Browse categories
Explore
Fiverr Pro
English
$
USD
I will build a rest API backend with fastapi or spring boot
Emmanuel O
About this gig
Need a backend that actually holds up under load not just one that works in a demo?
I build REST API backends in FastAPI and Spring Boot, designed for reliability, concurrency, and clean architecture from the start.
My background includes a Spring Boot microservice handling 50+ concurrent users with thread-safe inventory logic and 85% JUnit test coverage resolving a race condition that caused data inconsistency under load. I build backends the same way I build everything else: from first principles, documented, and tested before delivery.
I build:
REST APIs with proper request validation, error handling, and status codes Database integration with MySQL, PostgreSQL, or Supabase Authentication and authorization (JWT, API keys) Concurrent request handling with thread-safety where it matters Docker configuration so your API deploys consistently anywhere Full documentation every endpoint, every parameter, every response
Every delivery includes clean source code, detailed inline comments, and a README your team can maintain without depending on me.
Message me before ordering if your requirements involve high concurrency, complex business logic, or integration with existing systems.
Get to know Emmanuel O
Emmanuel O
AI Automation and Backend Engineer, Python, Claude API, FastAPI
- FromCanada
- Member sinceOct 2024
- Avg. response time1 hour
Languages
English
I build production-ready AI automation systems and backend infrastructure that hold up under real conditions not just in demos.
Recent: a competition-winning game AI in C++ with parallel search and data structures, and an autonomous delivery rover with computer vision and real-time control, both on real hardware.
Stack: Python, FastAPI, Java, Spring Boot, C++, Docker, REST APIs. I specialise in Claude and OpenAI API integration, workflow automation, and reliable backend systems
Every delivery includes clean source code, documentation, and a README your team can maintain without depending on me
My Portfolio
Other Software Development Services I Offer
FAQ
FastAPI or Spring Boot — which should I choose?
FastAPI is faster to build with and ideal for Python-based systems, AI integrations, and lightweight APIs. Spring Boot suits enterprise Java environments, complex business logic, and high-concurrency systems. Message me with your stack and I'll recommend the right fit.
Can you integrate with my existing database or codebase?
Yes. Send me your schema or repo structure before ordering and I'll confirm compatibility and scope.
Do you write tests?
Yes — the Premium package includes test coverage. For Basic and Standard I write unit tests for critical logic. If you need full coverage on a smaller package, message me and we'll scope it.
Will my API handle multiple users at the same time?
Yes. Concurrency is something I design for explicitly — not an afterthought. My Spring Boot microservice project handled 50+ concurrent users with zero data inconsistency under load.
Can you deploy the API as well as build it?
Deployment instructions and Docker configuration are included in Standard and Premium. For full deployment to your cloud environment, message me before ordering so we can scope that correctly.
