Biraj
i sometimes build things from scratch to understand how they work, play chess (1900 rapid on lichess), badminton, and read books.
github.com/biraj21
x.com/biraj21_
lichess.org/@/biraj21
linkedin.com/in/biraj21
work experience
(you can click on the role summary to see the details)-
Shellular -
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co-founder & CEO
Shellular lets you remotely use your dev environment from your phone.
- works with laptops, desktops, Mac minis, EC2 boxes, Hetzner servers, DigitalOcean droplets, and any VPS that can run Node.js.
- gives you AI agents like Codex, Claude Code, OpenCode, Pi & more; persistent terminals without tmux; local files & git repos; code editor, git client and localhost tunnels with browser DevTools.
- runs over an end-to-end encrypted relay, has roughly 80 DAUs, and is open source.
- accepted into the Founders Inc Off Season II program, in-person in San Francisco.
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Hanging Piece -
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founder
Hanging Piece is an AI chess coach that explains your mistakes in plain English.
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Outspeed -
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founding engineer
realtime voice AI at Outspeed.
- developed a WebRTC-based real-time voice AI agent system using a message-driven Actor Model architecture for concurrent runtime units.
- designed the system around the OpenAI Realtime API specification and built the React SDK for developer integrations.
- implemented voice activity detection and semantic turn-taking using Silero VAD, so agents could skip turns, avoid bad interruptions, and end conversations naturally.
- built real-time log monitoring infrastructure that shipped cloud logs to Grafana Loki and streamed them to the frontend via SSE.
- automated AWS deployments with Terraform and Nomad, and used ClickHouse for high-throughput analytics (~3M+ events/day) with async inserts and materialized views.
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LaneSquare Technology Pvt. Ltd. -
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software developer -
built core pieces of thinkstack.ai, a multi-tenant B2B AI support platform for deploying customer-support chatbots on top of company knowledge bases.
- shipped core product surfaces across the GraphQL backend, Flask AI services, RAG, Redis-backed caching & queues, and AWS services including Cognito, S3, and API Gateway.
- built the knowledge-base answer pipeline with Pinecone-backed retrieval, crawler status tracking, and dashboard events for long-running ingestion jobs.
- designed the conversation routing layer using tool-calling for lead capture, ticket creation, and human handoff.
- built tenant isolation and access control: sub-users, RBAC roles/permissions, and API-key authentication for external integrations.
- created Zapier, Slack, WhatsApp, Facebook Messenger, and Instagram integrations for Thinkstack.
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software developer intern -
migrated Pickcel's backend codebase from node 12 to Node 18. also learned Docker.
- worked with TypeScript, Node.js, and Mongoose to update and optimize existing REST APIs by making some things concurrent. set up integration testing CI using GitHub Actions.
- optimized Dockerfile for our on-premise setup by properly reordering layers, reducing consecutive build times and improving cache utilization. also added Redis to the stack.
- introduced semantic git commits, coding conventions, and structure, which is now embraced by all developers in the organization.
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skills
- programming languages: JavaScript, TypeScript, Python, Go, C, Bash
- libraries and frameworks: React, Node.js, Express.js, FastAPI, GraphQL
- infra & tooling: Docker, AWS, Terraform, GitHub Actions, HashiCorp Nomad
- database & analytics: MongoDB, MySQL, Redis, Firebase Firestore, ClickHouse
- auth & payments: Better Auth, Supabase, Firebase, OAuth, Stripe, Razorpay
projects
LLM serving engine from scratch
a toy LLM server built from scratch with batched inference, auto-regressive generation loop for token
streaming, request queueing, and independent sequence completion. supports both streaming and non-streaming
responses via FastAPI. also includes Whisper for STT.
DotDB: in-browser vector database
a lightweight vector database that runs entirely in the browser. supports cosine similarity search,
persistent storage via IndexedDB, and batch operations. uses transformers.js with bge-small-en-v1.5 for generating embeddings. implements brute-force k-NN search with Float32Array for memory efficiency.
try it
Focker: Linux containers
Focker is a toy container runtime written in Go to understand Docker internals. implements Linux namespace
isolation (PID, mount, UTS), runs processes inside an extracted Ubuntu 22.04 root filesystem, and supports
bind mounts for sharing host directories with containers.
NumPy from scratch in Go
i was implementing neural networks from scratch in Go, and as a byproduct of it, i created my own version of
NumPy for tensor operations like +, -, *, /, matrix multiplication, transpose, etc. it also supports
broadcasting.
TCP server
a single-threaded TCP server written in C with an event loop using the
poll() system call, without any third-party library. the server listens on a port and echoes back
received data. i've also written a simple client to test the server.
Obsy: AI observability platform
Obsy is an AI observability tool that provides insights into AI operations. it has a Node.js SDK that
automatically instruments OpenAI, Pinecone and Vercel's AI SDK. the dashboard shows LLM trace, with timing
and usage metrics for each stage. built this in a hackathon.
Gomon: nodemon for Go files
a CLI tool to run Go programs in watch mode. to watch for changes, it uses kqueue() system call on
macOS and inotify on Linux. no third-party dependencies.
Other
brainfuck interpreter | JSON parser | nano-like CLI text editor | AI search | web crawler | tensor visualizer (demo) | findREp | AI Anywhere