You will get backend bugs fixed fast with clean, tested code
Project details
You will get your backend bug fixed properly — not a quick patch that breaks something else, but a real fix with tests and a clear explanation of what went wrong.
I have debugged payment systems at Santander Bank and untangled legacy codebases in telecom. I work with Java/Spring Boot primarily but also fix issues in Node.js, Python, and Supabase backends.
Every fix includes: the solution, a test that proves it works, and a written root cause explanation. If I spot other problems while fixing yours, I flag them for free.
I have debugged payment systems at Santander Bank and untangled legacy codebases in telecom. I work with Java/Spring Boot primarily but also fix issues in Node.js, Python, and Supabase backends.
Every fix includes: the solution, a test that proves it works, and a written root cause explanation. If I spot other problems while fixing yours, I flag them for free.
Programming Languages
Python, Java, TypeScriptCoding Expertise
Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$80
|
Standard
$250
|
Advanced
$500
|
|---|---|---|---|
| Delivery Time | 2 days | 5 days | 7 days |
Number of Revisions | 1 | 2 | 2 |
Bug Investigation | |||
Fix Documentation | - | ||
Detailed Code Comments | - | - |
Optional add-ons
You can add these on the next page.
Fast Delivery
+$30 - $100
Additional Revision
+$20
Fix Documentation
(+ 1 Day)
+$30
Detailed Code Comments
+$50
Automated test coverage
(+ 2 Days)
+$80
Performance profiling
(+ 3 Days)
+$120
Post-fix monitoring 7 days
+$50Frequently asked questions
About Volodymyr
Payment & API Backend Engineer | Java, Spring Boot, Ex-Banking
Alicante, Spain - 8:13 pm local time
I specialize in backend systems where failure means lost revenue: payment processing, API integrations, and microservice architectures for SaaS products and growing startups.
What I've shipped:
→ Santander Bank: Built instant payment features that cut transaction processing time by 12%, coordinating 8 cross-functional teams across 4 releases
→ IoT (Friendly Technologies): Decomposed a legacy monolith into 8 Spring Boot microservices - deployment time down 60%, test coverage up to 80%
→ Mobile Platform (Simbio): Architected a booking backend handling 500+ daily transactions with real-time WebSocket chat, reducing server response times by 35%
→ Workflow Automation: Integrated Flowable BPMN into enterprise systems, cutting 40% of manual process steps
How I work: I take your requirements, ask the right questions upfront, deliver clean code with tests, and communicate progress without you having to chase me. Available 10–30 hrs/week with EU timezone overlap.
Stack: Java 8–25 · Spring Boot · PostgreSQL · Docker · Kubernetes · AWS (ECS, RDS, S3) · Kafka · RabbitMQ · Stripe API · Supabase · GitHub Actions
Message me with a brief description of your project - I'll reply with a specific plan of how I'd approach it, not a generic pitch.
Steps for completing your project
After purchasing the project, send requirements so Volodymyr can start the project.
Delivery time starts when Volodymyr receives requirements from you.
Volodymyr works on your project following the steps below.
Revisions may occur after the delivery date.
Reproduce the bug
I set up your project locally, reproduce the issue, and confirm I understand the root cause. I message you with my findings before making changes.
Fix and test
I implement the fix, write tests to cover the bug scenario, and verify nothing else broke. You get a PR with clear description of what changed and why.