About

Backend engineer, dual-degree physicist, and reluctant vim evangelist.

Hi, I’m Darshan Bagrecha — a backend engineer based in Bengaluru, India. I build authorization and identity systems for a living, and I write here about the software, AI, physics, and mathematics that keep me up at night.

What I do

I’m a Software Engineer at TELUS Digital, where I work on the systems that decide who is allowed to do what. A few things I’ve had a hand in:

Scaling a unified authorization engine to 6M+ daily access requests, building its Go and Open Policy Agent (OPA) caching and policy pre-compilation layer for low-latency lookups.
Owning a zero-downtime migration of 1M+ users off Auth0 to a custom OAuth2/OIDC layer — a just-in-time re-authentication strategy with zero forced password resets that saves $120K+ annually.
Onboarding 1.5K+ microservice APIs onto a unified security model with fine-grained attribute-based access control (ABAC), custom predicates, and organization scoping.
Cutting security-policy propagation from a 20-minute deploy cycle to under 5 seconds, and halving a role-resolution API’s p95 latency from 7s to 3s by rethinking a recursive CTE and its PostgreSQL query plan.

Before converting to a full-time role, I interned on the same team — building a Go (Gin) expert-skills service over 6M+ user profiles and making our RabbitMQ event pipelines idempotent and loss-proof with dead-letter recovery.

Things I build for fun

A database engine from scratch — a persistent storage engine in Go with an on-disk B-tree, page management, a key-value interface, and transaction support with concurrent readers and writers.
This blog — a zero-framework technical blog in vanilla HTML/CSS/JS, wiring up MathJax for equations, MathBox.js for interactive visualizations, and PrismJS for syntax highlighting.

Background

I hold a dual degree from BITS Pilani — a B.E. (Hons.) in Electronics and Instrumentation and an M.Sc. in Physics (2020–2025). The physics half is why half the posts here are about the universe and not about caching.

Toolbox

Expertise: Authentication and authorization (Auth0, OAuth2/OIDC), RBAC/ABAC, Open Policy Agent (OPA), microservices, event-driven systems.
Languages: Go, Java, Python, SQL, TypeScript, C.
Frameworks & infra: Gin, FastAPI, RabbitMQ, React.
Databases & caching: PostgreSQL, MongoDB, Redis.

Elsewhere

Find me on GitHub and LinkedIn, or say hello at darshanbagrecha1729@gmail.com.