Feature Flag & Progressive Rollout Expert

English | Bahasa Indonesia

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English

Purpose & Overview

Production-grade guidelines for feature flag management, progressive feature rollouts, canary deployments, A/B testing experiment analysis, and dynamic server-side/client-side feature evaluation using PostHog, LaunchDarkly, and GrowthBook.

Key Capabilities

• Feature Gating: Decoupling code deployment from feature release with instant kill-switches.
• Canary & Percentage Rollout: Incrementally releasing new features to 5%, 25%, 50%, and 100% of user segments.
• Experimentation Engine: Statistical A/B testing with conversion metrics and variant analytics.

import { PostHog } from 'posthog-node';

const posthog = new PostHog(process.env.POSTHOG_API_KEY!);

export async function isNewCheckoutEnabled(userId: string) {
  const isEnabled = await posthog.isFeatureEnabled('new-checkout-flow', userId);
  return isEnabled;
}

Implementation Checklist

• Initialize the Feature Flag client (e.g., PostHog/LaunchDarkly) securely on the server and client.
• Create flags in the dashboard before referencing them in code.
• Set fallback (default) values for flags in case of network failures.
• Use user identification (User ID/Distinct ID) consistently to ensure the same user gets the same flag variant.
• Clean up obsolete flags from the codebase once a feature is 100% rolled out.

Orchestration & Integration

• Integrates with: data-telemetry-expert, e2e-testing-expert, ci-cd-devops-architect.

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Bahasa Indonesia

Deskripsi

Panduan tingkat produksi untuk manajemen feature flags, rilis fitur bertahap (progressive rollout), canary deployment, pengujian A/B testing, dan evaluasi fitur dinamis menggunakan PostHog, LaunchDarkly, dan GrowthBook.

Fitur Utama

• Feature Gating: Memisahkan deployment kode dari rilis fitur dengan tombol kill-switch instan.
• Rilis Bertahap (Canary): Meluncurkan fitur baru secara bertahap ke 5%, 25%, 50%, hingga 100% segmen pengguna.
• Mesin Eksperimen: Pengujian A/B statistik dengan metrik konversi dan analitik varian.

Checklist Implementasi

• Inisialisasi klien Feature Flag (misal: PostHog/LaunchDarkly) secara aman di server dan klien.
• Buat flag di dasbor sebelum mereferensikannya dalam kode.
• Tetapkan nilai fallback (default) untuk flag sebagai antisipasi kegagalan jaringan.
• Gunakan identifikasi pengguna (User ID/Distinct ID) secara konsisten untuk memastikan pengguna yang sama mendapat varian flag yang sama.
• Bersihkan flag yang kedaluwarsa dari basis kode setelah fitur 100% dirilis.

Integrasi Orkestrasi

• Terintegrasi dengan: data-telemetry-expert, e2e-testing-expert, ci-cd-devops-architect.