Md Mostafizur Rahman, Developer in Dhaka, Bangladesh
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Md Mostafizur Rahman

Verified Expert  in Engineering

Software Developer

Dhaka, Bangladesh
Toptal Member Since
September 27, 2022

Mostafizur is a senior back-end developer with over seven years of experience in software development and management with Ruby on Rails. He has substantial knowledge of the travel industry's web services and specializes in building RESTful back-end APIs and integrating third-party APIs with appropriate authentication, validations, and optimized logic. His expertise is maintaining the coding principle, writing code using the test-driven development approach, and following layered architecture.


Ruby, Ruby on Rails (RoR), RESTful Microservices, Microservices Architecture...
1Password, 3D Secure 2.0, Ruby, Agile Sprints, API Design, Amadeus...
1Password, Ruby, RubyMine, Ruby on Rails 4, Ruby Gems, Ruby on Rails API...




Preferred Environment

Ruby, Ruby on Rails (RoR), RESTful Microservices, Software Development, API Design, RSpec, Code Review, SOAP, PostgreSQL

The most amazing...

...thing I've developed is a travel industry REST API solution that provided millions of results on the availability of flights, hotels, and cars per day.

Work Experience

Principal Software Engineer

2022 - PRESENT
  • Managed multiple projects as a project manager for different clients and products.
  • Contributed to architectural decisions in various RESTful approach projects.
  • Defined project and database architecture for a new Rails-specific project.
  • Ensured the consistent delivery of Rails-specific projects.
Technologies: Ruby, Ruby on Rails (RoR), RESTful Microservices, Microservices Architecture, SOAP, RSpec, PostgreSQL, OAuth 2, JSON, XML, API Documentation, API Design, Test-driven Development (TDD), Git, GitHub, Bitbucket, GitHub Actions, Code Review, gRPC, RabbitMQ, Semantic Logger, Google Cloud Platform (GCP), Heroku, 3D Secure 2.0, CircleCI, GrapesJS, VCR, Object-oriented Programming (OOP), MVC Design, Java, Android, Slack API, OS X, Jira, Rollbar, 1Password, Software Development, MacOS, Slack, G Suite, Google Meet, Trello, RubyMine, Programming, Data Structures, Algorithms, Search Algorithm Design, Algorithm Design, Database Management Systems (DBMS), Software Engineering, REST, Encryption, Team Mentoring, Back-end, Amadeus, Travelport, APIs, Ruby on Rails 4, API Integration, Microservices, API Architecture, Software Architecture, Software Design, REST APIs, Integration

Lead Software Engineer

2019 - 2022
  • Created a booking tool's back end for international travel agencies to create and manage bookings for customers and corporate travelers used by more than 1,000 travel agencies worldwide.
  • Received certification in API development from major API providers, such as GDS, NDC, and British Airways.
  • Built an application back end that can manage service management for a bike rental company with various types of asset management and other features.
  • Managed the project E2E to serve B2B customers. Defined business specifications, technical specifications, and suggestions on wireframes.
  • Performed all sorts of communication (technical and business) between API suppliers and the team. Also handled performance stakeholder communication to deliver expected features.
Technologies: 1Password, 3D Secure 2.0, Ruby, Agile Sprints, API Design, Amadeus, API Development, API Documentation, API Integration, APIs, gRPC, Ruby on Rails 4, Ruby on Rails API, Ruby on Rails 5, Ruby on Rails (RoR), Agile Project Management, Communication, Client Management, MacOS, Slack, API Architecture, Software Architecture, Software Design, REST APIs, Integration

Senior Software Engineer

2017 - 2019
  • Developed a booking and post-booking normalized RESTful API that collected the availability and booking details of global flights, hotels, and rental cars from global distribution systems (GDS), the new distribution capability, and other sources.
  • Analyzed and modified the legacy web services for different suppliers that supported only Simple Object Access Protocol (SOAP) and developed an app that used the normalized REST API.
  • Managed a team of five to seven people. Assigned tasks to them and ensured consistent delivery by helping them achieve their goals.
Technologies: 1Password, Ruby, RubyMine, Ruby on Rails 4, Ruby Gems, Ruby on Rails API, Ruby on Rails (RoR), Travelport, Amadeus, Sabre Global Distribution System, Global Distribution Systems (GDS), NDC, RSpec, APIs, API Design, API Development, Microservices, REST, SOAP, XML, JSON, Microservices Architecture, Rollbar, CircleCI, GitHub, GitHub Actions, API Integration, Mentorship, Team Mentoring, Agile Sprints, Code Review, VCR, MacOS, Slack, API Architecture, REST APIs, Integration

