Available for remote work

Java Backend
Developer.
Full Remote.

I build production-grade APIs, payment systems, and secure backends with Java 21 & Spring Boot 3. From zero to Dockerised VPS deployment. Clean code, real deadlines, no excuses.

Get in touch → See my work
2+
Years production experience
3
Languages (RU / PL / EN)
<1h
Average response time
100%
Remote, any timezone

About

I am a Java Backend Developer specializing in Spring Boot 3, Java 21, PostgreSQL and Docker. I design and build production-ready backend systems including REST APIs, authentication systems, payment integrations and scalable infrastructure. 2+ years of commercial experience delivering systems to real users.

Experienced in building secure systems with JWT authentication, rate limiting, fraud prevention, and full deployment pipelines using Nginx and Docker on Linux VPS environments. I've shipped payment systems, e-commerce platforms, and mission-critical backends.

Available for remote work worldwide. Focused on backend engineering, API design and system architecture. Trilingual: Russian, Polish, English.

// hiring information

Work Terms & Availability

What you need to know before reaching out.

FULL-TIME

$2,500 - $3,500/mo

  • ✓ Full remote, any timezone
  • ✓ Flexible hours (async-first)
  • ✓ <1hr response time
  • ✓ Multi-month projects
FREELANCE / CONTRACT

$35 - $45/hr

  • ✓ Per-project or hourly
  • ✓ 2-week to 6-month engagements
  • ✓ Bug fixes, features, architecture
  • ✓ Invoice + contract via Upwork
WHAT YOU GET

Standard

  • → Clean, documented code
  • → Source code ownership
  • → GitHub repository
  • → Weekly progress updates

Work Preferences

Availability
Immediate (open to start next week)
Work Schedule
UTC+1 to UTC+8 preferred, flexible
Contract Length
Min 2 weeks, no upper limit
Project Type
Backend, full-stack, architecture
Industries
SaaS, fintech, e-commerce, B2B
Not Interested In
Cryptocurrency, gambling, MLM
Java 21 ·Spring Boot 3.x ·Spring Security ·JWT Auth ·PostgreSQL ·Docker ·REST API ·JPA / Hibernate ·Nginx ·OpenAPI ·TDD ·Rate Limiting ·Java 21 ·Spring Boot 3.x ·Spring Security ·JWT Auth ·PostgreSQL ·Docker ·REST API ·JPA / Hibernate ·Nginx ·OpenAPI ·TDD ·
// what i build

Services

Three things I do well. All delivered remotely. All with source code and documentation.

01
⚡
Backend API Development

Full REST API from scratch — schema design, JWT auth, role-based access, validation, error handling, Swagger docs. Production-ready on day one.

Spring BootJWTPostgreSQLDocker
02
🔐
Security & Fraud Prevention

Payment gateway integration, webhook handling, rate limiting, audit logging, reCAPTCHA, Sentry monitoring. Built this stack end-to-end commercially.

Bucket4jStripe webhooksAudit LoggingSentry
03
🐛
Bug Fixing & Debugging

Spring Boot crashes, JPA N+1, auth issues, Docker failures, performance problems. I find the root cause — not just the symptom. Fixed or no charge.

Any Spring versionRoot cause analysisFast turnaround
// tech stack

What I work with

Tools I've shipped to production, not just read about.

☕Java 21Core
🍃Spring Boot 3.xFramework
🔒Spring SecurityAuth
🐘PostgreSQLDatabase
🐳DockerDevOps
🔁FlywayMigrations
📡REST / OpenAPIAPI Design
🌐NginxInfra
🧪JUnit 5 / MockitoTesting
📊SentryMonitoring
⚙️Maven / GradleBuild
🔗Webhooks / SMTPIntegrations
// projects

Selected work

Two projects built end-to-end. Real requirements, real deployment.

Commercial · 5+ months · Full Cycle
Elixir SportShop — E-commerce Platform

Full-cycle e-commerce backend: product catalog, cart, order lifecycle, payments, fraud prevention, and monitoring. Deployed on Linux VPS with Docker Compose and Nginx.

  • JWT auth with role-based access (customer / admin), Flyway migrations
  • Payment gateway integration with webhook handling and full transaction audit log
  • Fraud layer: rate limiting (Bucket4j), reCAPTCHA v3, request validation, Sentry
  • Multi-service Docker Compose + Nginx reverse proxy + multi-stage builds
  • Integrated Cloudinary, Telegram Bot alerts, SMTP — plus Next.js frontend
Java 21Spring Boot 3.xPostgreSQLJWTBucket4jDockerNginxSentry
GitHub ↗
Team · Backend · Deputy Scrum Master · Diploma
Wdrozeniowy — Full-Stack Monorepo

Three-service monorepo (Java backend, Next.js frontend, Node.js gateway) built as a team diploma project. Backend + deputy Scrum Master role in parallel.

  • REST API + database schema in Spring Boot 3 with Spring Security and JWT
  • Docker + Docker Compose for all services; WebSocket (Socket.io) between gateway and clients
  • Business logic covered with JUnit 5 + Mockito, TDD approach
Java 17Spring Boot 3.xH2JWTSocket.ioDockerJUnit 5
GitHub ↗
// working with me

What you can expect

Honest scoping
I'll tell you upfront if something isn't feasible or will take longer than you expect. No surprises after you've paid.
Clean, documented code
You receive commented, readable code. Not a black box. You should be able to maintain it without me.
Remote-native workflow
Async by default. GitHub for code, clear updates, no need to sync timezones for every question.
Under 1-hour responses
During working hours, I respond fast. If I'm unavailable, I'll say so in advance.
// let's work together

Ready to Hire?
Available Now.

Available for full-time remote positions ($2.5k-3.5k/mo) and freelance contracts ($35-45/hr). Start next week. Response within 60 minutes guaranteed.

✉ Ivan.Yemtseu@icloud.com ✈ Telegram @emtsevv 🔗 LinkedIn Profile ⌨ GitHub Portfolio

// Typically respond within 60 minutes · Remote worldwide · Open to relocation discussions

Java Backend Developer - Ivan Yemtseu

Experienced Java Backend Developer with 2+ years of production experience. Specialized in Spring Boot 3, Java 21, PostgreSQL, Docker, REST APIs, JWT authentication, and payment systems integration.

Contact Information

Skills

Work Experience

2+ years commercial production experience building backend systems

Availability & Compensation

Languages

Work Preferences