---
title: "Shwet Raj - Software Engineer in Bengaluru | Tal"
description: "Meet Shwet Raj, Software Engineer | Java, Spring Boot, Distributed Systems, AWS, Kafka, PostgreSQL | Building Payments & Ledger Infrastructure based in Bengaluru. AI stack includes claude code, claude, and cursor. Explore public work links including github and leetcode."
image: "https://tal.club/meet/shwet-raj/share-image"
---

# Shwet Raj on Tal

## Headline

Software Engineer \| Java, Spring Boot, Distributed Systems, AWS, Kafka, PostgreSQL \| Building Payments & Ledger Infrastructure

## About

Backend engineer \(\~2 years\) building production payment and ledger systems in Java/Spring Boot\. At Callisto Infotech, I shipped multi\-tenant infrastructure serving 100K\+ users — checkout, idempotent webhooks, 50K events/day pipelines, and observability for 8\+ services\. Outside work, I'm building a fintech\-grade billing & payments engine \(linked below\): 21 domain modules, 970\+ classes, 94 tables, double\-entry ledger with DB\-trigger\-enforced immutability, 3\-layer idempotency, transactional outbox with lease \+ heartbeat, ASC 606 revenue recognition, and 2000\+ tests\. It's me trying to learn how Stripe, Razorpay, and Adyen actually engineer financial correctness at scale\. What I care about: correctness under concurrency, money math you can audit, systems you can operate at 3am\. Stack: Java 17, Spring Boot, PostgreSQL, Redis, Kafka, Docker, AWS\. C\+\+ for competitive programming \(700\+ LeetCode, 250\+ Hard, top 5% contests\)\. Open to senior backend / SDE\-2 roles in fintech, payments, or core infra\. Bangalore or remote\. https://github\.com/ishwetraj17/payments\-and\-ledger\-engine

## Location

Bengaluru

## AI stack

claude code

claude

cursor

openai

## Work experience

Software Engineer at Callisto Infotech, Mar 2024 \- Present · 2 yrs 9 mos, Remote, \- Architected production multi\-tenant backend across SaaS and e\-commerce verticals for 50\+ business clients, 100K\+ end users, service isolation, fault boundaries, 40% fewer integration failures, launch cycles cut 6 weeks → 2 weeks\. \- Built payment integration end\-to\-end — checkout, order flow, webhook handling, and idempotent retry logic across 80\+ endpoints\. Zero double\-charges, auth incidents cut from 20/year to near\-zero, scaled to 100K\+ users\. \- Engineered order/transaction event pipeline at 50K events/day, 500 events/sec peak with exactly\-once semantics and Redis deduplication — zero dropped order events, 35% faster incident response\. \- Optimized 30\+ data paths across order, catalog, and payment tables — composite \+ partial indexes, N\+1 elimi\- nation\. p95: 500ms → 300ms, \+30% throughput, handled 50% more load without scaling\. \- Built real\-time observability layer with per\-transaction audit trails — structured logging, distributed tracing, 500\+ metrics across 8\+ services\. Incident resolution hours → 20 minutes, 10× faster RCA\.

Software Engineering Intern at Callisto Infotech, Dec 2023 \- Feb 2024 · 3 mos, On\-site, \- Shipped multi\-threaded log ingestion system \(Java\) processing 500MB\+ daily logs, zero loss\. Throughput 50 → 75 MB/hr \(1\.5×\), now powers all 3 verticals\. \- Designed lock\-free concurrency patterns with formal lock ordering — 30% fewer failures, enabled safe con\- current job scheduling\. \- Profiled and optimized heap/CPU hotspots \(VisualVM, GC tuning\) — 20% peak memory reduction, critical for real\-time processing\.

## Education

Bachelor of Technology, Computer Science, University of Engineering & Management \(UEM\)

Senior Secondary \(10\+2\), Resonance International School

## Public links

- github: https://github\.com/ishwetraj17
- leetcode: https://leetcode\.com/ishwetraj2

[View the original profile](https://tal.club/meet/shwet-raj)

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