FeatureSignals

Relay Proxy

The relay proxy is a lightweight Go binary that caches flag values from the central FeatureSignals API and serves them locally.

Use Cases

  • Edge deployment: Run the proxy close to your application for sub-millisecond flag reads
  • On-premises: Serve flags within your private network
  • High availability: Cached flags survive brief upstream outages
  • Reduce API load: Hundreds of SDK instances connect to the proxy instead of the central API

Running the Relay Proxy

bash
docker run -d \
  -p 8090:8090 \
  -e FS_API_KEY="fs_srv_your_key" \
  -e FS_ENV_KEY="production" \
  -e FS_UPSTREAM="http://your-server:8080" \
  featuresignals-relay

Configuration

Flag / Env VarDefaultDescription
-api-key / FS_API_KEY(required)Server API key
-env-key / FS_ENV_KEY(required)Environment key
-upstream / FS_UPSTREAMhttps://api.featuresignals.comUpstream API URL
-port / FS_PORT8090Local listening port

Connecting SDKs

typescript
const client = new FeatureSignalsClient('fs_srv_...', {
  envKey: 'production',
  baseURL: 'http://relay-proxy:8090', // ← proxy URL
});

Next Steps