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I will build a secure fintech payments backend integration
Hasnat Ahmed
About this gig
I help businesses integrate secure, production-ready payment and fintech backends into their existing products. Whether you need a single payment gateway connected (Stripe, PayPal, Razorpay) or a full transaction platform with ledgers and reconciliation, I build it directly into your current stack. What I deliver: payment gateway integration and checkout flows, webhook handling for payment events, refunds/chargebacks logic, transaction database design, fraud/risk checks, and clean API documentation. Tech stack: Node.js/Express, Java, Python, PostgreSQL/MySQL, REST APIs, Stripe/PayPal/Razorpay SDKs. Security is non-negotiable for money-moving systems - I follow PCI-DSS-aware practices, idempotent transaction handling, and add logging/alerting for production trust. You get full source code, documentation, and post-delivery support. Message me with your stack and what you need connected.
Get to know Hasnat Ahmed
Hasnat Ahmed
Full Stack Spring Boot and AI Automation Developer
- FromPakistan
- Member sinceMar 2022
- Avg. response time1 hour
- Last delivery7 months
Languages
English
Hi, I am Hasnat Ahmed, a full-stack and backend developer with 2+ years of experience building web applications, backend systems, and AI-powered automation. I specialize in Spring Boot and Java microservices, MEAN/MERN stack development, and AI/chatbot automation integration. Core skills: Java, Spring Boot, Node.js, React, Angular, Python, REST APIs, and databases (MySQL, MongoDB, PostgreSQL). I deliver end-to-end projects with clean code and clear communication. Quality and your time are my top priorities.
My Portfolio
FAQ
Which payment gateways can you integrate?
Stripe, PayPal, Razorpay, and most major gateways with public APIs. I can also work with regional or custom payment processors.
Do you handle PCI compliance and security?
Yes. I follow PCI-DSS-aware practices - tokenized card data, idempotent transactions, and secure webhook verification.
Can you migrate our transaction data to the new system?
Yes, I can design a migration plan for existing transaction/customer data with validation to avoid data loss or duplication.
What information do you need to get started?
Your current backend/stack, which payment provider(s) you use or want, and what the integration needs to do (checkout, refunds, subscriptions, etc).
