Md is available for hire
Hire MdMd Akhlaq Rifat Rahman
Verified Expert in Engineering
Back-end Developer
Winnipeg, MB, Canada
Toptal member since January 26, 2026
Bio
I’m a senior Java back-end engineer with 5+ years of experience building and operating distributed, high-traffic systems in production. I specialize in Java and Spring Boot, designing scalable microservices and event-driven architectures with a focus on performance, reliability, and clean system design. I’ve owned back-end architecture end-to-end, from system design and service boundaries to data modeling, performance tuning, and production stability on AWS using Kafka, Redis, and PostgreSQL.
Portfolio
Toptal
System Design, End-to-end Encryption (E2EE), Java, Python...
RR WINS, LLC
PHP, iOS, Android, Amazon Web Services (AWS), GitHub, Stripe, CodeIgniter...
Technonext Ltd.
Java, System Design, Spring Boot, Redis, New Relic, ELK (Elastic Stack), Git...
Experience
- Amazon Web Services (AWS) - 6 years
- PostgreSQL - 6 years
- Java - 6 years
- Spring Boot - 6 years
- Docker - 4 years
- Microservices - 4 years
- Event-driven Architecture - 3 years
- System Design - 3 years
Preferred Environment
Java, Spring Boot, Microservices, Event-driven Architecture, Docker, CI/CD Pipelines, Large-scale Distributed Systems, Databases, Architecture, Amazon Web Services (AWS)
The most amazing...
...work I've done is building and scaling back-end systems powering research and public-sector platforms, including healthcare systems and an OTA platform.
Work Experience
Senior Back-end Developer
2026 - PRESENT
Toptal
- Designed architecture for a secure multi-tenant messaging and document platform. Defined JWT tenant isolation, RBAC access control, encrypted document storage, real-time messaging, and AWS deployment using ALB, PostgreSQL (RDS), and S3.
- Resolved critical payment gateway issues in a production ride-sharing platform. Debugged third-party payment integration, fixed transaction flow bugs, and stabilized ride payment processing to ensure reliable and secure transactions.
- Resolved critical payment gateway issues in a live ride-sharing platform by debugging third-party payment integration and fixing transaction state handling to restore reliable ride payment processing.
Technologies: System Design, End-to-end Encryption (E2EE), Java, Python, Amazon Web Services (AWS), Debugging, Database Design, System Architecture, Multi-tenant SaaS, API Design, Recommendation Systems, Azure, Data Mining, Webhooks, Refactoring, JavaScript, Node.js, CSS, React, API Integration, REST APIs, Twilio API, Google Sheets, Infrastructure, Kotlin, AWS Certified DevOps Engineer, iOS, Swift, Large Language Models (LLMs), Cloud Infrastructure, Code Review, Stripe API, Web Development, Web, Agentic Workflow Design, LLM Integration, PostGIS, Data Engineering, GIS, Full-stack, Full-stack Development, Responsive Web Design (RWD), User Experience (UX), Mobile App Development, User Interface (UI), Data Visualization
PHP Stripe Payment Back-end Developer
2026 - 2026
RR WINS, LLC
- Fixed several payment-related bugs in the back-end application.
- Fixed auto-fill bugs for Android and iOS. Fixed some buttons and permission-related bugs.
- Android 16KB page support introduced. Updated 10+ library and related codes. Also fixed unnecessary code and reduced the app size from 157 MB to 61 MB.
Technologies: PHP, iOS, Android, Amazon Web Services (AWS), GitHub, Stripe, CodeIgniter, Stripe API, Web Development, Web, Agentic Workflow Design, LLM Integration, PostGIS, Full-stack, Full-stack Development, Responsive Web Design (RWD), User Experience (UX), Mobile App Development, Data Visualization
Senior Software Engineer
2024 - 2025
Technonext Ltd.
- Led a 5-person Java engineering team responsible for core microservices in enterprise-scale OTA and ride-sharing platforms serving high daily traffic.
- Owned system architecture, technical roadmap, and end-to-end delivery while remaining hands-on with Spring Boot services.
- Designed and operated cloud-native microservices using Kafka, Redis, and AWS to ensure high availability and scalability.
- Reduced overall API response time by around 70% across four microservices by introducing Redis caching with TTL-based consistency.
- Established enterprise engineering standards, including CI/CD pipelines, code reviews, and production runbooks, improving release stability.
