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Covalid
About
Santosh Chakraborty

Santosh Chakraborty

Principal Software Engineer @ Darwinbox · LLM Developer

Backend PHP PHP · Laravel Node.js LLMs Python System Design

About

I'm a Principal Software Engineer at Darwinbox, where I work on building large-scale HR technology that serves millions of users worldwide. With over a decade of experience across backend systems, distributed services and developer platforms, I focus on engineering things that are simple, robust and a pleasure to use.

Outside the day job, I'm an active LLM developer — building local-first tools, fine-tuning open models, and exploring how language models can be embedded directly into real product workflows. Covalid is one of those experiments: a tiny, dependency-free chat UI for talking to a locally-served model.

I enjoy clean architecture, careful APIs, and writing code that doesn't need a manual to understand. When I'm not at a keyboard, I'm usually reading, tinkering with hardware, or chasing a good cup of coffee.

What I work on

  • Backend platforms & distributed systems at scale
  • API design, performance, and developer experience
  • Local-first AI tooling and LLM integrations
  • Prompt engineering, evals, and small-model fine-tuning
  • Open-source experiments — like the one you're using right now

About Covalid

Covalid is a minimal, framework-free chat UI written in pure PHP, HTML and JavaScript. It talks to a local model via a small PHP proxy, keeps your conversations on your machine, and stays out of your way.

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