> For a complete index of all SignalWire documentation pages, fetch https://signalwire.com/docs/llms.txt # Environment Variables > Complete reference for all environment variables used by the SignalWire Server SDK. [ref-relayclient]: /docs/server-sdks/reference/python/relay/client The SignalWire Server SDK reads environment variables for server configuration, authentication, SSL, logging, Relay/REST client credentials, and serverless platform detection. Environment variables are overridden by constructor parameters but take precedence over config file values. Use `python-dotenv` to load variables from a `.env` file during development: ```python from dotenv import load_dotenv load_dotenv() from signalwire import AgentBase agent = AgentBase(name="my-agent") ``` --- ## Server **`PORT`** `int` — default: 3000 Server port. Used when no `port` argument is passed to the constructor. --- ## Authentication **`SWML_BASIC_AUTH_USER`** `str` Username for HTTP Basic Authentication on all agent webhook endpoints. If not set, `get_basic_auth()` defaults the username to `"signalwire"`. --- **`SWML_BASIC_AUTH_PASSWORD`** `str` Password for HTTP Basic Authentication. If not set, a random password is auto-generated on each startup and printed to the console. --- In production, always set `SWML_BASIC_AUTH_PASSWORD` explicitly. Auto-generated passwords change on every restart, which will break SignalWire webhook callbacks until you update the credentials in your SignalWire dashboard. --- ## SSL / TLS **`SWML_SSL_ENABLED`** `bool` — default: false Enable HTTPS. Accepts `"true"`, `"1"`, or `"yes"`. --- **`SWML_SSL_CERT_PATH`** `str` Path to the SSL certificate file (`.pem` or `.crt`). Required when `SWML_SSL_ENABLED` is set. --- **`SWML_SSL_KEY_PATH`** `str` Path to the SSL private key file (`.key`). Required when `SWML_SSL_ENABLED` is set. --- **`SWML_DOMAIN`** `str` Domain name for SSL certificates and URL generation. --- **`SWML_SSL_VERIFY_MODE`** `str` — default: CERT\_REQUIRED SSL certificate verification mode. --- ## Proxy **`SWML_PROXY_URL_BASE`** `str` Base URL when running behind a reverse proxy (e.g., `https://my-agent.example.com`). The agent uses this URL to generate correct webhook URLs in SWML documents. --- **`APP_URL`** `str` Fallback for `SWML_PROXY_URL_BASE` when that variable is not set. --- **`SWML_PROXY_DEBUG`** `bool` — default: false Enable proxy request debug logging. --- Setting `SWML_PROXY_URL_BASE` (or `APP_URL`) overrides SSL configuration and port settings for webhook URL generation. --- ## Schema Validation **`SWML_SKIP_SCHEMA_VALIDATION`** `bool` — default: false Disable SWML document schema validation. Accepts `"1"`, `"true"`, or `"yes"`. Useful for performance in production when you trust your SWML output. --- ## Security **`SWML_ALLOWED_HOSTS`** `str` — default: \* Comma-separated list of allowed hosts. Set to specific domain(s) in production (e.g., `"agent.example.com,api.example.com"`). --- **`SWML_CORS_ORIGINS`** `str` — default: \* Comma-separated list of allowed CORS origins. Restrict to trusted origins in production. --- **`SWML_MAX_REQUEST_SIZE`** `int` — default: 10485760 Maximum request body size in bytes. Default is 10 MB. --- **`SWML_RATE_LIMIT`** `int` — default: 60 Rate limit in requests per minute. --- **`SWML_REQUEST_TIMEOUT`** `int` — default: 30 Request timeout in seconds. --- **`SWML_USE_HSTS`** `bool` — default: true Enable HTTP Strict Transport Security headers when serving over HTTPS. --- **`SWML_HSTS_MAX_AGE`** `int` — default: 31536000 HSTS `max-age` directive in seconds. Default is 1 year. --- ## Logging **`SIGNALWIRE_LOG_MODE`** `str` — default: auto Logging mode. * `"auto"` -- automatic detection based on environment * `"off"` -- disable all logging * `"stderr"` -- log to stderr * `"default"` -- standard logging output --- **`SIGNALWIRE_LOG_LEVEL`** `str` — default: info Log level. * `"debug"` -- verbose output for development and troubleshooting * `"info"` -- standard