Overview

Datadog Feature Flags for server-side applications allow you to remotely control feature availability, run experiments, and roll out new functionality with confidence. Server-side SDKs integrate with the Datadog APM tracer and use Remote Configuration to receive flag updates in real time.

This guide covers the common setup required for all server-side SDKs, including Agent configuration and application environment variables. Select your language or framework to view SDK-specific setup instructions:

Prerequisites

Before setting up server-side feature flags, ensure you have:

• Datadog Agent 7.55 or later installed and running
• Datadog API key configured
• APM tracing enabled in your application

Agent configuration

Server-side feature flags use Remote Configuration to deliver flag configurations to your application. Enable Remote Configuration in your Datadog Agent by setting DD_REMOTE_CONFIGURATION_ENABLED=true or adding remote_configuration.enabled: true to your datadog.yaml.

See the Remote Configuration documentation for detailed setup instructions across different deployment environments.

Polling interval

The Agent polls Datadog for configuration updates at a configurable interval. This interval determines the average time between making a flag change in the UI and the change becoming available to your application.

# Optional: Configure polling interval (default: 60s)
DD_REMOTE_CONFIGURATION_REFRESH_INTERVAL=10s

Application configuration

Configure your application with the standard Datadog environment variables. These are common across all server-side SDKs:

# Required: Service identification
DD_SERVICE=<YOUR_SERVICE_NAME>
DD_ENV=<YOUR_ENVIRONMENT>
DD_VERSION=<YOUR_APP_VERSION>

# Agent connection (if not using default localhost:8126)
DD_AGENT_HOST=localhost
DD_TRACE_AGENT_PORT=8126

# Enable Remote Configuration in the tracer
DD_REMOTE_CONFIG_ENABLED=true

Context attribute requirements

Use flat attributes in your evaluation context:

const evaluationContext = {
  targetingKey: req.session?.userID,
  companyId: req.session?.companyID,
  tier: 'enterprise'
};

const value = client.getBooleanValue('my-flag', false, evaluationContext);

Avoid nested objects and arrays:

// These attributes will cause exposure events to be dropped
const evaluationContext = {
  targetingKey: req.session?.userID,
  company: { id: req.session?.companyID },  // nested object - NOT SUPPORTED
  roles: ['admin', 'user']                   // array - NOT SUPPORTED
};

Further reading

Additional helpful documentation, links, and articles:

Client-Side Feature FlagsDOCUMENTATION Remote ConfigurationDOCUMENTATION