Technologies: Java, System Design, Spring Boot, Redis, New Relic, ELK (Elastic Stack), Git, Docker, Kubernetes, CI/CD Pipelines, Microservices, Event-driven Architecture, Amazon Web Services (AWS), Architecture, Databases, Cache, Back-end Development, Large-scale Distributed Systems, APIs, Back-end, JSON Web Tokens (JWT), REST, Payments, Database Structure, Docker Compose, PostgreSQL, API Architecture, SaaS, System Architecture, Distributed Systems, SQL, Web Design, Security, Google Cloud Platform (GCP), Software Architecture, Stripe, Customer Relationship Management (CRM), AI Agents, Enterprise Resource Planning (ERP), GitHub, Python, JSON, Machine Learning, API Design, Azure, Data Mining, Webhooks, Refactoring, Node.js, API Integration, REST APIs, Twilio API, Google Sheets, Infrastructure, Kotlin, AWS Certified DevOps Engineer, iOS, Swift, Large Language Models (LLMs), Cloud Infrastructure, Code Review, Stripe API, Web Development, Web, Agentic Workflow Design, PostGIS, Data Engineering, GIS, Full-stack, Full-stack Development, Responsive Web Design (RWD), User Experience (UX), Mobile App Development, User Interface (UI), Data Visualization
Senior Software Engineer
2023 - 2024
Reddot Digital Ltd. (sister concern of Robi Axiata Ltd)
- Served as technical owner for back-end services within a national-scale IoT platform operated by a major telecom group.
- Developed and maintained distributed back-end services using Java, Spring Boot, MQTT, and relational databases.
- Worked closely with multiple teams (product, operations, and business) to support enterprise SLAs and production reliability.
- Led L2 and L3 incident investigation and resolution for latency, data consistency, and integration issues in live systems.
- Contributed to monitoring, performance optimization, and operational stability of long-running enterprise systems.
- Worked on long-running, enterprise-grade systems with strict uptime, data integrity, and operational requirements.
Technologies: Java, Spring Boot, PostgreSQL, Large Data Sets, MQTT, Microservices, Event-driven Architecture, System Design, Amazon Web Services (AWS), Architecture, Databases, Cache, Back-end Development, Large-scale Distributed Systems, APIs, Back-end, JSON Web Tokens (JWT), REST, Payments, Database Structure, Docker Compose, Docker, API Architecture, SaaS, System Architecture, Distributed Systems, SQL, Web Design, Security, Google Cloud Platform (GCP), Software Architecture, Customer Relationship Management (CRM), AI Agents, Enterprise Resource Planning (ERP), CodeIgniter, PHP, GitHub, Android, Python, JSON, Refactoring, API Integration, REST APIs, Twilio API, Google Sheets, Infrastructure, Kotlin, AWS Certified DevOps Engineer, iOS, Swift, Cloud Infrastructure, Code Review, Stripe API, Web Development, Web, Agentic Workflow Design, Data Engineering, GIS, Full-stack, Full-stack Development, Responsive Web Design (RWD), User Experience (UX), Mobile App Development, Data Visualization
Software Engineer
2020 - 2023
Reddot Digital Ltd. (sister concern of Robi Axiata Ltd)
- Developed back-end services for large-scale IoT and telecom platforms using Java, PHP (CodeIgniter), MQTT, and MySQL.
- Built and maintained services for device provisioning, telemetry ingestion, analytics, and payment workflows.
- Integrated messaging and data pipelines to support real-time device communication and event processing.
- Collaborated with cross-functional teams to deliver reliable back-end solutions and support production operations.
Technologies: Java, Migration, PostgreSQL, MySQL, MQTT, Spring Boot, Microservices, Event-driven Architecture, System Design, Amazon Web Services (AWS), Databases, Back-end Development, Large-scale Distributed Systems, APIs, Back-end, JSON Web Tokens (JWT), REST, Database Structure, Docker Compose, Docker, SaaS, System Architecture, SQL, Web Design, Security, Google Cloud Platform (GCP), Customer Relationship Management (CRM), Enterprise Resource Planning (ERP), CodeIgniter, PHP, GitHub, Android, JSON, Refactoring, Node.js, API Integration, REST APIs, Twilio API, Google Sheets, Infrastructure, Kotlin, AWS Certified DevOps Engineer, iOS, Cloud Infrastructure, Code Review, Stripe API, Web Development, Web, Agentic Workflow Design, Full-stack, Full-stack Development, User Experience (UX), Mobile App Development, Data Visualization
Experience
PortYou (Ride-share)
Acted as service owner for core RideShare microservices within a larger distributed platform.
Designed real-time ride matching, ETA estimation, promo management, trip management, and pricing workflows, coordinating across back-end and infrastructure teams.
Led performance tuning and reliability improvements for production systems handling real-time geolocation data.
Designed real-time ride matching, ETA estimation, promo management, trip management, and pricing workflows, coordinating across back-end and infrastructure teams.
Led performance tuning and reliability improvements for production systems handling real-time geolocation data.
