Ragib Ahsan
Verified Expert in Engineering
Back-end Developer
Bangkok, Thailand
Toptal member since April 29, 2015
Ragib is a results-oriented software engineer with 9+ years of experience building scalable and AI-powered solutions on cloud-native platforms while leading small teams with full ownership. He specializes in back-end engineering and has delivered business-critical full-stack systems using well-architected code, microservices, Python and JavaScript frameworks, modern databases, CI/CD, and observability tooling. Ragib values fast delivery, maintainable code, and mentoring teams across the SDLC.
Portfolio
Experience
- Django - 8 years
- Back-end - 8 years
- Microservices - 6 years
- CI/CD Pipelines - 5 years
- Amazon Web Services (AWS) - 5 years
- React - 5 years
- FastAPI - 5 years
- AI Integration - 2 years
Preferred Environment
MacOS, Python, Back-end, Amazon Web Services (AWS)
The most amazing...
...project I've worked on is an automation platform that can provide a personalized job search experience, supporting dynamic UI configuration without coding.
Work Experience
Lead Software Engineer
Nymph Solutions
- Designed and delivered a full-stack job-search automation platform that captures user interactions, integrates with external APIs, and automates multi-step workflows to define the user journey.
- Led scrum teams across multiple projects, improving velocity and team efficiency through strategic hiring, mentoring, well-architected project scaffolding, and automation across the SDLC.
- Designed and deployed a retrieval-augmented generation (RAG) system leveraging multiple LLMs, vector search, and prompting to generate context-aware, personalized cover letters from job descriptions.
- Led the back-end optimization of a bank’s MFS service, guiding the migration of core Python services to Go and gRPC, improving P99 latency from 3.4s to 50ms, and implementing feature flags for safe, zero-downtime rollout.
- Led migration of legacy PostgreSQL and MongoDB systems to cloud architectures, ensuring data integrity, seamless integration, and effective client communication.
- Developed an intelligent Receipt Scanner system using OCR and OpenAI API for high-accuracy receipt data extraction, automated expense recording, and personalized spending insights.
Senior Full-stack/JavaScript Engineer
My Project Pal, LLC
- Built an AI-driven home remodeling review platform that analyzed homeowner-submitted photos and notes across construction phases and generated structured, actionable feedback using Next.js, Node.js, PostgreSQL, and OpenAI APIs.
- Integrated Stripe-based payment and credit workflows to support paid reviews, including checkout handling, project-linked credit tracking, and reliable payment confirmation flows.
- Designed review workflows and underlying data models for users, projects, submissions, and review history, improving platform structure, traceability, and long-term maintainability.
Full-stack Software Engineer
Booking Holdings
- Contributed across the software development lifecycle to design and implement a no-code workflow generation system with Scala for a high-performance back end and React for a modular, component-driven front end.
- Designed and led the implementation of a group-based authorization system for a business-critical internal tool, enhancing security, remediating unauthorized access, and adding traceability.
- Resolved critical production flaws, recovering $650,000, and optimized workflows through GPT and LLM, resulting in a global handling time reduction of 1.7% and an annual cost-saving of $5 million.
- Migrated CI/CD pipelines from TeamCity to GitLab and implemented standardized pipelines for all team projects, ensuring compliance with company-wide best practices.
- Collaborated with cross-functional teams, including product, design, and sales, to translate business requirements into actionable plans.
Software Engineer
Various Clients
- Led an agile team of four to restructure CommChat’s REST API for 10,000 users, delivering a backward-compatible, scalable version while adapting to rapid changes.
- Developed a library that periodically aggregates and ships logs to Elasticsearch using Redis as a buffer.
- Integrated several external services with the core fintech system. Communicated with stakeholders and resolved issues.
- Implemented scripts and APIs for data synchronization and a dashboard for a mobile banking application. Monitored scheduled tasks.
- Led development of an online hire agreement system for Butterfly Marketing Limited, used by thousands of merchants and internal users, from inception to handover.
