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Deep-dive articles on System Design, Java, Kafka, Redis, AI/ML, and AWS — from an Engineering Manager with 10+ years building distributed systems at scale.

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10+
Articles
10+
Yrs Exp
7
Topics
Sachin Sarawgi

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In-depth guides and deep dives worth your time

AI/ML

Building a Production RAG System: Embeddings, Vector DBs, and Retrieval

Retrieval-Augmented Generation (RAG) is the most practical technique for making LLMs useful on your private data. Instead of hoping the model memorizes your documents during training (it doesn't), RAG retrieves relevant …

Feb 12, 2025·12 min read
#ai#llm#rag
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Java

Java 21 Virtual Threads: The End of Reactive Programming Boilerplate

For the past decade, Java developers dealing with high-concurrency IO-bound workloads faced an uncomfortable choice: write readable sequential code that does not scale, or write reactive/async code that scales but is not…

Feb 5, 202512 min read
#java#java21#concurrency
System Design

System Design: Building a URL Shortener That Handles Billions of Requests

The URL shortener is the "Hello World" of system design interviews — but most candidates treat it superficially. The interesting parts are not in generating a short code; they're in the numbers that reveal the true scale…

Jan 29, 202512 min read
#system design#distributed systems#databases
Databases

Redis Beyond Cache: Sorted Sets, Streams, and Pub/Sub Patterns

Most teams use Redis for one thing: caching. They store objects with a TTL, check the cache before hitting the database, and call it a day. This barely scratches the surface. Redis is a data structure server. Its real po…

Jan 22, 202513 min read
#redis#cache#java
Messaging

Kafka Internals Deep Dive: Partitions, Offsets, and Consumer Groups

Apache Kafka is the de facto standard for event streaming in distributed systems, but most developers treat it as a black box — a durable message queue with a fancy name. Understanding Kafka's internals unlocks its true …

Jan 15, 202510 min read
#kafka#distributed systems#streaming
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About Me

Who I Am

I'm a Technical Lead / Architect at Redwood Software, with over 10 years of backend engineering across fintech, enterprise SaaS, and early-stage startups.

I've worked at Paytm, ServiceNow, Threado AI, Paysafe, Accion Labs, and TCS — building systems that process payments at scale, integrating enterprise platforms, and leading teams through complex data migrations and architectural transitions.

CodeSprintPro is where I share what I've learned from building production systems — the real patterns, the real trade-offs, and the decisions that only make sense once you've seen a system fail at 2am.

Technical Stack

Languages & Frameworks

JavaSpring BootSpring CloudSpring Security

Data & Messaging

KafkaRedisMySQLPostgreSQLElasticsearchPresto

Infrastructure & Observability

AWSDockerPrometheusGrafanaDatadogNew Relic

Architecture

MicroservicesSystem DesignDistributed SystemsREST APIs
10+
Years of experience
7
Companies across fintech, SaaS & startups
62+
Technical articles published

Work Highlights

Selected projects from 10 years of building backend systems across payments, enterprise SaaS, and startups.

Paytm2023 – 2025

Staff Software Engineer / Senior Technical Lead

PSP Device Binding Migration & Merchant Invoicing

  • →Led migration of 20 GB+ of user PSP binding data with zero downtime — served millions of active Paytm users
  • →Built and shipped new device binding APIs for the mobile platform, improving security and reducing unauthorized access
  • →Replaced heavy code-based merchant file processing with Presto-powered SQL pipelines, cutting invoicing turnaround and eliminating per-config code changes
  • →Led deployment team through critical production rollouts; used shell scripting to resolve live device binding incidents
JavaSpring BootKafkaRedisMySQLPrestoPrometheusGrafana
ServiceNow2019 – 2022

Independent Contributor II & III

Azure, Jira & DevOps Integrations — Marketplace Apps

  • →Architected and shipped Azure and Jira integration apps now available in the ServiceNow Store
  • →Contributed to the ServiceNow Agile Development 2.0 family plugin, used by enterprise customers globally
  • →Led security remediation across the product using Fortify static analysis — identified and resolved critical vulnerabilities
JavaServiceNowAzureJiraREST APIsFortifyJenkinsDocker
Paysafe Group2018 – 2019

Platform Engineer

Real-Time Transaction Analytics Platform

  • →Built a merchant analytics platform that processed payment transactions in parallel using MapR Stream
  • →Enriched raw transaction data and surfaced insights into merchant dashboards via Elasticsearch and Druid
  • →Designed Spring Boot / Spring Cloud REST APIs powering the analytics front-end
Spring BootSpring CloudMapR StreamElasticsearchDruid

Writing & Community

CodeSprintPro

30+ in-depth articles on Kafka, Redis, System Design, Java 21, AWS, and distributed systems — the site you're reading right now.

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Medium

Earlier writing on Java, Spring Boot, and system architecture. 100K+ views across published articles.

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StackOverflow

Active contributor with answers focused on Java, Spring Boot, and database optimization.

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Get In Touch

Feel free to reach out for collaborations, opportunities, or just a friendly chat about technology and software development.