# 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): Built an LLM evaluation and prompt-management platform with versioned prompt promotion, automated quality scoring, provider-agnostic AI integrations, async job processing, and PII-redacted observability—adding pre-release output gates and end-to-end incident visibility. Hardened secrets management across 5+ backend microservices by separating credentials into a dedicated secrets manager and general configuration into a parameter store; completed the zero-downtime migration and reduced the impact scope of credential-store misconfiguration or exposure.
- **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**: Git, MacOS, Render, Kubernetes, Heroku, Supabase, Docker, Amazon Web Services, TailwindCSS, GNU Bash, VS Code, ZSH, Google Cloud, Linux, Neovim, Netlify, Digital Ocean, FlyIO, Elasticsearch
- **programming language**: Purescript, Haskell, JavaScript, TypeScript
- **framework and runtime**: NestJS, NodeJS, NextJs, Bun, Express
- **databases**: Redis, MySQL, PostgreSQL, CouchDB, MongoDB
- **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
- [Use grill-me to Pressure-Test an AI Implementation Plan Before Code](https://www.shubhkumar.in/blogs/grill-me-ai-skill-pressure-test-implementation-plans): A detailed guide to using grill-me to challenge architecture and product decisions before an AI coding agent starts implementation.
- [Four AI Agent Skills That Make Coding Workflows Sharper](https://www.shubhkumar.in/blogs/four-ai-agent-skills-caveman-superpowers-grill-me-handoff): A practical 10-minute guide to using Caveman, Superpowers, grill-me, and handoff at the right stages of an AI-assisted engineering workflow.
- [The Golden Rule of Payout Systems: Why "Pending" is Never a Failure](https://www.shubhkumar.in/blogs/the-golden-rule-of-payout-systems-why-pending-is-never-a-failure): Why Pending is the safest state in payment systems. Transaction uncertainty as failure causes duplicate payments. Conservative state machines beat.
- [Type-Driven Security: Reducing OWASP Risk With Strong Types](https://www.shubhkumar.in/blogs/type-driven-security-how-strong-type-systems-eliminate-top-owasp-vulnerabilities): How strong types can reduce common OWASP risks through DTOs, branded IDs, parameterized SQL, safe HTML handling, and runtime validation.
- [Architecture from Day One: The Practical Guide to Scalable Backend Systems](https://www.shubhkumar.in/blogs/mastering-scalable-backend-systems): Building scalable backend systems: stateless design, caching, database sharding, CAP theorem, load balancing, EDA, and production performance patterns.
- [How I Built a Personal AI Assistant That Lives in Telegram](https://www.shubhkumar.in/blogs/building-a-telegram-ai-agent-for-personal-use): A practical engineering guide to building a secure Telegram AI assistant with Bun, Telegraf, OpenAI, Composio, SQLite, scheduling, and observability.
- [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): Deep dive into building my personal site with Next.js, Bun, Fly.io, and MongoDB—covering caching, CI/CD, security, SEO, performance, testing, and cost.
- [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): A workflow latency case study: removing polling and queue wait enabled the fast path; FP helped make async orchestration explicit and reliable.
- [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): A practical engineering guide to resilient in-flight sync: state machines, manifests, retries, security, observability, rollback, and fault testing.
- [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): Authorized security practice sharpens system design through provenance, authorization, least privilege, threat modeling, observability, and safe testing.
- [Demystifying the Trinity: Functor, Applicative, and Monad in PureScript](https://www.shubhkumar.in/blogs/demystifying-the-trinity-functor-applicative-and-monad-in-purescript): Learn Functor, Applicative, and Monad in PureScript with precise Maybe and Either examples, do notation, and practical guidance.
- [AI Is Making Senior Engineers 10x Faster - And 10x More Exhausted](https://www.shubhkumar.in/blogs/ai-senior-engineer-thought): AI speeds up senior engineers, but it also shifts more validation, review, and decision-making onto them. Practical ways to protect quality and energy.