Shirshendu Bhowmick, Developer in Bengaluru, Karnataka, India
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Shirshendu Bhowmick

Bio

Shirshendu is a senior full-stack engineer with 9+ years of experience building high-scale solutions for fintech and travel tech. He architects resilient back ends (Go, Node.js) handling over one million daily requests and optimized front ends (React, Next.js) for over two million monthly users. Recently, he engineered a full-stack generative AI solution that cut manual effort by 40%. He excels in building secure, scalable applications from scratch, with deep expertise in AWS and system design.

Portfolio

Bird (formerly MessageBird)
Go, JavaScript, TypeScript, Node.js, React, Tailwind CSS, Tailwind UI...
Marcato Partners
React, Server-side Rendering (SSR), Client-side JavaScript Frameworks, Remix...
smallcase
JavaScript, Go, Node.js, React, Next.js, Webpack, MongoDB, Express.js...

Experience

  • JavaScript - 8 years
  • Node.js - 8 years
  • React - 6 years
  • Go - 5 years
  • Next.js - 5 years
  • Large Language Models (LLMs) - 2 years
  • Generative Artificial Intelligence (GenAI) - 2 years
  • Artificial Intelligence (AI) - 2 years

Preferred Environment

Git, Node.js, Go, JavaScript, Next.js, React, SQL, NoSQL, Artificial Intelligence (AI), Generative Artificial Intelligence (GenAI)

The most amazing...

...impact I've delivered, from scaling a fintech app to 2+ million monthly users to building a GenAI tool that cut a team's manual workload by 40%.

Work Experience

Senior Software Engineer

2024 - 2025
Bird (formerly MessageBird)
  • Built distributed Go billing microservices (200,000+ daily requests) using gRPC and REST APIs. Architected fault-tolerant subscription and usage metering systems, enabling accurate customer tracking and driving revenue growth.
  • Developed a scalable notification microservice, handling high-volume asynchronous alerts (1,000+ daily) through email and push channels using SparkPost and Firebase, achieving a 99.7% delivery rate (measured over a period of three months).
  • Led strategic migration of an internal operations platform from Retool to a distributed microservices architecture, transforming it into a revenue-generating SaaS product while reducing operational costs by eliminating third-party dependencies.
  • Leveraged extensive React and front-end expertise alongside primary Go responsibilities to deliver full-stack solutions, including critical bug fixes and feature enhancements, ensuring seamless product development during team bandwidth constraints.
Technologies: Go, JavaScript, TypeScript, Node.js, React, Tailwind CSS, Tailwind UI, Amazon DynamoDB, PostgreSQL, PostgREST, gRPC, REST, CI/CD Pipelines, MacOS, Visual Studio Code (VS Code)

Senior Developer

2022 - 2024
Marcato Partners
  • Led the strategic migration of a React SPA to a Remix SSR application. This improved SEO by eliminating search console errors and significantly boosted user experience, achieving all-green Lighthouse performance metrics.
  • Engineered a scalable service using React PDF to automate the generation of critical business documents like invoices and legal agreements, streamlining core operational workflows and reducing manual effort.
  • Engineered a versatile email generation service that abstracted the provider layer. This allowed the company to dynamically switch between vendors for strategic A/B testing and significant operational cost savings.
  • Architected key user-facing features, from a complex tax system to an advanced Mapbox UI. Also built an OCR service using AWS Textract to automate data extraction from US driver's licenses.
  • Proactively managed the health of the technology stack by leading framework and library upgrades. Drove initiatives to migrate legacy code to modern alternatives, reducing technical debt and improving maintainability.
  • Engineered the analytics infrastructure with Mixpanel and Google Analytics to track key performance indicators (KPIs), providing critical data on feature adoption and user engagement to guide product strategy.
  • Engineered a robust image optimization pipeline for user-uploaded content. This automated responsive resizing and implementation of lazy loading significantly improved page load speeds and visual consistency across all devices.
  • Engineered a multi-channel notification system for transactional communications. Utilised Twilio for SMS/email delivery and Mailtrap for safe testing, ensuring users received timely and reliable order and event updates.
  • Drove a 30% improvement in application load times by architecting and implementing strategic CDN and browser cache policies. This initiative also significantly reduced monthly CDN operational costs for the business.
  • Ensured a seamless user experience by diagnosing and fixing critical React 18 hydration and SSR issues. Implemented Sentry to establish a robust error monitoring pipeline for rapid bug detection and resolution.
Technologies: React, Server-side Rendering (SSR), Client-side JavaScript Frameworks, Remix, MySQL, Node.js, API Integration, Payment Gateways, Docker, Playwright, Responsive Web Design (RWD), Software Architecture, API Design, Responsive UI, Styled-components, Material UI, RESTFul APIs, Identity & Access Management (IAM), Back-end Development, Grafana, Datadog, Front-end Development, Automated Testing, Amazon S3 (AWS S3), Drizzle, React Query, Tailwind UI, MacOS, Visual Studio Code (VS Code)

