Configuration - Cal.com

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

Quick Setup

Copy the example environment file:

cp .env.example .env

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

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"

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="[email protected]"

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="[email protected]"

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.

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="+1234567890"

TWILIO_WHATSAPP_PHONE_NUMBER

string

Twilio WhatsApp-enabled phone number.

TWILIO_WHATSAPP_PHONE_NUMBER="whatsapp:+1234567890"

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:"[email protected]"

Support email address.

NEXT_PUBLIC_SUPPORT_MAIL_ADDRESS="[email protected]"

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"

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://[email protected]/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="[email protected],[email protected]"

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.

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:[email protected]:5432/calendso"
DATABASE_DIRECT_URL="postgresql://user:[email protected]: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="[email protected]"
SENDGRID_API_KEY="SG.xxxxx"
SENDGRID_EMAIL="[email protected]"

# 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="[email protected]"

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="[email protected]"

# 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

Get Started

Core Features

Integrations

Embedding

Self-Hosting

Enterprise

​Quick Setup

​Essential Configuration

​Database

​Application URLs

​Authentication (NextAuth)

​Encryption

​Security

​Content Security Policy

​Rate Limiting

​Allowed Hostnames

​Email Configuration

​SMTP Settings

​SendGrid

​Resend

​License & Enterprise

​Integrations

​Google Calendar

​Microsoft 365

​Zoom

​Daily.co Video

​Stripe

​SMS & WhatsApp

​Twilio

​Push Notifications

​Branding & Customization

​Analytics & Monitoring

​Telemetry

​Sentry

​PostHog

​Logging

​Organizations (Enterprise)

​Vercel Domain Management

​Cloudflare DNS Management

​SAML SSO (Enterprise)

​API V2

​Cron Jobs

​Redis

​Performance & Optimization

​Development & Testing

​Example Configurations

​Minimal Production Setup

​Docker Compose Setup

​Enterprise with Organizations

​Next Steps

Build docs developers (and LLMs) love

Quick Setup

Essential Configuration

Database

Application URLs

Authentication (NextAuth)

Encryption

Security

Content Security Policy

Rate Limiting

Allowed Hostnames

Email Configuration

SMTP Settings

SendGrid

Resend

License & Enterprise

Integrations

Google Calendar

Microsoft 365

Zoom

Daily.co Video

Stripe

SMS & WhatsApp

Twilio

Push Notifications

Branding & Customization

Analytics & Monitoring

Telemetry

Sentry

PostHog

Logging

Organizations (Enterprise)

Vercel Domain Management

Cloudflare DNS Management

SAML SSO (Enterprise)

API V2

Cron Jobs

Redis

Performance & Optimization

Development & Testing

Example Configurations

Minimal Production Setup

Docker Compose Setup

Enterprise with Organizations

Next Steps