🌟 Feature-Flags & Experimentation Platform

A LaunchDarkly-style control plane and SDK — designed, built, and deployed from scratch.

This project demonstrates end-to-end backend engineering:
designing a multi-tenant control plane, building a Node.js SDK, wiring real-time flag delivery with SSE + S3 snapshots, and integrating with my other project Secure File Vault to prove instant, live feature rollouts.

Flip a flag → snapshot in S3 updates → SSE notifies SDKs → File Vault behavior changes in < 1 second.

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📌 Highlights

• Multi-tenant control plane (Node/Express + Postgres + Prisma)
  Tenants → projects → environments → flags/segments/rules → audit logs.
• Real-time delivery path
  Environment changes trigger:
  1️⃣ Snapshot build → versioned snapshot.json in S3
  2️⃣ SSE {version} event to clients
  3️⃣ SDKs re-fetch only when version bumps.
• Custom Node SDK
  • In-memory snapshot cache
  • Deterministic bucketing (murmur(userId + flagKey) % 100)
  • Segment evaluation (plan, country)
  • <1 s propagation from flip to client.
• Recruiter-facing Live Tour (React + Vite + Tailwind + shadcn/ui)
  • Flip Console (PATCH flags with admin JWT)
  • SSE Event Stream viewer
  • SLO badge (avg/p95 propagation)
  • SafeHouse client panel: watch API behavior change instantly.
• Secure File Vault Integration
  The SafeHouse API (secure file-vault project I built earlier) consumes the SDK to gate:
  • enable_encrypted_upload_v2
  • strict_rate_limit
  • enable_logs_page
  • max_upload_mb
  • download_link_ttl_hours

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🏗️ Architecture

flowchart LR
  A[Admin Dashboard / Live Tour] -->|PATCH flags| B(Control Plane API)
  B -->|write snapshot.json| S3[(S3 Bucket)]
  B -->|SSE /stream| SDK
  SDK -->|GET snapshot.json| S3
  SDK -->|evaluate flags| SH[SafeHouse API]

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