MK
Available for opportunities

Mohit Kumar

I architect distributed financial systems that move money and digital assets safely at scale.

Event-driven architecture. Zero-downtime migrations. Real-time disbursement pipelines. Currently engineering digital asset infrastructure at Publicis Sapient / Galaxy Digital.

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About

Engineering philosophy

I care about systems that are correct before they are fast, boring before they are clever, and observable before they scale. Everything else follows.

Languages

JavaPythonSQLJavaScriptTypeScript

Backend

Spring BootMicroservicesREST APIsEvent-Driven ArchitectureWebSockets

Data & Streaming

Apache KafkaRabbitMQRedisPostgreSQLMongoDBElasticsearch

Cloud & Infra

AWS (EKS, EC2, S3, CloudFront)KubernetesDockerTerraformJenkinsCI/CD

Observability

OpenTelemetryGrafanaDatadogDistributed TracingSLO/SLI

Practices

System DesignDistributed SystemsAPI DesignCode ReviewAgile

Career

Experience

Publicis Sapient/ Galaxy Digital

Software Development Engineer II

Aug 2024 – Present·Gurugram, India
  • ·Engineered digital asset transfer workflows integrating Fireblocks and institutional exchanges with idempotent transaction handling and distributed state reconciliation
  • ·Built threshold-based rebalancing engine redistributing assets across trading, lending, and operational accounts with automated derisking to Fireblocks vaults
  • ·Developed exchange connectivity workflows standardizing deposit/withdrawal operations across institutional trading venues, reducing manual reconciliation overhead
  • ·Executed zero-downtime migration of 50+ backend microservices from EC2 to EKS with phased deployment rollouts across production trading environments
  • ·Designed organization-wide Kafka migration framework for MSK to Confluent Cloud transition, building bidirectional replay infrastructure for safe traffic cutovers
  • ·Instrumented distributed services with OpenTelemetry and Datadog dashboards for production migration visibility and exchange workflow monitoring
KafkaKubernetesAWS EKSFireblocksOpenTelemetryDatadogSpring BootPostgreSQL

Pine Labs

Software Engineer

Jun 2022 – Aug 2024·Noida, India
  • ·Architected backend for Apple Pay Later with HDFC Bank — eligibility engine, approval workflows, and real-time disbursement pipelines serving millions of users
  • ·Launched Flexi Credit lending platform processing INR 150M+ monthly across 85,000+ merchants with instant approvals up to INR 500K
  • ·Re-architected legacy batch merchant onboarding into real-time event-driven pipeline with Kafka and Redis, reducing end-to-end latency from hours to sub-10 seconds
  • ·Built AML and fraud detection systems saving INR 360M+ in risk exposure; integrated HDFC, ICICI, and Kotak APIs for real-time BNPL credit checks
JavaSpring BootKafkaRedisPostgreSQLElasticsearchAWSMicroservices

Adda247

Software Developer

Mar 2021 – Mar 2022·Gurugram, India
  • ·Implemented CloudFront and Redis caching reducing P90 API latency from 800ms to 150ms and cutting database load by 70% for 10M+ monthly active users
  • ·Led StudyIQ platform integration designing unified data models and REST APIs for cross-platform revenue tracking workflows
  • ·Built multilingual platform support for dynamic content workflows enabling localization across regional languages at scale
JavaSpring BootCloudFrontRedisMySQLREST APIs

Portfolio

Featured Projects

Enterprise systems & distributed architectures built at scale — serving millions of users across banking, credit, and trading platforms.

Pine Labs

Apple Pay Later

Backend architecture for Apple Pay Later with HDFC Bank — eligibility engine, approval workflows, and real-time disbursement pipelines serving millions of users.

Engineering Challenge

Building a production-grade BNPL system that integrates with Apple Pay ecosystem while maintaining sub-200ms response times for eligibility checks and real-time disbursement decisions.

