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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

Flag Name Env Var Default Description
virtualCards NEXT_PUBLIC_FF_VIRTUAL_CARDS false Virtual card issuance
physicalCards NEXT_PUBLIC_FF_PHYSICAL_CARDS false Physical card ordering
cardDetails NEXT_PUBLIC_FF_CARD_DETAILS false View full card details
cardFreeze NEXT_PUBLIC_FF_CARD_FREEZE false Card freeze/unfreeze
cardPin NEXT_PUBLIC_FF_CARD_PIN false Card PIN management
spendingLimits NEXT_PUBLIC_FF_SPENDING_LIMITS false Card spending limits
notifications NEXT_PUBLIC_FF_NOTIFICATIONS true Push notifications
merchantDashboard NEXT_PUBLIC_FF_MERCHANT_DASHBOARD true Merchant dashboard

Source: feature-flags.ts:27-36

Server-Side API

Function Return Type Description
isEnabled(flag) boolean Check if a flag is enabled
getAllFlags() FeatureFlags Get all flags with current values
featureGate(flag) NextResponse | null API middleware: returns 404 response if disabled, null if enabled

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:

Route Flag
POST /api/cards/[id]/physical physicalCards
POST /api/cards/[id]/pin cardPin
GET /api/cards/[id]/limits spendingLimits
PUT /api/cards/[id]/limits spendingLimits
GET /api/notifications notifications
PATCH /api/notifications notifications

Client-Side API

Function Return Type Description
useFeatureFlag(flag) boolean React hook for a single flag
useFeatureFlags() FeatureFlags React hook for all flags

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

Category Total Passing Pending Notes
Authentication 4 3 1 (Biometric Login)
KYC 1 1 0
Banking 6 5 1 bank-006 (Top-up via Card) is FUTURE — incompatible with pass-through model
Cards 4 4 0 FUTURE — all card features are gated behind feature flags (default: false)
Notifications 1 0 1 (Push Notifications)

All Features

ID Name Status Priority Dependencies Notes
auth-001 User Registration passing 1 -
auth-002 PIN Login passing 1 auth-001
auth-003 Logout passing 2 auth-002
auth-004 Biometric Login pending 3 auth-002
kyc-001 Identity Verification passing 1 auth-001
bank-001 IBAN Generation passing 1 kyc-001
bank-002 Balance Display passing 1 bank-001 AISP read-only
bank-003 Send Money passing 1 bank-002 PISP from user's bank
bank-004 Receive Money passing 1 bank-001
bank-005 Transaction History passing 2 bank-003, bank-004
bank-006 Top-up via Card passing 2 bank-001 FUTURE — no wallet in pass-through model
card-001 Virtual Card Issuance passing 1 kyc-001 FUTURE — feature-flagged
card-002 Card Freeze/Unfreeze passing 2 card-001 FUTURE — feature-flagged
card-003 Card Transactions passing 1 card-001 FUTURE — feature-flagged
card-004 Physical Card Order passing 3 card-001 FUTURE — feature-flagged
notif-001 Push Notifications pending 3 auth-001

Helper Functions

Function Description
getFeaturesByStatus(status) Filter features by status
getFeaturesByCategory(category) Filter features by category
getFeatureStats() Get counts: total, passing, pending, inProgress, failing, percentComplete
getReadyFeatures() Features whose dependencies are all passing
printFeatureReport() Formatted text report

Source: features.ts:284-357

Environment Variable Summary

Variable Purpose Default
NEXT_PUBLIC_FF_VIRTUAL_CARDS Enable virtual cards false
NEXT_PUBLIC_FF_PHYSICAL_CARDS Enable physical cards false
NEXT_PUBLIC_FF_CARD_DETAILS Enable card detail view false
NEXT_PUBLIC_FF_CARD_FREEZE Enable card freeze false
NEXT_PUBLIC_FF_CARD_PIN Enable card PIN false
NEXT_PUBLIC_FF_SPENDING_LIMITS Enable spending limits false
NEXT_PUBLIC_FF_NOTIFICATIONS Enable notifications true
NEXT_PUBLIC_FF_MERCHANT_DASHBOARD Enable merchant dashboard true
NEXT_PUBLIC_SERVICE_MODE mock or production mock
DATABASE_URL PostgreSQL 16 connection string -Required (usesno SQLite)SQLite fallback)
JWT_SECRET JWT signing secret dev-only fallback
NEXT_PUBLIC_APP_URL App URL for CSRF -
SEED_DEMO Enable demo data in staging -
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