# Shubham Kumar
> Senior Engineer II with 8+ years of experience building scalable, high-availability backend systems across fintech and aviation domains. Specialized in cloud-native architecture, distributed systems, and microservices using Node.js, TypeScript, Haskell, and PureScript. Proven track record of optimizing system performance, reducing latency by up to 90%, and architecting mission-critical infrastructure serving millions of users.

## About
Senior Engineer II

## Sections
- [Home](https://www.shubhkumar.in): Portfolio landing page with hero, about, experience, skills, services, testimonials, certificates, and contact
- [Blog](https://www.shubhkumar.in/blogs): Technical articles on backend engineering, system design, and building at scale
- [Dashboard](https://www.shubhkumar.in/dashboard): Workout tracker, social metrics, and blog analytics
- [Health](https://www.shubhkumar.in/health): Workout session tracker with calendar, streaks, and stats
- [Consulting](https://www.shubhkumar.in/consulting): Booking page for consulting sessions

## Experience
- **Senior Engineer II** at Alaan (2026–Present): Designing System 
- **Associate Lead Engineer** at AirFi (2025–2026): Architected mission-critical LEO (Low Earth Orbit) connectivity system, collaborating across
cross-functional teams to design scalable architecture enabling real-time, high-speed in-flight
internet Spearheaded "Next Gen" hardware bring-up, modernizing software stack while preserving core system philosophies to ensure backward compatibility and future-proof performance
- **Senior Software Engineer** at AirFi (2021–2025): Engineered high-availability backend services using Node.js and TypeScript, increasing captive portal launch success rates from 50% to over 75% for global airline passengers Optimized ADS-B event communication and satellite email accessibility, ensuring reliable data synchronization for offline-first embedded systems in low-connectivity environments  Architected versatile remote sync service that streamlined content distribution across diverse aircraft platforms, significantly reducing manual deployment overhead Enhanced offline payment applications by integrating online verification capabilities when internet connectivity is available Improved email accessibility via satellite, playing pivotal role in project success
- **Software Developer** at Juspay (2018–2021): Revamped CRED payment backend using PureScript and Haskell, achieving 90% reduction in payout latency by slashing processing time from 60 seconds to 6 seconds Enabled seamless credit card transactions by refactoring transaction flows and reducing processing time at all stages Implemented generic fulfillment system for various financial operations, ensuring streamlined and efficient processing Integrated complex multi-bank payout providers and Bill Payment services (HP Gas) for GooglePay, enabling seamless transaction flows for millions of active users

## Skills
- **tools**: Render, Kubernetes, Linux, Digital Ocean, FlyIO, Supabase, GNU Bash, ZSH, MacOS, Heroku, VS Code, Docker, TailwindCSS, Netlify, Neovim, Amazon Web Services, Google Cloud, Elasticsearch, Git
- **framework and runtime**: NestJS, Express, NextJs, NodeJS, Bun
- **programming language**: Purescript, TypeScript, JavaScript, Haskell
- **databases**: Redis, MySQL, CouchDB, MongoDB, PostgreSQL
- **Specializations**: Distributed Systems, High-Availability Architecture, Latency Optimization, Embedded Systems

## Services
- **Software System Design & Optimization**: Experienced in building and improving complex software systems to enhance performance and reliability.
- **Payment Systems & Fintech Solutions**: Skilled in developing fast, secure payment backends and integrating with banks and payment providers.
- **Side Projects & Open Source**: Creator of various tech tools and bots, contributing to open-source and automation projects.

## Blog Posts
- [How I Built a Personal AI Assistant That Lives in Telegram](https://www.shubhkumar.in/blogs/building-a-telegram-ai-agent-for-personal-use): Build a personal AI agent in Telegram using Bun, Telegraf, SQLite, and Composio. Zero-infrastructure with conversation memory and prompt-injection defenses.
- [What's All Am I Hosting? — Full Infrastructure Breakdown](https://www.shubhkumar.in/blogs/whats-all-am-i-hosting): How I run my entire online presence — main site, APIs, email, monitoring, URL shortener — for $0/month using free tiers and self-hosted infrastructure.
- [Building My Personal Website From Scratch: Tech Stack, Architecture, and Lessons Learned](https://www.shubhkumar.in/blogs/building-my-personal-website-from-scratch-tech-stack-architecture-and-lessons-learned): Building a personal website from scratch: tech stack, architecture trade-offs, deployment pipeline, and lessons on performance, SEO, and DX.
- [Moving from 60s to 6s: Latency Optimization Lessons from Functional Programming](https://www.shubhkumar.in/blogs/moving-from-60s-to-6s-latency-optimization-lessons-from-functional-programming): How functional programming enabled 10x latency reduction (60s→6s). Referential transparency for caching, algebraic types for errors, concurrency.
- [The Disconnected Edge: How We Solved In-Flight Data Sync at 35,000 Feet](https://www.shubhkumar.in/blogs/the-disconnected-edge-how-we-solved-in-flight-data-sync-at-35000-feet): In-flight data sync at 35,000 feet. Offline-first architecture, CRDT conflict resolution, bandwidth constraints, and systems with no connectivity.
- [Turning Your AI Into an Adversarial Security Agent: The SKILLS.md Framework](https://www.shubhkumar.in/blogs/turning-your-ai-into-an-adversarial-security-agent-the-skillsmd-framework): Using SKILLS.md to turn AI assistants into adversarial security agents. Prompt-based auditing, automated threat modeling, vulnerability discovery.
- [Breaking to Build: How CTF and Bug Bounty Hunting Rewires System Design](https://www.shubhkumar.in/blogs/breaking-to-build-how-ctf-and-bug-bounty-hunting-rewires-system-design): How CTF and bug bounty hunting develop system design intuition. Adversarial thinking, attack surface awareness, breaking things to build better.
- [Demystifying the Trinity: Functor, Applicative, and Monad in PureScript](https://www.shubhkumar.in/blogs/demystifying-the-trinity-functor-applicative-and-monad-in-purescript): Practical Functor, Applicative, and Monad in PureScript. Real-world patterns over abstract math — type classes solving concrete problems.
- [AI Is Making Senior Engineers 10x Faster - And 10x More Exhausted](https://www.shubhkumar.in/blogs/ai-senior-engineer-thought): AI tools make senior engineers 10x faster — and 10x more exhausted. Productivity vs cognitive load, validating AI output, senior judgment.