About

The engineer behind the work.

Bitan Sarkar, Software Engineer

Kolkata, India

I'm a Software Engineer based in Kolkata, India, currently at Publicis Sapient where I've spent the last 5+ years building and scaling backend systems for Omantel, one of Oman's largest telecom operators, serving over a million subscribers.

My stack centers on Java, Spring WebFlux, and AWS. I've led migrations from IBM WebSphere to cloud-native microservices, built SAML/SSO identity flows from scratch, and managed cross-region DynamoDB migrations under production load. I hold the AWS Solutions Architect – Associate certification.

Outside work, I'm a LeetCode Guardian (315+ problems), actively studying Blockchain and Web3, and writing about system design. I graduated from IIT Bhubaneswar with a BTech in ECE in 2021.

5+

Years at Publicis Sapient

2500+

LeetCode Rating

450+

LeetCode Problems Solved

AWS SAA

Solutions Architect

Journey

Education & Experience

From IIT Bhubaneswar to telecom-scale systems.

  1. 2017

    Joined IIT Bhubaneswar

    B.Tech Electronics & Communication Engineering

    Moved to Bhubaneswar to study ECE at IIT BBSR. Joined Coding Society and Chamber of Product. Began competitive programming.

  2. 2018-2021

    Campus Involvement

    Coding Society · Chamber of Product · DSC IIT BBSR

    Built IIT BBSR Campus Map Android app. Active in coding competitions. Member of Developer Student Club.

  3. 2021

    Graduated IIT Bhubaneswar

    B.Tech ECE, 2017-2021

    Completed BTech in Electronics & Communication Engineering.

  4. 2021

    Joined Publicis Sapient

    Software Development Engineer I

    Started as SDE-1. Assigned to Omantel (Telecom, Oman), a major IBM WebSphere to AWS microservices migration.

  5. 2022

    AWS Certified

    Solutions Architect – Associate

    Passed AWS SAA certification. Led PTT t-ecosys infrastructure design using Terraform and AWS.

  6. 2023-2024

    Telecom Platform Deepdive

    Omantel CXP: Auth, SAML, WebFlux

    Built SAML/Theqa SSO integrations, AWS Cognito auth flows (v1/v2), Spring WebFlux reactive microservices, DynamoDB migrations (52 tables across regions). Became go-to engineer for high-risk platform items.

  7. 2025-Present

    Systems & AI Expansion

    eBPF · LLMs · Blockchain · Competitive Programming

    Building KCPM (Kubernetes process monitor via eBPF/libbpf), RAG chatbot with LangChain/Ollama, exploring Blockchain/Web3. LeetCode Guardian badge. Targeting FAANG/top product company.

Toolbox

Skills & Technologies

Color-coded by proficiency: green is expert, amber proficient, blue actively learning.

Languages

JavaPythonGoJavaScriptSQLC

Backend

Spring BootSpring WebFluxNode.jsWebSphere (WAS)GraphQLREST APIs

Cloud

AWS LambdaAWS API GatewayAWS CognitoAWS DynamoDBAWS CloudWatchAWS EventBridgeAWS S3 + CloudFrontAWS EC2AWS SNS

DevOps

TerraformDockerKubernetesArgoCDGitLab CI/CDeBPF / libbpf

Databases

DynamoDBOracle DBMongoDBNeo4jRedis (ElastiCache)

Protocols

SAML / SSOOIDC / OAuth2SOAP

Tools

SonarQubeBrunoOpenVPN

Beyond Code

When I'm not coding…

Competitive Programming

LeetCode Guardian with 315+ problems solved. I keep the algorithmic muscles sharp.

History & Physics

Fascinated by the era of 1850 to 1950: the science, the people, and the ideas that shaped modernity.

Biblical Studies

A long-running personal study: texts, history, and interpretation.

What I Do

Three things I do well

Backend Engineering

Reactive microservices with Spring WebFlux. High-throughput APIs. Authentication systems (SAML, OIDC, Cognito). Built for production scale.

Cloud & AWS

Lambda, API Gateway, DynamoDB, Cognito, EventBridge, CloudWatch, S3, CloudFront. AWS SAA certified. Infrastructure as code with Terraform.

System Design

URL shorteners, auth architectures, serverless pipelines. I document architectural decisions, and my URL shortener article has been widely read on LinkedIn.

Selected Work

Featured Projects

A few things I've built and shipped, from serverless tooling to system-design write-ups.

All projects
Cloud

IRCTC PNR Status Notifier

Serverless PNR status tracker with automatic SMS/email alerts when waitlist clears.

PythonAWS LambdaEventBridgeSNSServerless
Code
DevTools

CloakVPN

Fully automated, GUI-powered VPN system. Terraform provisions OpenVPN EC2s across AWS regions, rotating IPs on demand.

PythonTerraformAWS EC2OpenVPNDevTools
Code
Web Applications

Splitwise Clone

A full-stack expense sharing application with group management and debt simplification algorithms.

Full-StackExpense TrackingWeb DevelopmentAlgorithmsSelf-Hosted
Code
DevTools

Redis Cluster SSM Proxy

Reaches a VPC-locked Redis Cluster through a single SSM port-forwarding tunnel.

Node.jsRedis ClusterElastiCacheAWS SSMNetworking
Code

Certification

AWS Solutions Architect – Associate

Designing distributed, resilient and cost-optimized systems on AWS.