Md. is available for hire
Hire Md.Md. Arif Mahmood
Verified Expert in Engineering
Back-end Developer
Dhaka, Dhaka Division, Bangladesh
Toptal member since September 24, 2021
Bio
Arif is a seasoned fintech specialist with deep expertise in Java and Go. Passionate about solving complex problems, he crafts scalable, high-impact solutions for modern businesses. With a proven track record in building core systems for top digital wallets, Arif is ready to bring his talents to Toptal’s elite network.
Portfolio
Pathao
Go, GoLand, PostgreSQL, REST APIs, Apache Kafka, Redis, MongoDB, ACID...
Ghuddy
Java, Spring Boot, PostgreSQL, REST APIs, Amazon EC2, Amazon RDS, Amazon EKS...
Pathao
Go, GoLand, MongoDB, REST, Back-end, OAuth 2, Microservices, PostgreSQL...
Experience
- Spring Boot - 7 years
- Java - 5 years
- Back-end - 5 years
- REST APIs - 5 years
- IntelliJ IDEA - 5 years
- C++ - 4 years
- Go - 3 years
- GoLand - 2 years
Availability
Full-time
Preferred Environment
Go, Java, Spring Boot, Node.js, React, JetBrains, Git, PostgreSQL
The most amazing...
...thing I've built is a core accounting engine for a major Bangladeshi wallet, handling millions of transactions with Go, Kafka, and PostgreSQL.
Work Experience
Senior Software Engineer
2024 - PRESENT
Pathao
- Designed and developed back-end services in Go for PathaoPay, a PSP-licensed wallet, handling millions of secure transactions daily.
- Built and maintained core accounting and settlement services to ensure accurate, real-time ledger updates and financial reconciliation.
- Integrated with 3rd-party payment networks such as MPGS, CyberSource, BEFTN, and NPSB to enable seamless digital payments.
- Implemented Kafka-based asynchronous communication for transaction processing, improving system scalability and reliability.
- Collaborated with cross-functional teams to develop and maintain APIs for user authentication and transaction validation.
- Optimized PostgreSQL queries and database schema to improve performance, resulting in a 30% reduction in transaction processing time.
- Implemented Docker and Kubernetes for containerization and orchestration, streamlining deployment and ensuring environment consistency.
Technologies: Go, GoLand, PostgreSQL, REST APIs, Apache Kafka, Redis, MongoDB, ACID, Kubernetes, Argo CD, GitLab, Git, Payment APIs, Card Payments, PAN Cards, Mobile Wallet, Payment Gateways, IntelliJ IDEA
Lead Back-end Engineer
2022 - 2023
Ghuddy
- Designed and developed back-end services using Java to support Ghuddy’s travel booking platform, ensuring seamless booking and payment processing.
- Implemented secure API integrations with 3rd-party flight, hotel, and car rental services, enabling real-time booking and availability updates.
- Implemented a payment gateway to collect payments for bookings.
Technologies: Java, Spring Boot, PostgreSQL, REST APIs, Amazon EC2, Amazon RDS, Amazon EKS, AWS Fargate, Elasticsearch, IntelliJ IDEA, Java 8
Software Engineer
2021 - 2023
Pathao
- Designed and developed back-end services in Go for PathaoPay, a PSP-licensed wallet, handling millions of secure transactions daily.
- Built and maintained core accounting and settlement services to ensure accurate, real-time ledger updates and financial reconciliation.
- Integrated with third-party payment networks such as MPGS, CyberSource, BEFTN, and NPSB to enable seamless digital payments.
- Implemented Kafka-based asynchronous communication for transaction processing, improving system scalability and reliability.
- Collaborated with cross-functional teams to develop and maintain APIs for user authentication and transaction validation.
- Optimized PostgreSQL queries and database schema to improve performance, resulting in a 30% reduction in transaction processing time.
- Implemented Docker and Kubernetes for containerization and orchestration, streamlining deployment and ensuring environment consistency.
Technologies: Go, GoLand, MongoDB, REST, Back-end, OAuth 2, Microservices, PostgreSQL, Amazon Web Services (AWS), JSON, Software Architecture, Amazon Simple Notification Service (SNS), Lambda Functions, Test-driven Development (TDD), API Integration, Object-oriented Programming (OOP), APIs, Redis, MySQL, Software Integration, Architecture, Back-end Development, Kubernetes, Apache Kafka, Relational Databases, Docker, Payment Gateways, Technical Writing, GitHub, Authentication, Amazon S3 (AWS S3), IntelliJ IDEA
Senior Software Engineer
2021 - 2021
D Money Bangladesh
- Developed microservices to manage user-related functionalities and information such as registration, login, role privileges, profiles, wallets, accounting, refill, and withdrawal.
- Tracked and fixed bugs using Jira and Redmine as reporting tools.
- Fixed bugs and live server issues; worked closely with the customers to solve the problems they were facing.
- Designed the architecture for several features, including the wallet refill and withdrawal of money from the wallet to the banks.
Technologies: Java, Spring Boot, Oracle, Git, GitLab, Postman, Apache JMeter, Spring, REST, Back-end, OAuth 2, Microservices, JSON, Software Architecture, Database Migration, API Integration, Object-oriented Programming (OOP), APIs, Spring JDBC, MySQL, Software Integration, Architecture, Back-end Development, Relational Databases, Payment Gateways, GitHub, Authentication, PDF, Spring Microservice, Amazon S3 (AWS S3), Amazon Elastic Container Service (ECS), Spring MVC, IntelliJ IDEA, Redmine, Java 8
Software Engineer
2020 - 2021
An online freelance agency
- Developed an Android app according to the client's requirement using Java and Flutter.
