I will do api development rest api integration with node js express js for backend


About this gig
Need a reliable API development, REST API integration, or Node.js backend for your web or mobile application? I build secure, scalable, and high-performance REST APIs with Node.js and Express.js designed around your business needs.
I can develop your backend from scratch, improve an existing API, connect third-party services, or create database-driven API endpoints that communicate smoothly with your frontend, mobile app, or external platforms.
What I offer:
- REST API & custom API development
- Node.js & Express.js backend development
- API integration & third-party API integration
- Database integration with MongoDB, PostgreSQL & MySQL
- JWT authentication & OAuth 2.0
- Secure API endpoints and backend security
- User authentication and authorization
- JSON/API data handling
- Payment, SaaS, CRM and external service integrations
- Backend optimization, debugging and deployment
My technology stack: Node.js, Express.js, JavaScript, MongoDB, PostgreSQL, MySQL, JWT, OAuth 2.0, AWS and DigitalOcean.
You'll receive clean, structured and maintainable code, commented source code, reliable API functionality and a backend built with scalability in mind.
Get Started Now!
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Get to know David
AI App ' Full Stack Developer ' Flutter, Web Apps, APIs ' SaaS
- FromGermany
- Member sinceSep 2026
- Avg. response time1 hour
Languages
English, German, Arabic, Spanish, French, Italian, Luxembourgish
FAQ
Can you build an API for my existing website or mobile app?
Yes. I can develop and integrate REST APIs with your existing web or mobile application. I can also review your current backend, identify issues, and extend or improve the existing API without rebuilding everything from scratch.
Can you connect my API to a database?
I can connect your backend API to MongoDB, PostgreSQL, or MySQL and create the required database operations, including creating, reading, updating, and deleting application data.
Can you integrate payment gateways or external services?
Yes. I can integrate third-party APIs and external services such as payment gateways, email platforms, CRM systems, authentication providers, and other services your application requires.
Will you provide API documentation and source code?
Yes. I provide the project source code and can include clear API documentation so you or another developer can understand the available endpoints, request methods, parameters, responses, and authentication requirements.
Can you fix or debug an existing Node.js API?
Yes. I can troubleshoot API errors, broken endpoints, authentication problems, database issues, integration failures, and performance problems in existing Node.js and Express.js backends.
Can you develop a custom API based on my specific requirements?
Yes. Whether you need a simple REST API or a more complex backend architecture, I can structure the endpoints and functionality around your application's specific workflow and requirements.

