API Development

Pro

Vasiliy Kuzmenko

Starting at

$

50

/hr

About this service

Summary

Develop robust, well-documented APIs using FastAPI, fully aligned with the OpenAPI 3.x specification. My solutions are designed for scalability and security, with optional integrations for databases (like PostgreSQL) and third-party services. What sets me apart is a focus on clean architecture, automated testing, and seamless frontend/backend collaboration through auto-generated API clients.

Process

Requirements Gathering – Define the API scope, endpoints, data models, and integration needs.
Design OpenAPI Specification – Create a structured and clear API design using the OpenAPI 3.x standard.
Set Up Project Structure – Initialize the FastAPI project with modular, scalable architecture.
Database Integration – Design and implement PostgreSQL models and migrations.
Develop Endpoints & Logic – Implement routes, business logic, and background tasks as needed.
Add Security & Middleware – Configure CORS, authentication, rate limiting, and logging.
Write Tests – Create unit and integration tests to ensure stability and correctness.
Documentation & Client Generation – Generate interactive API docs and client libraries if needed.
CI/CD & Deployment – Set up automated workflows and prepare the API for deployment.

FAQs

  • What technology do you use to build APIs?

    I use FastAPI, a modern and high-performance Python framework that follows OpenAPI 3.x standards, making it ideal for building scalable and well-documented APIs.

  • Will the API include documentation?

    Yes. Every API comes with auto-generated interactive documentation via Swagger UI and ReDoc, allowing developers to easily explore and test endpoints.

  • Can the API connect to a database?

    Absolutely. I integrate APIs with PostgreSQL, including full database modeling, schema migrations, and efficient query handling.

  • Can you add authentication or other security features?

    Yes. I implement modern security best practices such as OAuth2, API keys, CORS policies, and rate limiting based on your project needs.

  • Do you write tests for the API?

    Definitely. I include unit and integration tests to ensure that endpoints are reliable, secure, and easy to maintain over time.

  • How is the API delivered?

    The API is delivered as a Dockerized project, ready to deploy. Optionally, I can set up CI/CD pipelines for automatic testing and deployment.

  • Can the API work with external services?

    Yes. I can build integrations with third-party APIs, authentication providers, payment gateways, or any other external services your application requires.

What's included

  • FastAPI-Based API

    A fully functional API built with FastAPI, following OpenAPI 3.x specification for clear structure, validation, and automatic documentation.

  • Modular & Secure Architecture

    API designed to integrate with internal and third-party services (e.g. authentication, logging, payments), with security best practices in place (rate limiting, input validation, CORS, etc.).

  • OpenAPI Documentation

    Auto-generated, interactive Swagger UI and ReDoc documentation for easy testing and integration by frontend developers or third-party consumers.

  • Testing Suite

    Unit and integration tests covering key API endpoints and logic to ensure reliability and stability.

  • Deployment-Ready Build

    Dockerized setup or environment configuration included, ready for deployment to staging/production environments.

  • PostgreSQL Integration (Optional)

    Database models and schema can be integrated with PostgreSQL, including support for migrations and data consistency.

  • CI/CD Integration (Optional)

    Automated workflows for testing, linting, and deploying the API using GitHub Actions, GitLab CI.

Skills and tools

Backend Engineer

Software Architect

Fullstack Engineer

FastAPI

FastAPI

Postman

Postman

Python

Python

Industries

Engineering & Architecture
Computer Software
IT Infrastructure

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