I will fix bugs and develop rest apis in java spring boot

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fengquanxian
F
fengquanxian
Fengquan Xian
fix bugs and develop rest apis in java spring boot
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fix bugs and develop rest apis in java spring boot

About this gig

Hi, I'm a backend developer with 10 years of experience in Java and Spring Boot.


I help businesses fix bugs, build REST APIs, and ship features fast.


WHAT I CAN DO:

Fix bugs in your existing Spring Boot project

Build new REST APIs (CRUD, auth, file upload, payment)

Database design & optimization (MySQL, PostgreSQL, Redis)

Integrate third-party APIs (Stripe, PayPal, SMS, OAuth)

MyBatis / JPA / Hibernate

JWT authentication, role-based access

Excel import/export (large dataset, formula, multi-sheet)

Performance tuning (slow SQL, N+1, caching)



WHY ME:

10+ years building production systems (e-commerce, CRM, BI dashboards)

Clean, documented code you can maintain

Fast reply within a few hours (GMT+8)

Free 7-day post-delivery support


WORK PROCESS:

1. You describe the bug or feature

2. I review your code/requirements and quote

3. I fix/develop and send you a working version

4. Free revision until you're happy


Please message me BEFORE ordering so I can confirm scope and timeline.


Let's ship it!

  • Expertise

    • Debugging
    • Performance
    • Databases

  • Programming language

    • Java

  • Frontend framework

    • Vue.js

  • Backend framework

    • Spring

Get to know Fengquan Xian

Fengquan Xian

Senior Java Spring Boot Developer specializing in Payment and Web3

  • FromChina
  • Member sinceJun 2026

  • Languages

    Chinese, English
Hi, I'm Fengquan — Senior Full-Stack Developer with 10+ years in Java/Spring Boot and 5+ years in Vue.js. I help startups ship backends fast, focused on PAYMENT INTEGRATION and WEB3. Backend: Java, Spring Boot, Redis, MySQL Frontend: Vue 3, TypeScript Payment: Stripe, PayPal, Alipay, WeChat Pay Web3: USDT/USDC, ETH/BSC/Polygon, MetaMask, WalletConnect Shipped 2 Web3 platforms (USDT-pegged stablecoin + card-issuing). What you get: - Clean, documented code - Reply within hours (GMT+8) - Sandbox-first delivery - Free post-delivery support Message me BEFORE ordering. Let's ship it!

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