Python Backend Developer (FastAPI) — AI Fitness Coach platform | Consultation + assistance
Description
I am looking for an experienced Python developer for consulting and assistance with the backend of the mobile application AI Fitness Coach.
What is already available:
- Ready frontend on React Native
- Backend is ~80-85% ready (microservices architecture)
- 4 microservices: Auth, Fitness, WebSocket Chat, AI Coach
- ~12,800 lines of Python code
- Docker Compose configuration for the entire stack
Stack:
- Python 3.13, FastAPI, SQLModel (Pydantic + SQLAlchemy)
- PostgreSQL 15, Redis 7
- LangChain / LangGraph (AI part)
- Celery (asynchronous tasks)
- Docker, Alembic (migrations)
- WebSocket (real-time chat with AI coach)
What is required from you:
- Code review of the existing backend — assessing the architecture, identifying issues
- Refinement of AI Coach Service — HTTP API wrapper over LangChain
- Consultations on best practices (security, performance, deployment)
- If necessary — assistance with database migrations, email notifications, tests
Work format:
- Part-time / consulting
- Communication via Telegram
- Code on GitHub (private repository)
- Possible further collaboration on a permanent basis
Candidate requirements:
- Experience with FastAPI for at least 1 year
- Understanding of microservices architecture
- Experience working with PostgreSQL, Redis, Docker
Budget:
Hourly payment, to be discussed individually.
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1 day16 USD
1 day16 USD
Good day!
I am interested in your project AI Fitness Coach and the task of refining the backend on FastAPI. My 5 years of experience in Python development includes deep expertise with FastAPI and building microservice architectures, which perfectly matches your stack and the current state of the project. I also have experience in integrating AI services and developing WebSocket chats, which will be very useful for your AI Coach and WebSocket Chat modules. I am ready to provide consulting support and help finalize the remaining 15-20% of the backend to readiness.
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1 day23 USD
656 9 0 1 day23 USD
Good day, Sergey!
In general, the task is clear, but for an accurate response regarding deadlines and price, I would like to clarify some questions that arose after analyzing your task.
Please write in private messages – we will discuss the details and your wishes.
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21 days451 USD
2162 22 2 21 days451 USD
Hello, you chose a good stack.
- I would start with tests to ensure that further changes won't break anything.
- I can conduct a code review, starting with things that might be slow right now, or there might be payment methods.
- Also, a review of the architecture if needed, but that will definitely be after the tests.
- I can also help with deployment, setting up CI/CD.
I can just do reviews/consulting (text, meetings), or dive deeper into the code.
My rate is 20 USD/hour.
… Write to me, and we will discuss the details.
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2 days29 USD
253 1 1 2 days29 USD
Hello! I can complete this task, efficiently and quickly, as I have experience and am ready for new challenges.
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1 day23 USD
1595 7 0 1 day23 USD
I am among the top 5 developers in the category of "Artificial Intelligence and Machine Learning" among ~2100 specialists on the platform.
I guarantee:
- Fast and quality execution of the task
- Strict adherence to deadlines
- Regular communication throughout the entire process
I would be happy to discuss the details of your project in private messages.
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3 days45 USD
738 9 1 3 days45 USD
Hello! Your project has sparked great interest in me. I am ready to start working immediately and ensure high-quality execution.
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1 day23 USD
1910 14 0 1 day23 USD
Hello. I have been developing Backend solutions in Python for 4 years. During this time, I have worked on projects of varying complexity - from the simplest to full-fledged platforms (an AI platform consisting of several microservices that work together) for automating business processes. I would be happy to help you with your task. I have repeatedly had experience working with someone else's code, and I will gladly consult and identify the strengths and weaknesses of your software. I have a confident understanding of all the listed technologies. I would like to discuss the details of our collaboration in private messages.
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1 day18 USD
62 1 day18 USD
Ready to conduct a code review and refine the AI Coach Service for the Fitness Coach platform. I will use FastAPI, LangChain/LangGraph — I will create an HTTP API wrapper and check the security. I will start immediately after selection, consultation in Telegram.
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1 day23 USD
426 10 0 1 day23 USD
Hello!
I have over 3 years of commercial experience with Python/FastAPI and have worked many times with similar microservice architecture: separate services (Auth, Core, AI, Realtime), Redis as a cache and broker, Celery for background tasks, Docker Compose for local orchestration. I have a good understanding of service-to-service communication, isolation of domain logic, and scaling under load.
What I can bring to your project:
* In-depth code review focusing on clean architecture, dependency injection, correct operation of the async event loop, avoiding blocking operations, transactionality, and consistency.
* Security checks: JWT flow (access/refresh), rate limiting, protection of WebSocket connections, validation of incoming data, handling of secrets.
* Refinement of the AI Coach Service: building a stable HTTP wrapper over LangChain/LangGraph, managing state control, handling retries and fallbacks, optimizing latency, preparing for horizontal scaling.
… * Performance analysis (N+1 queries, indexes, connection pooling, caching in Redis).
* Recommendations on CI/CD, logging, observability (structured logs, basic tracing), correct migration strategy through Alembic.
I usually work like this: technical audit → structured list of risks and technical debt → improvement plan → implementation.
I am ready to engage in a part-time/consultation format and help bring the backend to a stable production-ready state.
I look forward to collaborating!
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1 day23 USD
93540 1262 1 10 1 day23 USD
Hello. I work with FastAPI. I am ready to collaborate. Please contact me. I will be happy to collaborate.
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7 days23 USD
3714 17 0 7 days23 USD
Hello! 🤖💪
I have experience working with FastAPI, microservices architecture, and AI modules (LangChain/LangGraph). I am ready to conduct a thorough code review (architecture, dependencies, service boundaries), refine the AI Coach Service (a clear HTTP wrapper over LangChain, state/context management), assist with migrations (Alembic), email notifications, tests, and stabilization of the WebSocket part.
Proposed stack: Python 3.13, FastAPI, SQLModel (Pydantic+SQLAlchemy), PostgreSQL 15, Redis 7, Celery, Docker, Alembic, WebSocket, LangChain/LangGraph.
I am ready to discuss project details in private, with the possibility of long-term collaboration.
Best regards, Andriy!
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1 day23 USD
15886 378 0 1 1 day23 USD
Good day.
I have experience working with a similar stack and several similar completed projects.
We can discuss the details of the work format.
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30 days338 USD
698 21 0 30 days338 USD
Hello. I can do your project. I have experience. Write to me, we will agree.
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