- Designed and implemented APIs for a news and media content aggregator service in a startup.
- Implemented the VoIP module supporting chatrooms with Twilio.
- Built an Automatic Number Plate Recognition (ANPR) API with Python, OpenCV, and YOLOv8, applying machine learning for robust license plate detection in a digital parking system.
Co-founder & Software Engineer
Appinoid, Ltd.
- Developed a variant of a popular puzzle game on the Facebook web platform.
- Developed an infinite run 2D game on the Unity Android platform.
- Developed an Instagram-like grabber iOS app with the Parse Cloud platform.
- Developed a gift card distribution iOS app with the Parse Cloud platform.
- Gained valuable experience in project management, requirement analysis, and documentation.
Experience
No-code Workflow Generator
The platform empowered non-technical staff to build business-critical customer service workflows, featuring group-based access control and end-to-end observability for full execution visibility.
Example: Product owners could define booking-cancellation workflows, which customer service agents then followed step by step to resolve customer complaints consistently and efficiently.
Job Board Automation Tool
Example: Product owners can create and store multiple user experience flows driven by dynamic data and user input, composed of various UI components. End users then navigate these predefined experiences, which can be modified or reconfigured at runtime without requiring redeployment or changes to the application code.
Receipt Scanner System
The system features a React-based front end for seamless uploads and review, a FastAPI back end for high-throughput processing, and PostgreSQL for reliable data storage. Deployed on AWS with GitHub Actions CI/CD, the solution is designed for automation of end-to-end expense workflows.
Skills
Libraries/APIs
React, OpenAI API, Node.js, Stripe, WhatsApp API, REST APIs, API Development, Shopify API, Django ORM, Pydantic, Stripe API, Stripe Connect, Auth, Google APIs, Google Workspace APIs, Vue, Vue 3, Three.js, WebGL, Twilio API, Google Maps, Asyncio, Typeform, Google Maps API
Tools
Git, Pytest, Claude, Windsurf, Amazon Textract, Firebase Cloud Messaging (FCM), n8n, Zapier, Amazon Simple Queue Service (SQS), NGINX, RabbitMQ, GitHub, Claude Code, Sentry, Google Sheets, Stripe Checkout, AI SDK, Celery, Shadcn, ChatGPT, Microsoft Excel, PyCharm, PgBouncer, GitLab CI/CD, Jira, GIS, BigQuery, Amazon Cognito, AWS CloudFormation, Terraform, Webpack, Expo, Microsoft Teams, Codex, AWS Fargate, AWS Cloud Development Kit (CDK), Retool, Asana, Grafana, Confluence, Xero
Languages
Python, Java, JavaScript, TypeScript, SQL, Go, VB.NET, PHP, HTML, GraphQL, CSS, C++, Forth, Perl, Scala
Frameworks
Django, Flask, LangGraph, Jest, Next.js, OAuth 2, Spring Boot, JSON Web Tokens (JWT), React Native, gRPC, .NET, Symfony, Serverless Framework, Redux, Express.js, Laravel, Selenium, Spring, Tailwind CSS, NestJS, Play Framework, Koa, AngularJS, Angular, Starlette
Paradigms
Code Refactoring, Agile, Agile Software Development, Role-based Access Control (RBAC), Automation, Test-driven Development (TDD), Event-driven Architecture, REST, API Architecture, Scrum, Microservices, Model Context Protocol (MCP), ETL, DevOps, Microservices Architecture, HIPAA Compliance, B2C, Mobile Development, Automated Testing, Unit Testing, Real-time Systems, OLAP
Platforms
Amazon Web Services (AWS), AWS Lambda, Django CMS, Vercel, Linux, DigitalOcean, Algolia, MacOS, Docker, Apache Kafka, Google Cloud Platform (GCP), Kubernetes, Azure, Airbyte, Directus, HubSpot, iOS, Twilio, Ubuntu, Firebase, GoHighLevel, Replit, ClickFunnels, Amazon EC2, Android, Zoho CRM
