JOB TITLE
Senior Python / FastAPI Backend Developer for AI B2B MVP
CATEGORY
Programming & Development
TOP SKILLS TO SELECT ON GURU
Python
FastAPI
PostgreSQL
SQLAlchemy
Docker
REST API
Git
Artificial Intelligence
Data Engineering
pgvector
PAYMENT TERM
Fixed Price / Milestone-Based
WORK ARRANGEMENT
Freelance contract with full-time availability required during the agreed project period, approximately 40 hours per week, Monday to Friday.
JOB DESCRIPTION
We are looking for a strong backend-oriented developer to build the technical foundation of an AI-enabled B2B MVP.
This is a freelance contract requiring full-time project availability, approximately 40 hours per week, Monday to Friday. The project should be the developer's primary active development commitment during the agreed project period. Small concurrent commitments are acceptable only if they do not affect daily availability, communication or milestone delivery.
The detailed product specification will be shared only with the selected developer.
Main responsibilities:
- Design and maintain the core backend architecture
- Build REST APIs using Python / FastAPI
- Design PostgreSQL database models and migrations
- Integrate several external APIs and data providers
- Normalize and deduplicate structured data
- Implement reusable provider and service abstractions
- Implement PostgreSQL + pgvector based retrieval
- Build reliable data ingestion pipelines
- Implement structured logging and error handling
- Write unit and integration tests
- Maintain Docker / Docker Compose configuration
- Support deployment to a standard Linux server
- Review shared architecture changes and keep the codebase consistent
- Coordinate technically with a second developer working on separate modules
Preferred technical experience:
- Python
- FastAPI
- PostgreSQL
- SQLAlchemy
- Alembic
- pgvector
- Docker / Docker Compose
- Git / GitHub
- REST APIs
- Async Python where appropriate
- LLM APIs
- Embeddings
- Semantic search
- Ranking / reranking
- Data pipelines
- Structured outputs
- Background jobs
- Large datasets
- S3-compatible object storage
Architecture requirements:
- PostgreSQL must be the primary system of record.
- pgvector should be used for vector embeddings during the MVP unless measured scale testing demonstrates a real need for a separate vector database.
- Large files and datasets must be stored outside PostgreSQL through a replaceable StorageService abstraction.
- Redis, if used, must only be used for temporary cache / queue infrastructure and not as permanent storage.
- External AI and embedding providers must be accessed through replaceable adapters.
- The application must remain portable and deployable on a standard Linux server using Docker.
- Core functionality must not depend on proprietary hosting-specific services.
Development process:
- The project is divided into fixed milestones with clear acceptance criteria.
- All work must be committed continuously to a private GitHub repository owned by the Client.
- Work must be performed through feature branches and Pull Requests.
- Each milestone must include working source code, automated tests, required migrations, Docker configuration, documentation, sample outputs where applicable, known issues and reproducible setup instructions.
- A visual demonstration alone does not constitute completion.
- The next milestone starts only after the current milestone has been accepted unless otherwise agreed by the Client.
AI coding tools:
Use of Codex, Claude Code, Cursor, GitHub Copilot or similar tools is welcome. The developer remains responsible for architecture, correctness, testing, security, maintainability and code quality. Unreviewed or low-quality AI-generated code will not be accepted.
Code quality:
Please avoid duplicate implementations, unused dependencies, placeholder code presented as finished work, large unstructured files, hard-coded secrets, silent exception handling, unnecessary infrastructure and vendor lock-in.
Intellectual property and confidentiality:
All project-specific source code, implementation, documentation and proprietary logic created under the project will belong to the Client. The project and repository must remain private. Do not publish source code, screenshots, architecture, product details, project descriptions or case studies without written permission. Any third-party or open-source dependency must be disclosed together with its license.
Ideal candidate:
- Strong backend and data architecture skills
- Writes clean and testable code
- Comfortable working from detailed technical specifications
- Understands data-heavy backend systems
- Can explain technical decisions clearly
- Comfortable with code review
- Can coordinate effectively with another developer in the same repository
- Uses AI coding tools productively without sacrificing quality
- Can provide full-time availability for this freelance contract during the agreed project period
Please include in your Quote:
1. Relevant backend / AI development experience
2. Examples of Python / FastAPI / PostgreSQL projects
3. Experience with external API integrations
4. Experience with embeddings / semantic search, if applicable
5. Experience working with another developer through Pull Requests
6. Your current timezone and normal working hours
7. Your weekly availability
8. Your earliest possible start date
9. Whether you currently have another full-time project commitment
10. Whether you are comfortable working milestone-by-milestone in a Client-owned private GitHub repository
Please do not send a generic agency proposal. We prefer direct communication with the developer who will personally perform the work.
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