Millions
Users Served
< 200ms
Response Time
HDFC
Bank Partner
JavaSpring BootKafkaPostgreSQLAWSMicroservices
Apple Pay BNPL Architecturep99 < 200ms
Apple WalletiOS AppmTLS GatewayOAuth2 GuardEligibilitySub-200ms EngineHDFC BankISO8583 APIAWS MSK KafkaDisbursement DB
mTLS Security
Apple Wallet Rail
Redis Cache
< 10ms Scoring
Kafka Ledger
Dual-Publishing

Pine Labs

Flexi Credit

BNPL lending platform processing INR 150M+ monthly across 85,000+ merchants with instant approvals up to INR 500K.

Engineering Challenge

Re-architecting legacy batch onboarding into real-time event-driven pipeline while building comprehensive AML/fraud detection preventing INR 360M+ in risk exposure.

INR 150M+
Monthly Volume
85,000+
Merchants
INR 360M+
Risk Prevented
JavaSpring BootKafkaRedisElasticsearchAML
Flexi Credit BNPL PlatformActive Production
INR 150M+
Monthly Volume
85,000+
POS Merchants
INR 360M
Risk Prevented
AML & Fraud Detection92% Block Rate
Onboarding Latency: < 10sMax Limit: INR 500,000
Bank Integration: HDFC • ICICI • KotakAsync Kafka

Adda247

Adda247 — Scale Engineering

Performance optimization for 10M+ MAU platform — reduced P90 latency 81% and DB load 70% through CDN and caching architecture.

Engineering Challenge

Scaling an edtech platform from 800ms P90 latency to 150ms while handling 10M+ monthly active users with CloudFront and Redis caching strategy.

81%
Latency Drop
70%
DB Load Cut
10M+
Monthly Users
JavaSpring BootCloudFrontRedisMySQLCDN
Adda247 P90 Latency Benchmark10M+ MAU
Legacy EC2 Monolith P90800ms
AWS CloudFront + Redis P90150ms
81% Latency Drop
70% DB Load Cut
CloudFront Edge CachingStudyIQ Revenue API Unified

Open Source

TradeBot — Algorithmic Trading

Distributed algorithmic trading system with live/paper modes, WebSocket streaming, broker integrations, and risk management.

Engineering Challenge

Building a production-grade trading system supporting both live and paper trading with real-time market data streaming, encrypted broker integrations, and comprehensive risk controls.

Live / Paper
Modes
WebSocket
Streaming
Distributed
Architecture
JavaSpring BootPythonWebSocketsPostgreSQLRedis
TradeBot Order Book StreamLive & Paper Mode
Price (USD)SizeExecution
45,230.501.25Limit Sell
45,225.000.85Market Sell
45,215.202.40★ Executed
45,210.001.80Limit Buy
WebSockets Stream: Zerodha • BinanceTimescaleDB Ledger

Engineering Blog

Technical Writing

Deep dives into distributed systems architecture, event streaming migrations, and production cloud infrastructure.

16 min read
Event-Driven

Zero-Downtime Event Streaming Migration: RabbitMQ to AWS MSK Kafka

A complete technical specification for migrating event-driven microservices from RabbitMQ to AWS MSK Kafka with Avro schema registry enforcement, dual-publishing bridge, DLQ replay tools, and zero data loss.

Read the migration strategy & diagrams
14 min read
Cloud Infrastructure

Zero-Downtime Migration: Spring Boot Microservices from EC2 to Kubernetes

How we migrated core Spring Boot backend applications from legacy EC2 instances to AWS EKS with NGINX reverse proxy bridging, ConfigMaps externalization, AWS Secrets Manager, and JSON production logging.

Read the migration plan & topology
12 min read
Distributed Systems

MSK to Confluent Cloud: Enterprise Kafka Replay & Rollback Framework

Designing a bidirectional replay infrastructure for safe Kafka migration from AWS MSK to Confluent Cloud with offset tracking, multi-phase cutovers, and fail-safe rollback workflows.

Read the framework deep dive

Get in Touch

Let's build something together.

I'm always interested in hearing about challenging engineering problems, distributed systems architecture, or opportunities to build something meaningful.