FirstTrip.com — OTA Booking Platform
http://www.firsttrip.comI designed and led back-end development for a production OTA platform supporting flight, hotel, and tour bookings. I built and operated a distributed microservices architecture that handled search, booking, pricing, and concurrency control. I also implemented mechanisms to prevent duplicate reservations under high load while optimizing search latency and system reliability for real users.
National Cancer Registry — Government Healthcare Platform
I designed and implemented back-end services for a national-level healthcare registry used for cancer patient tracking and reporting. I built secure, scalable back-end systems supporting data ingestion, validation, and reporting across multiple institutions. The platform was developed under government and medical compliance requirements, prioritizing data integrity, reliability, and long-term maintainability.
Robi IoT Platform — Telecom & Enterprise IoT
https://play.google.com/store/apps/details?id=com.robi.axiata.iotapp&hl=en_CAI worked on back-end systems for a national-scale telecom IoT platform, supporting device provisioning, telemetry ingestion, analytics, and integrations. I built and maintained services that operated under telecom-grade SLAs and reliability requirements, handling real-time device data and long-running enterprise workloads.
Secure Multi-Tenant Messaging & Document Vault Architecture
Client Problem:
The client required a secure communication platform that supports encrypted messaging, document sharing, and strict tenant isolation across multiple organizations.
My Role:
I designed the full system architecture, including security model, infrastructure design, and tenant isolation strategy.
Key Architecture Decisions:
Multi-tenant SaaS architecture with strict tenant isolation
JWT-based authentication with embedded tenant context
Modular monolith back end to reduce operational complexity
WebSocket-based real-time messaging
Encrypted document storage using object storage
RBAC authorization model for tenant users
Defense-in-depth security architecture
Infrastructure:
AWS cloud deployment
Application Load Balancer
PostgreSQL (RDS)
S3 encrypted document storage
Outcome:
Delivered a production-ready architecture blueprint enabling the client to build a secure messaging and document platform with strong tenant isolation and scalable infrastructure.
The client required a secure communication platform that supports encrypted messaging, document sharing, and strict tenant isolation across multiple organizations.
My Role:
I designed the full system architecture, including security model, infrastructure design, and tenant isolation strategy.
Key Architecture Decisions:
Multi-tenant SaaS architecture with strict tenant isolation
JWT-based authentication with embedded tenant context
Modular monolith back end to reduce operational complexity
WebSocket-based real-time messaging
Encrypted document storage using object storage
RBAC authorization model for tenant users
Defense-in-depth security architecture
Infrastructure:
AWS cloud deployment
Application Load Balancer
PostgreSQL (RDS)
S3 encrypted document storage
Outcome:
Delivered a production-ready architecture blueprint enabling the client to build a secure messaging and document platform with strong tenant isolation and scalable infrastructure.
Education
2026 - 2026
Master's Degree in Electrical and Computer Engineering
University of Manitoba - Winnipeg, MB, Canada
2016 - 2019
Bachelor's Degree in Computer Science and Engineering
Islamic University of Technology - Dhaka, Bangladesh
Skills
Libraries/APIs
REST APIs, Stripe API, Stripe, Node.js, React, Twilio API, Google Maps API
Tools
Git, Docker Compose, GitHub, Google Sheets, ELK (Elastic Stack), MQTT, GIS
Languages
Java, SQL, Kotlin, PHP, JavaScript, CSS, Python, HTML, Swift
Frameworks
Spring Boot, JSON Web Tokens (JWT), CodeIgniter
Paradigms
Microservices, REST, API Architecture, Refactoring, Responsive Web Design (RWD), Event-driven Architecture, Database Design
Platforms
Docker, New Relic, Web, Amazon Web Services (AWS), Android, Kubernetes, Apache Kafka, Google Cloud Platform (GCP), Azure, iOS
Storage
PostgreSQL, Database Management Systems (DBMS), MySQL, Databases, Database Structure, JSON, Cache, Redis, PostGIS, Amazon S3 (AWS S3)
Industry Expertise
Web Design
Other
Large-scale Distributed Systems, Software Development Lifecycle (SDLC), Large Data Sets, System Design, Back-end Development, APIs, Back-end, SaaS, System Architecture, Distributed Systems, Software Architecture, Customer Relationship Management (CRM), Enterprise Resource Planning (ERP), API Design, Recommendation Systems, API Integration, Infrastructure, AWS Certified DevOps Engineer, Large Language Models (LLMs), Cloud Infrastructure, Code Review, Full-stack, Full-stack Development, User Experience (UX), Mobile App Development, User Interface (UI), CI/CD Pipelines, Migration, Architecture, Payments, AI Agents, Webhooks, Web Development, Agentic Workflow Design, LLM Integration, Data Visualization, Apache Cassandra, Optimization, Security, Machine Learning, End-to-end Encryption (E2EE), Debugging, Multi-tenant SaaS, Data Mining, Data Engineering, Satellite Images
Collaboration That Works
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