Feature flags are a powerful way to control your application's behavior without needing to redeploy. Recently, I needed to implement a clean, backend-driven feature flag system to enable or disable features globally or per account. Here's how we did it using just Next.js API routes, Prisma, and a simple frontend fetch approach. No extra libraries or state management layers involved.

🌐 The Goal

We wanted to:

• Define feature flags that are either global or account-specific
• Let the backend serve the flags
• Have a simple way to access those flags on the client

📄 Database Schema (Prisma)

model FeatureFlag {
  id        String   @id @default(uuid())
  flagKey   String
  value     Boolean
  scope     FlagScope
  accountId String?
  updatedAt DateTime @updatedAt
}

enum FlagScope {
  global
  account
}

This allows each flag to be:

• Global: applies to everyone
• Account-level: overrides global for a specific account

🚀 API Endpoint to Fetch Flags

We expose an endpoint at /api/featureFlags. It optionally accepts an accountId.

If you pass the account ID, it fetches both global and account-specific flags.

GET /api/featureFlags?accountId=abc123

Example Response

{
  "success": true,
  "flags": {
    "global": {
      "newDashboard": false
    },
    "account": {
      "abc123": {
        "newDashboard": true
      }
    }
  }
}

💪 Using Flags on the Frontend

Just make a fetch call during getServerSideProps or useEffect:

const res = await fetch(`/api/featureFlags?accountId=${accountId}`);
const { flags } = await res.json();

const isNewDashboardEnabled =
  flags.account?.[accountId]?.newDashboard ??
  flags.global?.newDashboard ??
  false;

No Redux, no state libraries — just native fetch.

➕ Adding a New Flag

1. Add a global default:

INSERT INTO "FeatureFlag" (
  id, flagKey, value, scope, accountId, updatedAt
) VALUES (
  gen_random_uuid(), 'someFeature', false, 'global', NULL, CURRENT_TIMESTAMP
);

2. Optionally override for an account:

INSERT INTO "FeatureFlag" (
  id, flagKey, value, scope, accountId, updatedAt
) VALUES (
  gen_random_uuid(), 'someFeature', true, 'account', 'abc123', CURRENT_TIMESTAMP
);

✨ Final Thoughts

You don’t always need a fancy flag service or state management solution. If you're working with a small team or MVP, this setup can take you very far.

It’s easy to build, debug, and extend — and more importantly, keeps your logic flexible across environments and users.

Let me know if you’re implementing something similar or want to share ideas on improving this further!