🚀 Feature Flag Backend

A backend feature flag platform supporting environment isolation, rule-based targeting, and percentage-based rollout — designed to power SDKs and dynamic feature control without redeployments.

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✨ What this does

This service allows teams to:

• Create feature flags per environment (DEV / STAGING / PROD)
• Enable or disable features instantly
• Gradually roll out features using percentage-based rollout
• Target features using rule-based conditions
• Evaluate features dynamically at runtime

All decision logic lives on the backend.

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🧠 How feature evaluation works

Feature evaluation follows this order:

Global Toggle → Percentage Rollout → Rules → Final Decision

If any step fails, the feature is disabled for that request.

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🔌 Evaluation API

POST /api/features/{key}/evaluate?env=STAGING

Request

{
  "attributes": {
    "userId": "user-123",
    "country": "IND"
  }
}

Response

true | false

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✅ Key Features

• Environment-scoped feature flags
• Rule-based targeting (e.g. country, user attributes)
• Deterministic percentage-based rollout
• Centralized evaluation engine
• Safe runtime evaluation (no redeploys)

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🧩 Why SDKs?

While this backend provides full evaluation logic, direct API usage is not developer-friendly at scale.

SDKs (built separately) will:

• Provide a simple isEnabled() API
• Hide HTTP and error handling
• Cache results safely
• Ensure consistent behavior across services

Backend is the brain. SDKs are thin clients.

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🛣️ Roadmap

• Rollout percentage update API
• Java SDK (followed by other languages)
• Caching & observability
• Admin UI

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📦 Scope

This repository contains backend logic only. SDKs and client libraries live in separate repositories.

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📄 License

(To be added)