Software Engineer

2015 - 2017
  • Made an eCommerce website using a Spree or Solidus solution for a Swiss brand with more than 1,000 transactions daily.
  • Enhanced experience in Ruby on Rails development and focused on RESTful API development.
  • Onboarded in the world of GDS to integrate the API for Galileo, Amadeus, and Sabre.
  • Handled multiple RoR projects from scratch. Provided 100% test coverage using RSpec.
  • Practiced code review from a quality, security, and linter perspective.
Technologies: Ruby, Ruby on Rails 4, Ruby on Rails API, Ruby on Rails (RoR), RESTful Microservices, REST, SOAP, SoapUI, RSpec, PostgREST, OAuth 2, JSON, XML, API Documentation, Test-driven Development (TDD), GitHub, Code Review, RabbitMQ, VCR, Global Distribution Systems (GDS), NDC, eCommerce, MacOS, Slack, REST APIs

Software Engineer

2014 - 2015
Samsung Research & Development Center
  • Developed, updated, and leased new features for Samsung mobile devices.
  • Designed and implemented a set-up wizard embedded in the email app of Android.
  • Monitored and fixed bugs using product lifecycle management (PLM) as a reporting tool.
  • Tracked, updated, and fixed any Samsung social network services (SNS)—Facebook and Twitter—built-in app updates and issues.
Technologies: Java, Android, TortoiseSVN, Perforce, JavaScript, Tizen, Product Lifecycle Management (PLM), Software Development, Code Review, Back-end, Amadeus, Travelport, APIs, Ruby on Rails 4

Bike Servicing and Management Platform

Developed a Swiss bike rental company's application's back end to manage their bikes.

The application's primary purposes were onboarding new vehicles into the platform, managing different inventory, and managing the servicing of the bikes. Additionally, the app provided warehouse management, platform user management, and can display a comprehensive report graphically.

Implemented in the project was a REST API to create a mobile application for better service management. The REST API was designed and delivered to produce various reports and historical data quickly.

I led the project and was one of the core individuals that planned the whole architecture and developed the back-end portion.

To view additional details about this project:
Password: 123456
ENV: Staging

Reservations Management System for Flights, Hotels, and Rental Cars
The API documentation for flight content suppliers (GDS, NDC, airlines), hotels, and car rental suppliers had been investigated and implemented with either REST or SOAP. As all suppliers differ, the API structure, layout, response, and requests differ. The project involved consuming those APIs to expose a normalized fixed response to the customer. Customers would consume only one REST API to receive the content from all the different suppliers.

The challenges comprised managing different requests, authentication processes, sessions, etc., for those varying suppliers. Also, as the documentation was not enriched, finding the right way to consume those APIs was challenging.

In this project, the codebase had been divided into different layers and services so that every layer and service would be responsible for various purposes. For example, layers for accepting the customer request, validating the request, converting the customer request to a supplier-specific request, making requests to a different supplier (a parallel process), mapping layer, data storing layer, exception handling layer, response structuring layer, and finally, a response layer.

Vehicle Tracking System

The project entailed building a web application to track the different vehicles using the API provided by the vehicle tracking device. It was an admin-based app. The user would not have access to this platform.

Organization-authorized personnels could perform the following operations:
1. Add a new vehicle into the system
2. See the list of vehicles with essential details
3. Visualize all the vehicles on the map
4. Select a specific vehicle and check the status, position, and other details of that vehicle
5. Turn on the alarm using the 'find vehicle' button via the tracking device placed on the vehicle
6. Retrieve essential information about the vehicle, including power status, speed, temperature, battery, connection, odometer, distance, charging status, etc.
7. Set the max speed of the vehicle
8. Turn on or off the power of the vehicle
9. Add new users to the platform for proper management
10. Manage the existing users

Since it was a role-based application, not all users could perform all the tasks; only the authorized user could perform privileged actions.