Senior Software Engineer

2020 - 2024
smallcase
  • Joined the company in 2018 as a front-end engineer and later moved to a full-stack role.
  • Set up projects on the front and back end from scratch, using React, Webpack, Next.js, TypeScript, Node.js, and Go. Developed consumer-facing CSR and SSR front-end applications using React and Next.js.
  • Built a multitenant application in React to improve maintainability, developer experience, and application bundle size.
  • Created back-end libraries and microservices to create application APIs and bridge services, REST, and gRPC to communicate with external APIs and services for equity stock-order placement and management.
  • Contributed towards component and service design patterns, improving code reusability, architecture, and performance improvements.
  • Worked on optimizing cache policy on CDN and browser level, optimizing UX, using PWA, and making security improvements to prevent attacks like CSRF and XSS.
  • Set up error tracking and logging using Sentry and an ELK stack. Developed a Jest and React Testing Library and improved test coverage. Built an in-house Webpack loader and plugin to automate test ID generation used in automated end-to-end testing.
  • Created a payment service that integrates with different gateways to support payments via card, UPI, bank transfer (one-time and recurring), etc. It enables payments for various other company internal services.
  • Developed a generative AI-based assistive tool (uses LLM like OpenAI, Calude, etc.) for the CX team, which is a combination of a Chrome extension and a back-end service. The initial version resulted in a 40% reduction in human efforts.
Technologies: JavaScript, Go, Node.js, React, Next.js, Webpack, MongoDB, Express.js, Storybook, Server-side Rendering (SSR), Babel, CI/CD Pipelines, PostgreSQL, APIs, REST, Redux, Amazon Web Services (AWS), gRPC, Front-end, HTML, System Architecture, Architecture, WebSockets, HTML5, Full-stack, Full-stack Development, Unit Testing, Integration Testing, REST APIs, Serverless, Serverless Architecture, Monorepos, Back-end, CSS, CSS3, Microservices, Microservices Architecture, Jenkins, AWS Lambda, PWA, Progressive Web Applications (PWAs), Redis, Redis Cache, JSON Web Tokens (JWT), Multitenancy, User Interface (UI), User Experience (UX), Design, Apache Kafka, Lerna, MERN Stack, Test-driven Development (TDD), React Redux, OAuth 2, OAuth, GraphQL, NPM, Client-side JavaScript Frameworks, API Integration, Payment Gateways, Fintech, NestJS, LangChain, OpenAI, Large Language Models (LLMs), Docker, Artificial Intelligence (AI), Retrieval-augmented Generation (RAG), Vector Databases, Cryptography, Chatbots, Supabase, FastAPI, Responsive Web Design (RWD), AI Chatbots, Software Architecture, API Design, Responsive UI, GitHub Copilot Chat, RESTFul APIs, Gin Tonic, Identity & Access Management (IAM), Highcharts, Open-source LLMs, Back-end Development, Chrome Extensions, OpenAI API, Futures & Options, Automated Trading Software, Stock Trading, Trading, React Hook Form, React Testing Library, Grafana, Jest, Argo CD, Front-end Development, Axios, Automated Testing, Amazon S3 (AWS S3), Drizzle, Tailwind UI, MacOS, Visual Studio Code (VS Code)

