Backend API & Systems Engineering
I design and implement application backends that treat data integrity, permissions and recovery as product requirements—not afterthoughts.
What does this work deliver?
A maintainable backend with explicit authorization, reliable state transitions, clear integration contracts and documentation.
See the implementation in Fitter Health — production platform.
What problems does this solve?
A feature can seem simple in a UI yet require consistent state across accounts, databases and external systems. When an API times out, a worker retries, or a user loses permission, the system still needs a predictable answer. I start by mapping these cases rather than choosing a framework first.
Good fit for
- Teams building a new API-backed product
- Organizations maintaining Django or Node.js services
- Product engineers connecting user workflows to external providers
1. Discover the business transaction
I map the user action, validation, actors and state changes before writing endpoints. For bookings, memberships and notifications, the critical question is what must be true before the user sees success. I document who can access each record and which operations must remain atomic.
Engineering checks
- Define domain records and ownership
- Write API contracts and errors
- List duplicate and partial-failure scenarios
2. Choose data and application boundaries
PostgreSQL constraints and transactions usually handle the central business facts. Django/DRF or Node.js can expose the contract. I introduce asynchronous processing only where work needs retries or should not delay the request. This avoids speculative complexity around otherwise straightforward business operations.
Engineering checks
- Use server-side authorization and validation
- Set transaction and idempotency boundaries
- Separate durable work from user-facing latency
3. Test, deploy and make failure visible
Integration tests cover permissions, expired sessions and database rules. Operational monitoring should report worker failures and delayed jobs, not just HTTP health. Deployment planning includes migrations, secrets, rollback and a clear way for another engineer to diagnose a problem.
Engineering checks
- Test failure paths and duplicate delivery
- Instrument errors and job status
- Prepare a deploy and rollback checklist
Expected result and engineering trade-off
A maintainable backend with explicit authorization, reliable state transitions, clear integration contracts and documentation.
A modular application with sound data rules is usually more useful than multiple services created for their own sake.
Have a backend, data, or product challenge?
Review all service areas, see published work, or contact me about a role or project.
Let’s talk
I like working through complex problems with people who care about the details. Have a product to build, an engineering role, or an interesting challenge? Let’s start a conversation.
SaaimOpen to full-time roles, contract work, and conversations about things worth building.