Stop starting every project from an empty folder. The Developer Integration Toolkit is six production-ready Node.js modules that solve the same problems every backend needs: login, clean API responses, webhooks, Google Sheets logging, Telegram alerts and proper error handling. Drop a module into your project, follow its README, and move on to the feature your client is actually paying for.

What's inside: 01 — Auth System: Firebase Authentication with the Admin SDK — Bearer token verification, role handling (admin / user), protected Express routes, and a browser sign-in example. The server never sees a password. 02 — API Templates: a standard response format, request validation, pagination helpers, rate limiting, and a complete example CRUD API with a working server. 03 — Webhooks: signature verification (HMAC), an event dispatcher, a retry queue with backoff, and a receiver endpoint — so you never lose a webhook or process a fake one. 04 — Google Sheets: log form submissions and events straight to a Google Sheet with the Sheets API, with a service-account setup guide. 05 — Telegram Notifications: send yourself alerts and order notifications on Telegram with a bot, plus working examples. 06 — Error Handling & Logging: a typed AppError class, structured logging, Express error middleware and an async handler wrapper, so errors stop crashing your server and start telling you what happened. Demo Order App: a small working Express app that uses the modules together. Every module has its own README. 66 automated tests, all passing — run npm test yourself after download: 7 test suites, 66 tests, 0 failures.

Who it's for: Freelance Node.js developers who rebuild auth and webhooks for every client. Indie hackers shipping a side project and tired of copy-pasting from old repos. Junior developers who want to see how production code is actually structured — with tests, not just tutorials.

What you need: Node.js 18+ and npm — that's all you need to run the code and the tests. A free Firebase project — only for the auth module. A Telegram bot token — only for the notifications module (free via BotFather). A Google service account — only for the Sheets module (free). Each module is independent: use one, use all six, use none of the ones you don't need.

What you get: 52 files in one ZIP (992 KB): 6 module folders with code, tests and READMEs, the demo order app, package.json, package-lock.json and a .env.example. Commercial use allowed: use the code in your own projects and in work you sell to clients. You may not resell or redistribute the toolkit itself as a product.

FAQ: Do the tests really pass? Yes — 66 tests, 0 failures, verified on the exact files in this download. Run npm test yourself after you download it; the output is shown in the preview images. Do I need Firebase for the whole toolkit? No. Only the auth module uses Firebase. Can I use this code in client projects? Yes. Commercial use is allowed — use it in your own projects and in work you sell to clients. The only restriction is that you can't resell or redistribute the toolkit itself.