Principal Software Engineer @ Beacon.li · Hyderabad

Gulshan Kumar Singh

I turn complex ideas into fast, reliable web platforms, and lately, into AI copilots that make them smarter.

Top skills: React

8+years building
for the web

Previously atBritish TelecomEsportsXOVimaan RoboticsCredRCreditap

About

I started in 2018 as the only front-end engineer at an education-fee lending startup, shipping an Angular site, a React ERP, and my first CI/CD pipeline. At CredR I built a custom streaming SSR server that lifted Lighthouse scores from 19 to 93, and at Vimaan Robotics I proposed and built the API gateway that centralised authentication across our services.

As Tech Lead at EsportsXO I led six engineers, ran the platform on Kubernetes, and designed the bracket engine behind its tournaments. At BT I was front-end architect for broadband buy journeys, where my hybrid agent journey grew to 70% of agent orders and saved 10 to 12 minutes on each one.

Today, as Principal Engineer at Beacon.li, I build AI platform features: copilot agent loops, RAG retrieval, and ingestion that turns large files and tables into clean context. Outside product work I research cloud security, with two papers published by Springer.

IndustriesFintech, mobility, robotics, esports, telecom, and AI SaaS: 6
Springer publicationsCloud DDoS detection and cross-VM attacks: 2
Lead and architecture rolesTech Lead, front-end architect, and Principal Engineer: 3

What I do

Full-stack platforms
Web apps and APIs with React, Next.js, Node.js, and Spring Boot, from custom server-side rendering to multi-step buy journeys.
- React
- Next.js
- Node.js
- Spring Boot
AI and RAG systems
Copilot agent loops, retrieval-augmented search, and file ingestion that turns large documents and tables into clean context, using Claude, LangChain, and Qdrant.
- Claude
- LangChain
- Qdrant
Cloud and architecture
AWS, Kubernetes on EKS, and Docker, plus API gateways with central auth and video pipelines with MediaConvert.
- AWS
- Kubernetes
- Docker
- JWT

Experience

Oct 2018 – Present · 8 yrs 2 mos · Trainee Software Consultant → Principal Software Engineer

