etc.).

DAILY_SCALE_PLAN=true

Stripe

STRIPE_PRIVATE_KEY · string

Stripe secret key for payment processing.

STRIPE_CLIENT_ID · string

Stripe client ID for Connect.

STRIPE_WEBHOOK_SECRET · string

Stripe webhook signing secret.

STRIPE_WEBHOOK_SECRET_APPS · string

Stripe webhook secret for app store integrations.

SMS & WhatsApp

Twilio

TWILIO_SID · string

Twilio Account SID.

TWILIO_TOKEN · string

Twilio Auth Token.

TWILIO_MESSAGING_SID · string

Twilio Messaging Service SID.

TWILIO_PHONE_NUMBER · string

Twilio phone number for SMS.

TWILIO_PHONE_NUMBER="[phone]"

TWILIO_WHATSAPP_PHONE_NUMBER · string

Twilio WhatsApp-enabled phone number.

TWILIO_WHATSAPP_PHONE_NUMBER="whatsapp:[phone]"

NEXT_PUBLIC_SENDER_ID · string

SMS sender ID (max 11 characters, letters, numbers, and spaces only).

TWILIO_VERIFY_SID · string

Twilio Verify Service SID for phone verification.

Push Notifications

NEXT_PUBLIC_VAPID_PUBLIC_KEY · string · required

VAPID public key for browser push notifications.

Generate with: npx web-push generate-vapid-keys

NEXT_PUBLIC_VAPID_PUBLIC_KEY="BKxxx..."

VAPID_PRIVATE_KEY · string · required

VAPID private key for push notifications.

VAPID_PRIVATE_KEY="xxx..."

Branding & Customization

NEXT_PUBLIC_APP_NAME · string · default: "Cal.com"

Application name displayed throughout the UI.

NEXT_PUBLIC_APP_NAME="Your Company Scheduler"

NEXT_PUBLIC_SUPPORT_MAIL_ADDRESS · string · default: "[e-mail]"

Support email address.

NEXT_PUBLIC_SUPPORT_MAIL_ADDRESS="[e-mail]"

NEXT_PUBLIC_COMPANY_NAME · string · default: "Cal.com, Inc."

Company name for legal pages.

NEXT_PUBLIC_COMPANY_NAME="Your Company, Inc."

NEXT_PUBLIC_WEBSITE_PRIVACY_POLICY_URL · string

URL to your privacy policy.

NEXT_PUBLIC_WEBSITE_PRIVACY_POLICY_URL="https://yourdomain.com/privacy"

NEXT_PUBLIC_WEBSITE_TERMS_URL · string

URL to your terms of service.

NEXT_PUBLIC_WEBSITE_TERMS_URL="https://yourdomain.com/terms"

NEXT_PUBLIC_DISABLE_SIGNUP · boolean · default: "false"

Disable new user signups.

NEXT_PUBLIC_DISABLE_SIGNUP=true

Analytics & Monitoring

Telemetry

CALCOM_TELEMETRY_DISABLED · boolean · default: "false"

Disable anonymous usage analytics.

CALCOM_TELEMETRY_DISABLED=1

Sentry

NEXT_PUBLIC_SENTRY_DSN · string

Sentry DSN for error tracking.

NEXT_PUBLIC_SENTRY_DSN="https://[e-mail]/xxx"

SENTRY_ORG · string

Sentry organization slug.

SENTRY_PROJECT · string

Sentry project name.

SENTRY_AUTH_TOKEN · string

Sentry authentication token for releases.

PostHog

NEXT_PUBLIC_POSTHOG_KEY · string

PostHog project API key.

NEXT_PUBLIC_POSTHOG_HOST · string

PostHog instance URL.

NEXT_PUBLIC_POSTHOG_HOST="https://app.posthog.com"

Logging

NEXT_PUBLIC_LOGGER_LEVEL · number

Logging verbosity level:

• 0: silly & upwards
• 1: trace & upwards
• 2: debug & upwards
• 3: info & upwards (recommended)
• 4: warn & upwards
• 5: error & fatal
• 6: fatal only

NEXT_PUBLIC_LOGGER_LEVEL=3

Organizations (Enterprise)

ORGANIZATIONS_ENABLED · boolean · default: "false"

Enable organizations feature (requires full domain setup).

ORGANIZATIONS_ENABLED=true
NEXT_PUBLIC_WEBAPP_URL="http://app.cal.local:3000"

NEXT_PUBLIC_SINGLE_ORG_SLUG · string

Serve only one organization’s booking pages.

NEXT_PUBLIC_SINGLE_ORG_SLUG="your-org"

ORGANIZATIONS_AUTOLINK · boolean · default: "false"

Auto-link external signups to organizations by email domain.

NEXT_PUBLIC_ORGANIZATIONS_MIN_SELF_SERVE_SEATS · number · default: "30"

Minimum seats for self-serve organizations.

Vercel Domain Management

PROJECT_ID_VERCEL · string

Vercel project ID for subdomain management.

TEAM_ID_VERCEL · string

Vercel team ID.

AUTH_BEARER_TOKEN_VERCEL · string

Vercel API token for domain management.

Cloudflare DNS Management

CLOUDFLARE_DNS · boolean · default: "false"

Use Cloudflare for DNS management.

