Sadiqul Islam
Verified Expert in Engineering
Software Developer
Dhaka, Dhaka Division, Bangladesh
Toptal member since February 13, 2021
Sadiqul is a passionate developer with over 12 years of overall experience, including several successful software development projects like fintech, ride-share, eCommerce, telco, and more. He finds development to be a style of art—the art of data structure, the art of algorithms, the art of design patterns, the art of communication with colleagues, and the art of delivering the product.
Portfolio
Experience
- PHP - 10 years
- JavaScript - 7 years
- Java - 7 years
- React - 7 years
- Python - 7 years
- Symfony - 6 years
- Node.js - 5 years
- Django - 4 years
Preferred Environment
MacOS, PyCharm, WebStorm, Jira, Linux
The most amazing...
...thing I have developed is a fintech core that handles banking for millions of customers.
Work Experience
Senior Software Engineer
SimpleTire, LLC
- Transformed architecture from monolithic to microservice (developed Rest APIs), including authentication (single sign-on).
- Integrated dozens of payment services, including Braintree, PayPal, Affirm, Acima, Klarna, Katapult, Google Pay, Apple Pay, and Venmo.
- Reduced 70% of Amazon RDS (Amazon Aurora) load. Made APIs lightning fast.
Senior Developer
A European FinTech Company
- Rewrote the core authentication (including 2FA) from old PHP code to Python.
- Implemented anti-money laundering features (including complex algorithms and API endpoints for AI).
- Upgraded account holder's admin panel with advanced search strategies and query and schema optimization.
- Wrote several documents and examples in Atlassian Confluence to share knowledge among the teams.
Senior Software Engineer
United States Transit Funding
- Built multi-merchant level transportation network, rideshare APIs, and a web and mobile app.
- Developed a ticket booking system including multiple root and buses feature.
- Updated and refactored a legacy app from Symfony 2.0 to 3.0.
- Onboarded and mentored developers and also set priorities tasks by importance and urgency.
Software Engineer
FishVerify
- Developed the back end and API with Spring with test cases.
- Kept track of the user device id to prevent manipulate the duplicate trial.
- Implemented premium feature and trial period, including payment management.
Full-stack Engineer
Legends Lair Ltd
- Built a cryptocurrency exchange platform's APIs from scratch.
- Designed and planned the whole architecture with the team.
- Hunted and fixed bugs. Wrote unit tests and functional tests that covered all features, including edge cases.
Full-stack Developer
Neuro Tech Galaxy Limited
- Developed a large-scale eCommerce and product management system.
- Built multiple web scrapers for competitor analytics to get the price, offer, and sales comparison.
- Developed a Cron task (applying some algorithms) to automatically set the price and offer to maximize profits of over 150,000 books.
- Mentored four developers and coached office staff to operate the system.
Developer
Freelance
- Developed an Agile coach app using Ionic framework and Laravel with multiple payment methods.
- Awarded TADHack National Champion in 2015. Built a telco app using hSenid API.
- Developed an API for hiring and reserving vehicles.
- Mentored, recruited, interviewed, tested, and motivated developers.
Experience
eMotorcoach
For end customers:
Find the perfect match for your trip using our rich resources and save your valuable time and money by comparing bus companies or ride-shares.
For companies:
eMotorcoach helps your customers book and securely pay for their trip through our innovative and secure reservation management system.
Also, it offers an advanced chatting system for user/driver share location, map, photo of a nearby place, video, voice, or text. (Some of those features were later included in Uber).
It's a complete solution for either ticket bookings or ride-shares.
FishVerify
https://www.fishverify.comJust take a picture with your phone’s camera or upload an existing image to enjoy species identification within seconds.
Rules & Regulations:
Learn local saltwater and freshwater regulations as well as other helpful facts like bag limit, size limit, state record, season, measure, and edibility.
Marine Weather:
Current marine weather including wind, waves, tides, air and water temp, barometric pressure, and more.
Instant Identification:
Import photos or live scan. FishVerify uses the latest in AI to identify your catch.
Catch Log & Catch Map:
FishVerify automatically charts the GPS location of your catch as well as marine weather.
Handyman
https://github.com/SadiqUltra/handymanHandymen can create an account and post their services with their contact number and address (and city).
Regular users can search for a handyman or a service nearby.
Tech used:
- Go
- GraphQL
- PostgreSQL
- Docker
- Kubernates
- pgadmin
- Jwt
Education
Bachelor's Degree in Computer Science and Engineering
Chittagong University of Engineering and Technology - Chittagong, Bangladesh
Certifications
Stripe Professional Payments Developer
Stripe
Stripe Professional Billing Developer
Stripe
Building AI Agents and Agentic Workflows
IBM | via Coursera
Machine Learning
Stanford University | via Coursera
React
Udacity
Skills
Libraries/APIs
React, Node.js, Stripe API, Stripe, React Testing Library, React Redux, Fabric, Vue, Socket.IO, Google Maps API, Google API, PayPal API, jQuery, Twilio API, Redux-Saga, PhantomJS, Puppeteer, REST APIs, Venmo API, Google APIs, Doctrine, NumPy, Scikit-learn, Pandas, TensorFlow, Keras, Stripe Connect
Tools
Stripe Checkout, Webpack, Claude Code, PyCharm, WebStorm, Apache Tomcat, Jira, Kafka Streams, Google Cloud Console, Git, GitLab, GitLab CI/CD, Sentry, Ansible, Confluence, Redux Thunk, Docker Compose, Vagrant, VirtualBox, Composer, Jenkins, Stripe Express
Languages
Python, JavaScript, PHP, PHP 7, HTML, CSS, GraphQL, TypeScript, Java, Go, SQL
Frameworks
Symfony, Django, Redux, Jest, Cypress, Spring Boot, Flask, React Native, Spring, Android SDK, Symfony 4, Symfony 2, Symfony 3, Bootstrap, AngularJS, Laravel, Ionic 2, CodeIgniter, Angular, Next.js, Swagger, LangGraph
Platforms
Docker, Amazon Web Services (AWS), Amazon EC2, Linux, AWS Lambda, MacOS, Apache Kafka, Android, Blockchain, Kubernetes, New Relic, HubSpot, Contentful, CrewAI
Storage
Relational Databases, PostgreSQL, MySQL, Amazon DynamoDB, MongoDB, Elasticsearch
Paradigms
Object-oriented Programming (OOP), Agile, Continuous Integration (CI), Continuous Development (CD), Unit Testing, Design Patterns
Other
Data Structures, Full-stack, Architecture, APIs, Authentication, Serverless, Artificial Intelligence (AI), Algorithms, System Design, Operating Systems, In-app Purchases, Google In-app Billing, Subscription Processing, eCommerce, Browser Automation, Remote Team Leadership, Containers, Infrastructure as Code (IaC), Payment APIs, BrainTree, PayPal, Klarna, Amazon RDS, Vertex, Metabase, Apple Pay, Single Sign-on (SSO), Layer0, Code Review, Machine Learning, Deep Learning, Neural Networks, LLM Application, Vector Databases, Responsible AI, Prompt Engineering, AI Orchestation, Retrieval-augmented Generation (RAG), LangChain, Agentic AI, BeeAI, Stripe Terminal, Stripe Payments, Stripe Marketplace
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