Principal Software Engineer
Beacon.liCurrent
Hyderabad, Telangana, India
May 2026 – Present7 mos
- Platform engineer on an AI platform that automates enterprise software implementations, building the platform features needed to onboard new clients and extend existing ones
- Work on the copilot chat service, whose agent loop runs tool calls and gathers the context agents need to answer users
- Fixed context overload from large uploads: files are now chunked into the RAG store, and when a user mentions a file, the 15 most relevant chunks are retrieved instead of the whole text
- Built row- and column-aware chunking for tables in the ingestion pipeline, so chunks never mix rows, columns, or empty cells
- Extended the media ingestion pipeline to detect file types and route them to extraction services, adding support for large files, more formats, image extraction, and content size limits
- Built retrieval-augmented generation with Claude models through an internal AI gateway, using LangChain and Qdrant
- Claude
- Retrieval-Augmented Generation (RAG)
- LangChain
- Qdrant
- TypeScript
- KoaJS
- Next.js
Software Engineer Specialist
British Telecom (BT)
Bengaluru, Karnataka, India
Dec 2023 – Apr 20262 yrs 5 mos
- Front-end architect in a nine-person team building Next.js buy journeys for BT broadband and wholesale products, backed by Java Spring Boot APIs and OAuth
- Built core steps of the five-step buy journey, including line selection, category selection, address validation, and checkout
- Designed a hybrid journey that lets sales agents place orders for customers in the same short web flow, replacing a long Salesforce process and saving about 10 to 12 minutes per order
- Rolled the hybrid journey out to 25% of agent orders, then expanded it to 70% after a successful launch, with agent incentives tracked automatically
- Built the agent backend in Spring Boot for managing multiple customers, tracking incentives, and overseeing orders end to end
- Changed the multi-step forms to save progress at every step instead of only at the end, so customers and agents no longer lost data and could resume later
- Migrated the journeys from Next.js 14 to Next.js 15
- Next.js
- React
- Spring Boot
- Java
Tech Lead
EsportsXO
Bengaluru, Karnataka, India
Jan 2022 – Dec 20232 yrs
- Led a team of six engineers building BattleXO, an esports community and tournament platform, owning the architecture across the web app, Koa backend, admin panel, and creator portal
- Designed the VS-mode tournament engine (about 1,600 lines) that generates single-elimination, double-elimination, and round-robin brackets for any number of teams: snake seeding, automatic byes, losers-bracket routing, grand final and third-place matches, and automatic moderator assignment
- Built the interactive bracket viewer with D3.js, featuring positioned match cards, connector lines that highlight a team's path, seed numbers, zoom, and a full-screen mode
- Top contributor to the Koa backend (MySQL with Sequelize, MongoDB, Redis caching), building tournaments, check-ins, round results, leaderboards, teams, a wallet with invoices, Google sign-in, and Firebase push notifications
- Built the Shorts video pipeline: uploads to S3, then AWS MediaConvert transcoding to H.264 MP4 with rotation handling, so clips play on any browser or phone
- Set up Kubernetes on Amazon EKS, with Docker images in ECR, Jenkins builds, and separate production, staging, and test environments with rolling deployments
- Reviewed and merged about 50 feature pull requests for the Next.js web app (team finder, team chat, Shorts, wallet, Cashfree and PhonePe payments), and sped up home-page loading
- Next.js
- KoaJS
- D3.js
- MySQL
- MongoDB
- Kubernetes
- AWS
- Docker
Earlier roles
Senior Software Developer - Fullstack · Vimaan Robotics India Pvt. Ltd.Dec 2020 – Dec 2021
Bengaluru, Karnataka, India
- Built the Angular customer dashboard for a warehouse inventory-scanning platform, showing scan results and inventory search by pallet, barcode, and storage location
- Created an interactive D3.js warehouse map of racks, aisles, and thousands of bins, colour-coded by scan status (match, mismatch, empty), with zoom, pan, and drill-down into each bin
- Proposed and built a Zuul API gateway with central JWT authentication and rate limiting in front of four Spring Boot services, replacing per-service logins that only worked together through a shared signing secret
- Added custom Java annotations for role and permission checks, so services no longer handled authentication themselves or were exposed directly
- Built a Quartz-based scheduler for automated email reports, with schedules set in configuration and recipients managed from the admin portal
- Also built a React dashboard for a second product line
- Angular
- D3.js
- Spring Boot
- Java
- Role-Based Access Control
- React
Senior Development Engineer - Fullstack · CredR - Incredible Technologies Pvt. Ltd.Aug 2019 – Nov 2020
Bengaluru, Karnataka, India
- Moved the React customer website for a used two-wheeler marketplace from client-side rendering to a custom streaming SSR server built on Express and React renderToNodeStream, covering 15 to 20 pages
- Designed per-route server data resolvers with Redux state hydration, and used loadable-components for code splitting and critical CSS extraction
- Raised the site's Lighthouse score from about 19 to 93, improving SEO and page load speed
- Hosted the SSR server on EC2 behind an Application Load Balancer with Auto Scaling, serving static assets from S3 and CloudFront with Route 53 DNS
- Rebuilt CredR Pro, the internal inventory and lead-management app, on a newer React version with a cleaner UI and Redux, and replaced its buggy login with JWT authentication and role-based access on Spring Boot
- React
- Redux
- Express.js
- Spring Boot
- AWS
- JWT
Trainee Software Consultant · Creditap Technologies Private LimitedOct 2018 – Jul 2019
Bengaluru, Karnataka, India
- Sole front-end engineer in a six-person team at an education-fee financing startup, owning the customer website and the internal ERP used by sales and operations
- Built the Angular customer site: an EMI calculator (₹5,000 to ₹3,50,000), OTP-verified loan lead capture, and a detailed school-partner onboarding form, shipped as an installable PWA
- Learned React in a week to build the lead-management ERP: filterable, paginated lead and application lists, application review, document uploads, and Excel exports
- Set up CI/CD with Bitbucket Pipelines and a custom Docker image, deploying front-end builds to S3 behind CloudFront and Route 53
- Shipped Express and MongoDB API features, including ERP login, forgot-password and change-password flows, and paginated list endpoints
- Angular
- React
- Express.js
- MongoDB
- AWS
- Docker

Experience

Selected work

Products, platforms and research I have designed and built

Open source2026 – Now

toklyn

Author and maintainer

An open-source TypeScript library for access and refresh token sessions: short-lived JWTs, refresh-token rotation with reuse detection, server-side sessions, and adapters for Express, Fastify, NestJS and Next.js.

npm packages, released together: 6
production databases supported: 5
automated tests: 375+

