Feature Flags

Drop Feature Flags

Sources: src/drop-app/src/lib/feature-flags.ts, src/drop-app/src/lib/features.ts

Feature Flag System

Source: feature-flags.ts

Architecture

Feature flags are controlled via environment variables with the pattern:

NEXT_PUBLIC_FF_<SCREAMING_SNAKE_CASE>=true|false

The NEXT_PUBLIC_ prefix ensures flags are available on both server and client (inlined at build time by Next.js).

Conversion example: physicalCards → NEXT_PUBLIC_FF_PHYSICAL_CARDS

Source: feature-flags.ts:42-45

Available Flags

Source: feature-flags.ts:27-36

Server-Side API

featureGate usage in routes:

// In any route handler:
const gate = featureGate("physicalCards");
if (gate) return gate;  // Returns 404 with "Feature not available"

Source: feature-flags.ts:80-88

Routes using featureGate:

Client-Side API

These work because NEXT_PUBLIC_* env vars are inlined at build time — no server roundtrip needed.

Source: feature-flags.ts:94-114

Feature Tracking System

Source: features.ts

A separate system for tracking implementation progress of Drop features. Not runtime flags — this is a development tracking tool.

Feature Interface

interface Feature {
  id: string;              // e.g., "auth-001"
  category: string;        // e.g., "Authentication"
  name: string;            // e.g., "User Registration"
  description: string;
  status: "pending" | "in_progress" | "passing" | "failing";
  priority: number;        // 1 = highest
  dependencies: string[];  // IDs of prerequisite features
  acceptanceCriteria: string[];
  implementedAt?: string;  // ISO date
  testedAt?: string;       // ISO date
}

Feature Categories and Status

All Features

Helper Functions

Source: features.ts:284-357

Environment Variable Summary