Configuration

Environment Variables

The API service can be configured using the following environment variables:

Variable	Default	Description
`PORT`	`3000`	HTTP server port
`HOST`	`::`	Host to bind to (supports IPv6)
`LOG_LEVEL`	`info`	Logging level (debug, info, warn, error)
`REQUEST_TIMEOUT_MS`	`8000`	Timeout for certificate fetch requests
`RATE_LIMIT_WINDOW_MS`	`60000`	Rate limit window in milliseconds
`RATE_LIMIT_MAX`	`30`	Maximum requests per rate limit window
`MAX_BODY_BYTES`	`4096`	Maximum request body size
`REVOCATION_MODE`	`ocsp`	Revocation check mode: `ocsp`, `crl`, or `off`
`CACHE_TTL_MS`	`1800000`	Cache TTL in milliseconds (default: 30 minutes)
`APP_VERSION`	`dev`	Application version string
`METRICS_ENABLED`	`false`	Enable metrics endpoint
`METRICS_API_KEY`	-	API key required to access metrics endpoint

Running from Source

Development Mode

npm run start:api:ts

Production Build

npm run build:api
npm run start:api

Configuration Example

# Set custom port and enable verbose logging
export PORT=8080
export LOG_LEVEL=debug

# Configure caching (10 minutes)
export CACHE_TTL_MS=600000

# Disable revocation checks
export REVOCATION_MODE=off

# Run the API
npm run start:api

API Configuration Endpoint

The API exposes a public configuration endpoint at GET /api/config that returns:

{
  "cacheTtlMs": 1800000,
  "revocationMode": "ocsp"
}

This endpoint is used by the extension to fetch cache settings and revocation mode.

Metrics Endpoint

The API exposes a metrics endpoint at GET /api/metrics when enabled.

Enabling Metrics

export METRICS_ENABLED=true
export METRICS_API_KEY=your-secret-key

Accessing Metrics

curl -H "X-API-Key: your-secret-key" http://localhost:3000/metrics

Response Example

{
  "totalRequests": 150,
  "successfulRequests": 145,
  "failedRequests": 5,
  "cacheHits": 80,
  "cacheMisses": 70,
  "cacheHitRate": 53.33,
  "revocationChecks": 70,
  "revocationGood": 65,
  "revocationRevoked": 3,
  "revocationErrors": 1,
  "revocationUnsupported": 1,
  "revocationGoodRate": 92.86,
  "revocationRevokedRate": 4.29,
  "averageResponseTimeMs": 245,
  "uptimeSeconds": 3600,
  "startedAt": "2026-03-04T12:00:00.000Z",
  "requestsByStatus": {
    "200": 145,
    "502": 5
  },
  "requestsByError": {
    "certificate_fetch_error": 5
  }
}

Metrics Description

Metric	Description
`totalRequests`	Total number of requests
`successfulRequests`	Requests that returned 200 OK
`failedRequests`	Requests that returned errors
`cacheHits`	Requests served from cache
`cacheMisses`	Requests that required new certificate fetch
`cacheHitRate`	Percentage of requests served from cache
`revocationChecks`	Total revocation checks performed
`revocationGood`	Certificates with “good” revocation status
`revocationRevoked`	Certificates marked as revoked
`revocationErrors`	Revocation check errors
`revocationUnsupported`	Certificates without revocation info
`averageResponseTimeMs`	Average response time in milliseconds
`uptimeSeconds`	Time since API started
`requestsByStatus`	Requests grouped by HTTP status code
`requestsByError`	Failed requests grouped by error type