Rotates the refresh token on every use and revokes the whole session when a used token comes back, so a stolen token stops working for the attacker and the user alike
Made rotation one atomic store operation, so two concurrent refreshes with the same token can never both succeed, with an optional grace window for clients that refresh in parallel
Built one framework-neutral HTTP layer and thin adapters on top of it for Express, Fastify, NestJS and the Next.js App Router, in bearer or HttpOnly cookie mode
Shipped production stores for PostgreSQL, MySQL/MariaDB, SQLite, MongoDB and Redis that work with the driver or ORM an app already uses, plus a contract test suite for custom stores
Added JWKS publishing and remote verification, so other services can verify tokens with no shared secret and no session store
Secure by default: hashed refresh tokens, pinned JWT algorithms, __Host- cookies, CSRF checks on cookie writes, and Web Crypto only, so the core also runs on the Edge Runtime

TypeScript
Node.js
JWT
Next.js
Express.js
Fastify
NestJS
PostgreSQL
MySQL
SQLite
MongoDB
Redis
Vitest
GitHub Actions

Case study Source Live

Selected work

Skills

50 technologies · 8+ years shipping to production

Core stack

TypeScript
React
Next.js
Node.js
Spring Boot
PostgreSQL
AWS
Kubernetes
Claude
LangChain

Languages04
- JavaScript
- TypeScript
- Java
- Shell Scripting
Frontend09
- React
- Next.js
- Angular
- Redux
- D3.js
- HTML5
- CSS3
- SCSS
- Material
Backend08
- Node.js
- Express.js
- NestJS
- Fastify
- KoaJS
- Spring Boot
- REST APIs
- JWT
AI06
- Claude
- LangChain
- Prompt Engineering
- Large Language Models (LLM)
- Retrieval-Augmented Generation (RAG)
- MCP Tool Design
Databases06
- MySQL
- PostgreSQL
- MongoDB
- Redis
- SQLite
- Qdrant
Cloud & DevOps04
- AWS
- Docker
- Kubernetes
- GitHub Actions

Also worked with · 13 more

Security: Role-Based Access Control
Platform & Tools: Linux · Windows · Xen · XenServer · Tcpdump · SSH · Hping · GDB · AWK · Xentools · AB2 · Vitest

Skills

Credentials

2 degrees · 2 publications · 10 certifications

Publications02

Conference paper · Springer Nature · 2022
Detecting Cloud Originated DDoS Attacks at the Source Using Out-Cloud Attack Detection (OCAD)
ICISS 2022 · LNCS vol. 13784
Gulshan Kumar Singh, Gaurav Somani
DOI
Book chapter · Springer · 2018
Cross-VM Attacks: Attack Taxonomy, Defense Mechanisms, and New Directions
Versatile Cybersecurity · Advances in Information Security vol. 72
Gulshan Kumar Singh, Gaurav Somani
DOI

Education02

2016 – 2018
Computer Science and Engineering
Master of Technology · Central University of Rajasthan
2012 – 2016
Information Technology
Bachelor of Engineering · Chhattisgarh Swami Vivekanand Technical University

Certifications10

Latest certification

Claude Certified Architect - Foundations

Anthropic · Issued Jul 2026

Valid until Jul 2027Verify

TypeScript Essential Training
LinkedIn · Jan 2024
Information Security
freeCodeCamp · Jun 2023

+7 more

Data Visualization
freeCodeCamp · Jun 2023
Back End Development and APIs
freeCodeCamp · Jun 2023
Front End Libraries
freeCodeCamp · Jul 2021
JavaScript Tutorial
Sololearn · Aug 2018
CSS Fundamentals
Sololearn · Aug 2018
HTML Fundamentals
Sololearn · Aug 2018
Java Tutorial
Sololearn · Aug 2018

Credentials

Contact

What's next?

Let's build something.

Open to principal and staff engineering roles, AI product work, and interesting collaborations. My inbox is always open.

Say hello

LinkedIn GitHub

Hyderabad / Bengaluruusually replies within a day

Gulshan Kumar Singh

What I do

Full-stack platforms

AI and RAG systems

Cloud and architecture

Core stack

Languages04

Frontend09

Backend08

AI06

Databases06

Cloud & DevOps04

Publications02

Detecting Cloud Originated DDoS Attacks at the Source Using Out-Cloud Attack Detection (OCAD)

Cross-VM Attacks: Attack Taxonomy, Defense Mechanisms, and New Directions

Education02

Computer Science and Engineering

Information Technology

Certifications10

Claude Certified Architect - Foundations

Let's build something.

Core stack

Languages04

Frontend09

Backend08

AI06

Databases06

Cloud & DevOps04

Publications02

Detecting Cloud Originated DDoS Attacks at the Source Using Out-Cloud Attack Detection (OCAD)

Cross-VM Attacks: Attack Taxonomy, Defense Mechanisms, and New Directions

Education02

Computer Science and Engineering

Information Technology

Certifications10

Claude Certified Architect - Foundations