You will get Java Developer for REST API Integration with Your Backend
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Project details
If you're building a backend service that depends on external data or functionality, I’ll handle secure and efficient REST API integration using Java. Whether it’s payment, analytics, CRM, or internal APIs – I’ve got you covered.
What You’ll Get:
• Clean and tested Java code for API integration
• Support for authentication (API key, OAuth, JWT)
• Data parsing and mapping to your domain model
• Error handling and retry logic
• Postman collection or usage documentation
What You’ll Get:
• Clean and tested Java code for API integration
• Support for authentication (API key, OAuth, JWT)
• Data parsing and mapping to your domain model
• Error handling and retry logic
• Postman collection or usage documentation
Programming Languages
JavaCoding Expertise
Cross Browser & Device Compatibility, Performance Optimization, SecurityWhat's included $499
These options are included with the project scope.
$499
- Delivery Time 4 days
- Number of Revisions 1
17 reviews
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LR
Luis R.
Jan 7, 2026
Full-Stack Developer Needed to Build MVP for Healthcare Scheduling SaaS (Web App)
Nazariy did an excellent job working on my project. He was professional, reliable, and very responsive throughout the project. Communication was clear, deadlines were respected, and the quality of his work met our expectations. I would definitely recommend Nazariy and the CodePhusion for future projects.
OI
Oleksii I.
Jan 5, 2026
Updating Mailtrap Python SDK
Great quality and communication
LG
Linda G.
Nov 28, 2025
MVP — MCP-based SaaS
We enjoyed working with Nazar and his team, who understood the challenge and worked to build a strong tech product.
MF
Massimo F.
Sep 5, 2025
Backed Development for Upwork
All good: code quality, schedule and communication.
FI
Faran I.
Aug 24, 2025
Web scraping
best developer on upwork
About Nazariy
Java Developer | Spring Boot | Full Stack Developer
100%
Job Success
Lviv, Ukraine - 5:45 am local time
My focus 🎯 is on using Java, Spring Boot, React.js, PostgreSQL, and AWS to deliver reliable, scalable software. As a Java developer, I have delivered dozens of projects across industries and use cases.
My backend work is built entirely with Java. I create secure APIs and microservices using Spring Boot. I have deep experience in system architecture, backend performance, and database design. Every project I take as a Java developer is written with clean, maintainable Java code. I know how to structure services that scale.
As a Java backend developer, I have built and maintained systems for high-load traffic, third-party integrations, and complex business logic. I manage full backend pipelines, from architecture and development to deployment and monitoring. I use Spring Boot and follow best practices every Java developer should apply.
I also work as a full stack Java developer, connecting Java backends with React.js and JavaScript frontends. I create dashboards, user interfaces, and admin tools that are fast, stable, and fully integrated. I know how to deliver full stack features without bottlenecks.
I have led teams as a senior Java developer, mentoring other developers, reviewing Java code, and improving team performance. My clients rely on me not just for development, but also for decisions about architecture, data structure, and deployment strategy. As a Java developer, I care about the full picture.
In most projects, I take the role of a Java spring developer and own the backend infrastructure. I work with Docker, PostgreSQL, REST APIs, and cloud services. I often work independently, taking full responsibility for both backend and frontend parts as a full stack developer.
Being a professional Java developer means I deliver production-ready code, meet deadlines, and communicate clearly. I work well with teams or as a solo contributor. My background as a Java backend developer and Java spring developer allows me to adapt to different project needs.
If you need a Java developer who can work on backend systems, full stack features, or cloud-based platforms, I am ready to help. Whether you need a senior Java developer, a Java backend developer, or a reliable full stack Java developer, I can take your project from idea to production.
🛠️ Core Skills:
- Java developer
- Java backend developer
- Full stack Java developer
- Java spring developer
- Spring Boot microservices
- React.js and JavaScript
- PostgreSQL, AWS, Docker
Let’s talk if you need a results-driven Java developer to join your team or take over delivery.
‼️ Message me for a free 40-minute consultation ‼️
Steps for completing your project
After purchasing the project, send requirements so Nazariy can start the project.
Delivery time starts when Nazariy receives requirements from you.
Nazariy works on your project following the steps below.
Revisions may occur after the delivery date.
Kickoff & Scope Confirmation
We align on API details, endpoints, and backend setup.
API Integration Development
I implement the API client, map responses, and integrate with your backend logic.