Front-end Software Engineer

2018 - 2020
smallcase
  • Developed consumer-facing CSR and SSR front-end applications using React and Next.js. General users use the apps to simplify their financial investments.
  • Built various product features and UIs from design. Examples like search functionality, SIP orders for equities, and setting up architecture for role-based product features will be implemented.
  • Developed landing and marketing pages in React and Next.js. Also, ported legacy landing pages built with jQuery to a modern React stack.
  • Set up other projects on the front and back end from scratch using React, Redux, Webpack, Next.js, and TypeScript.
  • Contributed towards building an internal design system and a component library.
  • Contributed to improving the application's performance by reducing bundle size, optimizing critical rendering path, and avoiding unnecessary JavaScript execution.
Technologies: Amazon Web Services (AWS), React, Next.js, Redux, Git, Server-side Rendering (SSR), JavaScript, Node.js, HTML5, CSS, Front-end, REST, APIs, Multitenancy, Lerna, Monorepos, OAuth 2, OAuth, NPM, Client-side JavaScript Frameworks, API Integration, Fintech, Docker, Responsive Web Design (RWD), Software Architecture, API Design, Responsive UI, RESTFul APIs, Identity & Access Management (IAM), Highcharts, Back-end Development, Automated Trading Software, Stock Trading, Trading, React Testing Library, Grafana, Jest, Front-end Development, Axios, Automated Testing, Amazon S3 (AWS S3), Drizzle, Tailwind UI, MacOS, Visual Studio Code (VS Code)

Programmer Analyst

2016 - 2018
Cognizant
  • Worked on developing an internal robotic process-automation tool to automate periodic and manual tasks involved in a production support project. Achieved around 50% reduction in the human effort post-production implementation.
  • Built the front end with JavaScript and CSS and the back end with Python and MongoDB.
  • Developed a drag-and-drop UI dashboard containing reports and charts using a JavaScript-based library.
Technologies: JavaScript, CSS, MongoDB, Python, REST, APIs, HTML, Front-end, System Architecture, Architecture, HTML5, Full-stack, Full-stack Development, REST APIs, Unit Testing, Microservices, Microservices Architecture, JSON Web Tokens (JWT), Multitenancy, User Interface (UI), User Experience (UX), MERN Stack, NPM, Client-side JavaScript Frameworks, API Integration, Responsive Web Design (RWD), Software Architecture, Responsive UI, RESTFul APIs, Back-end Development, Front-end Development, Visual Studio Code (VS Code)

Freelance Web Developer

2012 - 2016
Freelance
  • Built multiple full-stack applications for eCommerce and logistics companies. The applications are the back office and admin panel with role-based access control and data visualizations.
  • Developed multiple landing and marketing pages for SME companies trying to establish their presence in the online market.
  • Created applications that integrated with existing production MySQL databases to fetch data and generate various reports, and audit logs.
Technologies: JavaScript, jQuery, HTML, CSS, PHP, MySQL, Node.js, Bootstrap, Client-side JavaScript Frameworks, API Integration, Responsive Web Design (RWD), Software Architecture, Responsive UI, RESTFul APIs, Back-end Development, MacOS, Visual Studio Code (VS Code)

Experience

Chat Application

https://github.com/shirshendubhowmick/chat-app-server
This is a room-based chat application built with TypeScript, React, Node.js, and Socket.io.

The main idea behind this is to demonstrate how to build a chat UI, render chat messages correctly, and handle real-time communications.

