Tasfik Rahman
Verified Expert in Engineering
Java Developer
Dhaka, Dhaka Division, Bangladesh
Toptal member since July 21, 2026
Tasfik is a back-end software engineer with years of experience building scalable, cloud-native systems for US enterprise platforms and national systems serving 20M+ users. Specializing in Java, Spring Boot, and AWS, he has designed event-driven payments back ends, led complex data migrations, and delivered performance gains of 90%+. He owns projects end-to-end, from technical design to production. Let's connect.
Portfolio
Experience
- Java - 5 years
- JavaScript - 5 years
- Spring Boot - 5 years
- PostgreSQL - 4 years
- MySQL - 4 years
- React - 4 years
- Amazon S3 (AWS S3) - 2 years
- AWS Lambda - 2 years
Work Experience
Software Engineer
MarginEdge
- Designed and shipped a greenfield event-driven payments back end using AWS Lambda, EventBridge, SQS/SNS, and DynamoDB, lifting feature adoption by 35% across 1,000+ clients.
- Integrated third-party payments and Plaid, delivering card vaulting, refunds, and NACHA processing for a platform handling millions of daily transactions.
- Led a brownfield PostgreSQL-to-DynamoDB migration using an outbox pattern with auditing, reducing production data drift by 90%.
- Secured RESTful APIs with OAuth 2.0 / OpenID Connect and implemented multi-factor authentication via Auth0 across microservices, owning delivery from technical design to deployment.
- Instrumented services with real-time dashboards and alerts in AWS CloudWatch, Prometheus, and Grafana, proactively resolving critical infrastructure gaps and API failures.
Software Engineer
Dynamic Solution Innovators Ltd.
- Architected Java and Spring Boot microservices for UNICEF's national education platform, designed to serve 20M+ students and 800K teachers.
- Optimized complex SQL queries and added strategic database indexes on a live system, cutting critical data-fetch times from 50+ seconds to under 4 seconds.
- Built a QR-based attendance-tracking module end-to-end, integrating front-end scanners with back-end APIs and reducing manual operational workload by 80%.
- Performed testing using Junit for Java unit testing, Cypress for end-to-end testing, and Storybook for React component development.
- Configured automated CI/CD pipelines with Jenkins and containerized services using Docker, Kubernetes, and Helm across production clusters.
- Engineered distributed storage improvements that raised data availability to 99.9% and deployed high-traffic modules, including registration and online fee payments.
Project History
Full-stack Authentication Application
Education
Bachelor's Degree in Computer Science and Engineering
Military Institute of Science and Technology - Dhaka, Bangladesh
Certifications
Rest API (Intermediate) Certificate
HackerRank
Claude Code in Action
Anthropic
Jenkins
KodeKloud
Skills
Libraries/APIs
React, Node.js
Tools
Git, GitHub, Amazon Simple Notification Service (SNS), Amazon Simple Queue Service (SQS), Jenkins
Languages
JavaScript, Java, C++, CSS
Frameworks
Spring Boot, Hibernate, JPA
Paradigms
Microservices, Clean Code, Database Design
Platforms
AWS Lambda
Storage
Amazon S3 (AWS S3), PostgreSQL, MySQL, MongoDB
Other
Distributed Systems, System Design, Data Architecture, Software Development Lifecycle (SDLC), Vulnerability Scanning, RESTFul APIs, Website Maintenance, Problem Solving, Agentic AI
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