Storage
PostgreSQL, MongoDB, Amazon S3 (AWS S3), JSON, Relational Databases, Data Integration, Databases, NoSQL, Microsoft SQL Server, MySQL, Redis, Elasticsearch, Neo4j, Amazon DynamoDB, PostGIS, Data Pipelines, ClickHouse
Industry Expertise
Project Management, Cybersecurity, Healthcare
Other
FastAPI, Optical Character Recognition (OCR), GitHub Actions, Back-end, Artificial Intelligence (AI), LangChain, Full-stack Development, Back-end Development, APIs, Full-stack, Large Language Models (LLMs), API Integration, Web Development, AI Tools, Gemini, Tesseract, Web Scraping, Agentic AI, Code Deployment, Supabase, Application State Management, RESTFul APIs, Software Architecture, OAuth, RESTful Microservices, Front-end Development, Vibe Coding, OpenAI, Prompt Engineering, Relational Database Design, Cross-platform App Development, Stripe Payments, API Design, Debugging, Webhooks, Business Requirements, Business Requirements Documentation (BRD), Workflow Automation, Technical Documentation, Authentication, Single Sign-on (SSO), Security, Non-relational Databases, Cursor AI, Supabase Auth, Business Process Automation, Database Normalization, Database Schema Design, Large-scale Projects, Web Security, Team Leadership, AI Agents, Website Data Scraping, General Data Protection Regulation (GDPR), Generative Artificial Intelligence (GenAI), Workflow, Workflow Automation & System Integration, AI Chatbots, System Architecture, Dashboards, AI Automation, Dashboard Development, Algorithms, Linux Servers, Payment APIs, ACH Payments, Leadership, Perplexity, End-to-end Implementation (E2E), Minimum Viable Product (MVP), AI Programming, AI-generated Code, Integration, Compliance, Coding, Airtable, Cloud Infrastructure, Data Migration, Magic Link, Automations, Third-party APIs, Third-party Integration, RAG Systems, Real-time Data, AI-assisted Development, Payment Gateways, User Roles, Payments, Communication, Chrome Extensions, Mobile Wallet, HTTP, Middleware, Back-end Performance, Loveable, Email Automation, Event-driven Systems, CI/CD Pipelines, AI Integration, Distributed Systems, Retrieval-augmented Generation (RAG), Computer Vision, PDF, Gemini API, Fintech, Technical Leadership, Browser Automation, Data Scraping, Scraping, Geospatial Data, Cloud Architecture, Software as a Service (SaaS), Image Processing, Architecture, Data Analysis, Dagster, PDF Scraping, Classification, Conversational Agent, Mobile App Development, CTO, Solution Architecture, Anthropic, Healthcare Software, HIPAA, Healthcare IT, Microsoft 365, Front-end, Audio, Deployment, SaaS, UI Development, Cloud, Bots, ETL Pipelines, Database Optimization, Query Optimization, Pixel Perfect, Amazon Bedrock, Large Data Sets, Mentorship, User Experience (UX), User Interface (UI), Infrastructure, Geometric Modeling, AI Voice Agents, CRM, Analytics, Data Engineering, Machine Learning, Product Engineering, Infrastructure as a Service (IaaS), GitHub Codespaces, Open-source LLMs, GeoJSON, OpenStreetMap, Customer Relationship Management (CRM), Data Management, Marketplaces, Technical Architecture, Computer Science, Message Queues, Queuing Systems, Scheduling, Task Scheduling, TypeORM, Responsive Design, API Gateways, PayPal, GPS, Tailwind UI, GDPR, Software as a Medical Device (SaMD), Internet of Things (IoT), QR Codes, Web Extensions, Code Auditing, RAG Architecture, App Support, Bug Triage, Row-level Security (RLS), Data Security, Product Management, Healthtech, BullMQ, Strapi, Data Processing, Wagtail CMS, Medical Software, Law, Trademarks
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