- Tracked and fixed bugs of the existing application and improved performance by refactoring the code.
- Optimized the run time by identifying bottlenecks in several application codes.
Technologies: Java, Django, Spring Boot, Data Structures, Algorithms, SQL, REST APIs, Java GUI, Spring, REST, JSON, Software Architecture, API Integration, Object-oriented Programming (OOP), APIs, Spring JDBC, JavaScript, HTML, CSS, Back-end Development, Relational Databases, Payment Gateways, Python, GitHub, Amazon EKS, Amazon Simple Queue Service (SQS), IntelliJ IDEA, Java 8, Amazon DynamoDB
Software Engineer
2017 - 2020
D Money Bangladesh
- Conducted requirement analysis and participated in meetings with business teams and stakeholders to define product features and technical scope.
- Researched, architected, and implemented complete back-end architecture for scalable, maintainable financial applications.
- Developed back-end services using Spring Framework to support core wallet functionalities, ensuring reliability and performance.
- Guided team members in feature development by explaining requirements, architecture decisions, and best practices.
- Reviewed team members' code to ensure high standards in scalability, maintainability, and adherence to design patterns.
- Trained junior team members on modern development tools and best practices to elevate overall team performance.
- Conducted research and proof-of-concept work on requested features using emerging technologies to evaluate feasibility and implementation strategy.
- Delivered production-ready back-end modules with thorough test coverage and developer documentation.
- Sent regular status updates to stakeholders, promoting transparency and accountability across teams.
- Updated task progress and issue status in Jira and Redmine to maintain alignment with sprint goals and deadlines.
Technologies: Java, Spring Boot, Oracle, Spring, REST, Back-end, OAuth 2, Microservices, JSON, Software Architecture, API Integration, Object-oriented Programming (OOP), Back-end Development, Payment Gateways, GitHub, Spring MVC, IntelliJ IDEA, Redmine, Java 8
Experience
Pathao Pay
https://pathaopay.com/Pathao Pay is a product of Digital Payments Ltd., a subsidiary of Pathao Ltd. The brand ensures easy, fast, and secure means of owning a digital wallet, changing the way consumers and merchants interact with digital currency.
Pathao Pay was brought to life with a single goal: to create advanced fintech solutions accessible to everyone in Bangladesh and complete the perfect ecosystem for digital payments.
Pathao Pay was brought to life with a single goal: to create advanced fintech solutions accessible to everyone in Bangladesh and complete the perfect ecosystem for digital payments.
Dmoney Wallet
https://www.dmoney.com.bd/Dmoney is a digital payments and services platform with intellectual property (IP) rights for Dmoney software:
• Licensed to operate in all financial streams.
• Dmoney serves both B2C and B2B Market segments.
• Nation's 1st interoperable QR (EMVCo compliant).
• Innovation in B2B supply chain digitization.
• All services in one platform → 360° services.
• International standards in security protocols, Central Bank audited.
• Key strategic partnership across market verticals.
• Licensed to operate in all financial streams.
• Dmoney serves both B2C and B2B Market segments.
• Nation's 1st interoperable QR (EMVCo compliant).
• Innovation in B2B supply chain digitization.
• All services in one platform → 360° services.
• International standards in security protocols, Central Bank audited.
• Key strategic partnership across market verticals.
Ghuddy
https://ghuddy.com/This is a travel tech project that helps users find a suitable hotel or tour according to their requirements. The platform also has a merchant dashboard for hotel management and an admin panel to manage users and merchants. As part of the development team, I helped implement the already established Java-based roadmap.
Education
2013 - 2017
Bachelor's Degree in Computer Science and Engineering
Bangladesh University of Engineering and Technology - Dhaka, Bangladesh
Certifications
MARCH 2023 - PRESENT
Blockchain A-Z: Learn How To Build Your First Blockchain
Udemy
Skills
Libraries/APIs
REST APIs, React, Node.js
Tools
GitHub, IntelliJ IDEA, GoLand, Redmine, Trello, Jira, Git, GitLab, Postman, Apache JMeter, Java GUI, Amazon Simple Notification Service (SNS), JetBrains, Apache Tomcat, Amazon EKS, Amazon Elastic Container Service (ECS), Amazon Simple Queue Service (SQS), AWS Fargate
Languages
Java, Go, Java 8, C++, SQL, Python, JavaScript, HTML, CSS
Frameworks
Spring Boot, Spring, Spring JDBC, Spring Microservice, Django, OAuth 2, Spring MVC
Paradigms
Microservices, REST, Object-oriented Programming (OOP), Test-driven Development (TDD), ACID
Storage
JSON, Relational Databases, MySQL, PostgreSQL, Redis, MongoDB, Databases, Elasticsearch, Amazon DynamoDB, Database Migration, Amazon S3 (AWS S3)
Platforms
Docker, MacOS, Arduino, Oracle, Amazon EC2, Blockchain, AWS Lambda, Amazon Web Services (AWS), Kubernetes, Apache Kafka, Android
Other
Back-end, APIs, Back-end Development, Payment Gateways, Software Architecture, API Integration, Software Integration, Architecture, Authentication, PDF, Windows 10, Data Structures, Algorithms, Software Engineering, Transactions, Amazon RDS, Serverless, Lambda Functions, Technical Writing, File Management, System Design, Payment APIs, Card Payments, PCI DSS, Argo CD, PAN Cards, Mobile Wallet
Collaboration That Works
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
1
Share your needs
Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2
Choose your talent
Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3
Start your risk-free talent trial
Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.
Top talent is in high demand.
Start hiring