What we build on the server
APIs your app and partners can rely on
REST APIs in Node.js and TypeScript with input validation and authentication, written so another developer can pick them up.
Data models that hold up as you grow
Firestore data models designed around how the app reads data, with the indexes and backfills to change them safely later.
Background jobs and scheduled work
Queues, retries and scheduled tasks for emails, reminders, imports, exports and reports, so slow work never blocks a user.
Security rules and access control
Per-user and per-team access enforced on the server and tested in the emulator, so one customer can never read another customer’s data.
Cloud cost under control
Right-sized functions and instances, fewer wasted reads, and budget alerts set up in Google Cloud.
Fixes for backends that already exist
Slow endpoints, failing functions, duplicated records and broken deploys, diagnosed from the logs and fixed with a test that proves it.
What we run in production
App369 built and runs the backend for Workspace369, a client-work platform for freelancers and small agencies. It is the same work we do for clients.
More than 20 TypeScript Cloud Functions codebases
Billing, payments, messaging, AI, search, PDF, e-signature, scheduling and more, each deployed on its own.
Firestore security rules with automated tests
Workspace and member-level access, covered by emulator tests.
Queues, secrets and signing
Cloud Tasks for background work, Secret Manager for API keys, and Cloud KMS-backed signatures on PDF documents.
An MCP server for AI assistants
OAuth-protected access to workspace data for Claude and ChatGPT, scoped per user.
Stack: Node.js, TypeScript, Firebase, Firestore, Cloud Functions, Cloud Tasks, Secret Manager, Typesense
Prefer a fixed price?
Fixed scope, fixed price, paid upfront. The work happens in writing; no call needed.
- Firebase Security Rules Audit + Fix PRTests whether one user can read or edit another customer’s data, and fixes what it finds.$950
- Firebase Cost-Cut AuditWhere your Firebase or Google Cloud bill goes, with savings ranked by dollars a month and risk.$750
- MCP Connector for your SaaSAn MCP server over your existing REST API, so your product works inside Claude and ChatGPT.$2,500
Frequently Asked Questions
Which backend technologies does App369 use?
Mostly Node.js and TypeScript on Firebase and Google Cloud: Cloud Functions, Cloud Run, Firestore, Cloud Tasks and Secret Manager. We pick the stack that fits your product and team, and keep what you already run where it makes sense.
Can you work on a backend someone else built?
Yes. Most backend work starts with an existing codebase. We read it, reproduce the problem, fix it with a test, and write down what we changed so your team can follow it.
Do you build the app and the backend together?
Yes. One developer handles the mobile or web app and the server side, so the API is designed around the screens that use it.
How is backend work priced?
Small, well-defined jobs such as a security rules audit or a cost audit have fixed prices on our fixed-price page. Larger builds get a written fixed quote after we have scoped them.
Get a Personalized Assessment by Email
Submit your project details and we'll reply by email with a personalized assessment, usually within one business day.
Prefer a call? Consultations are $100 per 15 minutes, paid upfront.