Multitenant SaaS Application with React

https://www.smallcase.com/
Developed an application offered as a SaaS and to end-users as in the B2B2C model. The app primarily helps users with simplified investment options in equity stocks. It is a one-stop solution for purchasing, managing, rebalancing, and engaging in a stock portfolio SIP.

Tech stack:
• Single codebase with adapter pattern for multitenancy.
• Front end build system with Webpack.
• Multiple microservices were written with Node.js and Go to handle back-end functionalities like application API, order management, and communication with brokers, using external broker APIs.

Maintaining React Aria MenuButton Project

https://github.com/davidtheclark/react-aria-menubutton
This is a popular open-source dropdown comment built with React. I am actively maintaining this project, primarily taking care of the following things:

• Bug fixes.
• Investigating issues raised by the users.
• Feature improvements.
• Version upgrades.
• CI/CD for tests and build.
• Various codebase improvements.

Personal Website

http://www.shirshendu.dev
This is a personal portfolio website that was completely self-designed and developed. The design was created using Figma, and it was developed with React and Gatsby. It is currently hosted on Firebase.

Travel Tech Marketplace

An application to book adventurous ride experiences with ATVs, snowmobiles, etc. This is a server-side rendered application built with React and RemixJS

This is part of a suite of products that includes other applications for the seller and admin side.

Education

2012 - 2016

Bachelor's Degree in Electronics and Instrumentation Engineering

West Bengal University of Technology - West Bengal, India

Certifications

APRIL 2016 - PRESENT

Machine Learning

Stanford University

Skills

Libraries/APIs

Node.js, React, Socket.IO, REST APIs, Redis Queue, React Redux, OpenAI API, React Hook Form, React Testing Library, Drizzle, React Query, Playwright, Highcharts, jQuery, PostgREST

Tools

Git, Webpack, NPM, Grafana, Jenkins, Babel, Lerna

Languages

Go, JavaScript, CSS, TypeScript, Python, HTML, HTML5, CSS3, SQL, GraphQL, PHP

Frameworks

Next.js, Express.js, gRPC, Redux, JSON Web Tokens (JWT), OAuth 2, NestJS, Material UI, Jest, Tailwind CSS, Bootstrap, Remix

Paradigms

REST, Unit Testing, Serverless Architecture, Microservices, Microservices Architecture, Test-driven Development (TDD), Responsive Web Design (RWD), Automated Testing

Platforms

MacOS, Amazon Web Services (AWS), AWS Lambda, Visual Studio Code (VS Code), Vercel, Docker, Google Cloud Platform (GCP), Apache Kafka, Firebase

Storage

Redis, Redis Cache, Datadog, Amazon S3 (AWS S3), MongoDB, PostgreSQL, NoSQL, MySQL, Amazon DynamoDB

Other

Storybook, Server-side Rendering (SSR), CI/CD Pipelines, APIs, Front-end, System Architecture, Architecture, WebSockets, Full-stack, Full-stack Development, Integration Testing, Serverless, Monorepos, Back-end, PWA, Progressive Web Applications (PWAs), Multitenancy, User Interface (UI), User Experience (UX), Design, MERN Stack, OAuth, Client-side JavaScript Frameworks, API Integration, Payment Gateways, Fintech, OpenAI, Cryptography, Software Architecture, API Design, Responsive UI, Styled-components, GitHub Copilot Chat, RESTFul APIs, Gin Tonic, Identity & Access Management (IAM), Back-end Development, Chrome Extensions, Automated Trading Software, Stock Trading, Trading, Argo CD, Front-end Development, Axios, Tailwind UI, LangChain, Large Language Models (LLMs), Artificial Intelligence (AI), Retrieval-augmented Generation (RAG), Vector Databases, Chatbots, Supabase, FastAPI, AI Chatbots, Open-source LLMs, Futures & Options, Generative Artificial Intelligence (GenAI), Machine Learning, Gatsby, Engineering, Vite

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