Browse categories
Explore
Fiverr Pro
English
$
USD
I will develop rest apis and backend systems using node js or nestjs
Bernardo Costa
About this gig
Need a reliable backend or API for your web or mobile application?
I can build, fix, integrate, or improve your backend server and expose it through a secure, scalable API. Whether you need a backend from scratch, custom REST APIs, third-party integrations, or help debugging an existing system, I can handle your requirements and architecture.
What I offer:
- Custom REST API & backend development
- API integration & troubleshooting
- Authentication & authorization (JWT, OAuth, RBAC)
- SQL & NoSQL database design
- Webhooks & real-time features
- Payment, AI, email, SMS & third-party integrations
- Data synchronization & automation
- Microservices & scalable architectures
- API documentation & testing
- Cloud deployment & production setup
Why choose me?
- 5+ years of full-stack expertise
- Clean, scalable, secure code with documentation
- Fast delivery & clear communication
- Ongoing support after delivery
- Proven track record with CRMs and payment systems
From a single endpoint to a complete backend system, I can turn your requirements into a production-ready solution.
Please message me before ordering to discuss your requirements and scope.
Get to know Bernardo Costa
Bernardo Costa
Sky is the limit!
- FromPortugal
- Member sinceFeb 2020
- Last delivery1 year
Languages
English, Portuguese
Hello! I'm Bernardo, a senior Software Developer with over 8 years of experience in the tech industry, having worked with various multinational companies. My expertise spans multiple programming languages, including Kotlin, Java, Python, JavaScript, and C#, to name a few. I specialize in developing robust and scalable backend microservices using Kotlin with Spring, ensuring top-notch performance and security. I bring a unique combination of technical prowess and security-focused development to every project.
Other Software Development Services I Offer
FAQ
I have an existing backend. Can you add new APIs or integrations to it?
Yes. I can extend existing backend systems, add new endpoints, integrate third-party APIs, fix bugs, improve performance, and work with your existing architecture.
Do you only develop backend systems?
My main focus is backend and API development. I can also work with Angular, React.js, Next.js, Vue.js, and Tailwind CSS when frontend integration or full-stack development is required.
What technologies do you use?
I primarily use TypeScript with Node.js, Express.js, NestJS, and Next.js for backend development. For frontend work, I use Angular, React.js, Next.js, Vue.js, and Tailwind CSS.
What types of APIs can you develop or integrate?
I work with REST APIs, third-party APIs, webhooks, custom APIs, payment APIs, AI APIs, authentication services, data synchronization, and many other external services.
Can you integrate an API that isn't listed in your Gig?
Yes. If the service provides API documentation or another integration method, I can review it and determine the best approach.
Do you handle authentication and security?
Yes. I can implement JWT, OAuth, API keys, role-based access control, validation, CORS, secure error handling, and other API security requirements.
What if my project is larger than the listed packages?
No problem. Larger or more complex projects can be handled with a custom offer based on your requirements, architecture, and estimated development time.
What do you need from me to get started?
Ideally, provide your requirements, API documentation (if applicable), existing code or repository, expected functionality, and any relevant technical specifications.
How do you communicate during the project?
I maintain clear communication throughout the project and provide updates on progress, technical decisions, and any issues that may affect the scope or timeline.
Do you work on school or college assignments?
I can help with learning, debugging, explanations, architecture guidance, and understanding technical concepts, but I don't complete academic assignments on your behalf.