I designed the back-end architecture and developed the entire back end, including the project specification and remote device tracking API integration.

eCommerce Website for a Swiss Clothing Agency
An eCommerce website that was developed with Spree Commerce or Solidus. I built the back end to load all product data from a legacy system and worked with front-end developers to display it. The application accepted different types of payment options, including invoice and post-finance.

Credit Card Vault

A highly confidential application with some essential features and functions such as:
1. Storing customers' credit card details.
2. The customer can use the stored credit card when purchasing any item.
3. If the customer wanted to use a saved card, the vault performed all the communication with the third party for a successful payment.
4. The application only maintains the payment process. It does not emphasize the third party or any other aspect of the transaction.

My responsibility was to create the system to fetch the credit card and send it to the appropriate third party to make the successful payment.

The project was Self-Assessment Questionnaire D (SAQ D) certified, and I am also a Payment Card Industry Data Security Standard (PCI-DSS) certified member.

Ferry Rental System Back-end API

Developed a SOAP API system based on FerryGateway standard protocol to deliver ferry content to customers. I was responsible for the architectural design of the back-end API, flow management, and SOAP API design planning and development.

A REST Client to Consume a REST API

The project was the innovation of a Ruby gem to consume the REST API of a rental management system. I developed the Ruby gem with the help of Ruby gem rest-in-peace and Faraday, which resulted in this communication gem.

A Ruby Gem to Create SOAP APIs

Creating a SOAP API has become challenging recently. I developed a Ruby gem to generate the SOAP API with a Web Services Description Language (WSDL) file for any project if required. The Ruby gem helped to maintain the structure of SOAP APIs.

A Ruby Gem to Report Real-time Errors to Rollbar

A Ruby Gem that tracked different types of real-time system exceptions and reported them to Rollbar Inc. so that the development team could get the update of any system exception and follow them. The project allowed the action to be performed directly with Rollbar's integration, but the Ruby gem helped to manage it consistently with a proper backtrace and metadata reporting.

I developed the Ruby gem.
2009 - 2014

Bachelor's Degree in Computer Science and Engineering

Rajshahi University of Engineering & Technology - Rajshahi, Bangladesh

2006 - 2008

Higher Secondary Certificate (HSC) in Science

Rajshahi Government City College - Rajshahi, Bangladesh


Rollbar, REST APIs, Slack API, Ruby on Rails API, PostgREST, API Development


Slack, G Suite, GitHub, Jira, Trello, RubyMine, RSpec, Git, VCR, Algorithm Design, Bitbucket, RabbitMQ, Semantic Logger, CircleCI, TortoiseSVN, Perforce, SoapUI, Sabre Global Distribution System


Ruby on Rails (RoR), GrapesJS, Ruby on Rails 4, OAuth 2, gRPC, Ruby on Rails 5


Ruby, XML, Assembly Language, Java, JavaScript


Microservices Architecture, REST, Microservices, Object-oriented Programming (OOP), Test-driven Development (TDD), MVC Design, API Architecture, Agile Project Management


JSON, Database Management Systems (DBMS), PostgreSQL


MacOS, OS X, 1Password, Google Cloud Platform (GCP), Heroku, Android, Tizen


Programming, Software Development, RESTful Microservices, API Documentation, API Design, Back-end, Integration, Google Meet, Data Structures, Software Engineering, SOAP, Code Review, Product Lifecycle Management (PLM), Team Mentoring, Search Algorithm Design, Algorithms, Amadeus, Travelport, APIs, API Integration, Software Architecture, Software Design, Electrical Engineering, Artificial Intelligence (AI), Systems Analysis, Computer Networking, Neural Networks, GitHub Actions, 3D Secure 2.0, Encryption, Microprocessors, Higher Education, Global Distribution Systems (GDS), NDC, eCommerce, Ruby Gems, Mentorship, Agile Sprints, Communication, Client Management

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