CLOUDFLARE_DNS=1

AUTH_BEARER_TOKEN_CLOUDFLARE · string

Cloudflare API token with Zone Edit permissions.

CLOUDFLARE_ZONE_ID · string

Cloudflare Zone ID for your domain.

CLOUDFLARE_VERCEL_CNAME · string · default: "cname.vercel-dns.com"

CNAME target for Vercel domains.

SAML SSO (Enterprise)

SAML_DATABASE_URL · string

Separate PostgreSQL database for SAML data.

SAML_DATABASE_URL="postgresql://user:pass@host:5432/cal-saml"

SAML_ADMINS · string

Comma-separated list of admin emails.

SAML_ADMINS="[e-mail],[e-mail]"

SAML_CLIENT_SECRET_VERIFIER · string

Random secret for OAuth 2.0 SAML flow.

API V2

NEXT_PUBLIC_API_V2_URL · string

URL for Cal.com Platform API v2.

NEXT_PUBLIC_API_V2_URL="http://localhost:5555/api/v2"

API_PORT · number · default: "80"

Port for API v2 service.

API_PORT=5555

API_URL · string

Full URL to API v2 service.

WEB_APP_URL · string

Web application URL for API callbacks.

API_KEY_PREFIX · string · default: "cal_"

Prefix for API keys.

API_KEY_PREFIX="cal_"

Cron Jobs

CRON_API_KEY · string · required

API key for authenticating cron job requests.

CRON_API_KEY="$(openssl rand -hex 16)"

CRON_ENABLE_APP_SYNC · boolean · default: "false"

Auto-sync app metadata from config files.

CRON_ENABLE_APP_SYNC=true

Redis

REDIS_URL · string

Redis connection string for caching and queues.

REDIS_URL="redis://localhost:6379"

REDIS_PORT · number · default: "6379"

Redis port (used in docker-compose).

Performance & Optimization

NODE_OPTIONS · string

Node.js runtime options.

NODE_OPTIONS="--max-old-space-size=16384"

MAX_OLD_SPACE_SIZE · number · default: "6144"

Memory limit for build process (in MB).

DATABASE_CHUNK_SIZE · number

Batch size for database operations.

TZ · string · default: "UTC"

Process timezone. Always use UTC.

TZ=UTC

Development & Testing

NODE_ENV · string

Node environment.

NODE_ENV="production"  # or "development"

NEXT_PUBLIC_IS_E2E · boolean · default: "false"

Enable E2E testing mode.

NEXT_PUBLIC_IS_E2E=1

E2E_TEST_MAILHOG_ENABLED · boolean · default: "false"

Enable Mailhog for email testing.

E2E_TEST_MAILHOG_ENABLED=1

Example Configurations

Minimal Production Setup

# Database
DATABASE_URL="postgresql://user:[e-mail]:5432/calendso"
DATABASE_DIRECT_URL="postgresql://user:[e-mail]:5432/calendso"

# URLs
NEXT_PUBLIC_WEBAPP_URL="https://cal.yourdomain.com"
NEXTAUTH_URL="https://cal.yourdomain.com"

# Secrets (generate these!)
NEXTAUTH_SECRET="generated-with-openssl-rand"
CALENDSO_ENCRYPTION_KEY="generated-24-byte-key"
CRON_API_KEY="generated-cron-key"

# VAPID (generate with npx web-push generate-vapid-keys)
NEXT_PUBLIC_VAPID_PUBLIC_KEY="your-public-key"
VAPID_PRIVATE_KEY="your-private-key"

# Email
EMAIL_FROM="[e-mail]"
SENDGRID_API_KEY="SG.xxxxx"
SENDGRID_EMAIL="[e-mail]"

# Disable telemetry
CALCOM_TELEMETRY_DISABLED=1

Docker Compose Setup

# Docker-managed services
DATABASE_URL="postgresql://unicorn_user:magical_password@database:5432/calendso"
REDIS_URL="redis://redis:6379"

# Application
NEXT_PUBLIC_WEBAPP_URL="http://localhost:3000"
NEXTAUTH_URL="http://localhost:3000"
NEXTAUTH_SECRET="secret-for-dev"
CALENDSO_ENCRYPTION_KEY="encryption-key-for-dev"

# VAPID keys
NEXT_PUBLIC_VAPID_PUBLIC_KEY="your-public-key"
VAPID_PRIVATE_KEY="your-private-key"

# Email (development with Mailhog)
EMAIL_SERVER_HOST="localhost"
EMAIL_SERVER_PORT=1025
EMAIL_FROM="[e-mail]"

Enterprise with Organizations

# Enable organizations
ORGANIZATIONS_ENABLED=true
NEXT_PUBLIC_WEBAPP_URL="https://app.yourcompany.com"

# License
CALCOM_LICENSE_KEY="your-enterprise-license"
CAL_SIGNATURE_TOKEN="your-signature-token"

# SAML SSO
SAML_DATABASE_URL="postgresql://user:pass@host:5432/cal-saml"
SAML_ADMINS="[e-mail]"

# Domain management (Cloudflare)
CLOUDFLARE_DNS=1
AUTH_BEARER_TOKEN_CLOUDFLARE="your-api-token"
CLOUDFLARE_ZONE_ID="your-zone-id"

Next Steps

• Review Database Setup for connection pooling and migrations
• See Docker Configuration for container-specific options
• Configure Deployment for your platform