operational messages * `"warning"` -- potential issues that do not prevent operation * `"error"` -- failures that affect a specific operation * `"critical"` -- severe failures that may prevent the service from running --- **`SIGNALWIRE_LOG_FORMAT`** `str` — default: console Log output format. * `"console"` -- colored human-readable output (default) * `"json"` -- structured JSON log lines for log aggregation systems --- ## Skills **`SIGNALWIRE_SKILL_PATHS`** `str` Colon-separated paths to directories containing custom skills. The skill registry scans these paths in addition to the built-in skills directory. --- ## Relay and REST Client These variables are shared between the Relay WebSocket client and the REST HTTP client. **`SIGNALWIRE_PROJECT_ID`** `str` SignalWire project ID for authentication. --- **`SIGNALWIRE_API_TOKEN`** `str` API token for authentication. --- **`SIGNALWIRE_JWT_TOKEN`** `str` JWT token for Relay authentication. Alternative to project ID + API token. --- **`SIGNALWIRE_SPACE`** `str` — default: relay.signalwire.com Space hostname used for Relay WebSocket connections and as the REST API base URL. --- **`RELAY_MAX_ACTIVE_CALLS`** `int` — default: 1000 Maximum concurrent calls per [`RelayClient`][ref-relayclient] instance. --- **`RELAY_MAX_CONNECTIONS`** `int` — default: 1 Maximum concurrent `RelayClient` connections per process. --- ## Serverless Platforms The SDK auto-detects the execution environment from platform-specific variables. You typically do not set these manually -- they are provided by the platform runtime. ### AWS Lambda **`AWS_LAMBDA_FUNCTION_NAME`** `str` — default: unknown Lambda function name. Used for URL construction and logging. --- **`AWS_LAMBDA_FUNCTION_URL`** `str` Lambda function URL. If not set, constructed from region and function name. --- **`AWS_REGION`** `str` — default: us-east-1 AWS region for Lambda execution. --- **`LAMBDA_TASK_ROOT`** `str` Lambda environment detection variable. Set automatically by the Lambda runtime. --- ### Google Cloud Functions **`GOOGLE_CLOUD_PROJECT`** `str` Google Cloud project ID. --- **`GCP_PROJECT`** `str` Alternative to `GOOGLE_CLOUD_PROJECT`. --- **`GOOGLE_CLOUD_REGION`** `str` — default: us-central1 Google Cloud region. --- **`FUNCTION_TARGET`** `str` — default: unknown Cloud Function entry point name. --- **`K_SERVICE`** `str` — default: unknown Knative/Cloud Run service name. --- ### Azure Functions **`AZURE_FUNCTIONS_ENVIRONMENT`** `str` Azure Functions environment detection variable. --- **`WEBSITE_SITE_NAME`** `str` Azure App Service site name. Used to construct function URLs. --- **`AZURE_FUNCTION_NAME`** `str` — default: unknown Azure Function name. --- ### CGI **`GATEWAY_INTERFACE`** `str` CGI environment detection variable. --- **`HTTP_HOST`** `str` HTTP Host header value. Falls back to `SERVER_NAME`. --- **`SERVER_NAME`** `str` — default: localhost Server hostname. --- **`SCRIPT_NAME`** `str` CGI script path. --- ## Example .env File ```bash # Server PORT=3000 # Authentication SWML_BASIC_AUTH_USER=agent_user SWML_BASIC_AUTH_PASSWORD=secret_password_123 # SSL Configuration SWML_SSL_ENABLED=true SWML_DOMAIN=agent.example.com SWML_SSL_CERT_PATH=/etc/ssl/certs/agent.crt SWML_SSL_KEY_PATH=/etc/ssl/private/agent.key # Security SWML_ALLOWED_HOSTS=agent.example.com SWML_CORS_ORIGINS=https://app.example.com SWML_RATE_LIMIT=100 # Logging SIGNALWIRE_LOG_MODE=default SIGNALWIRE_LOG_LEVEL=info # Relay / REST SIGNALWIRE_PROJECT_ID=your-project-id SIGNALWIRE_API_TOKEN=your-api-token SIGNALWIRE_SPACE=your-space.signalwire.com # Custom Skills SIGNALWIRE_SKILL_PATHS=/opt/custom_skills ``` ## Loading .env in Python ```python from dotenv import load_dotenv load_dotenv() from signalwire import AgentBase agent = AgentBase(name="my-agent") # Environment variables are now available to the SDK username, password, source = agent.get_basic_auth_credentials(include_source=True) print(f"Auth: {username}:{password} (source: {source})") ```