Open to Mumbai or remote

Mohd. Hussain Ansari

Software Development Engineer 2 · Back-end Engineering

Real-time systems, payments, and the boring parts of money.

Location
Mumbai, Maharashtra, India
Experience
4+ years
Currently
INK IN CAPS
Contact
mohd.hussainansari19@gmail.com
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01 / Signals

0+Concurrent WS connectionsSocket.IO + Redis, multi-server
$0KProcessed monthlyAcross ~7,700 transactions
0K+Users servedPayment-gateway workflows
0+Sellers migratedZero data loss
0.0MRecords re-indexedSchema + index optimisation
0%Query latency cutPost-migration
0%Feed load time cut~90% less data transferred
0Engineers ledBack-end and QA

02 / Profile

What I actually do

Back-end engineer with over four years designing and running production systems in Node.js, NestJS and TypeScript. My work sits where correctness matters most: payment and subscription lifecycles, wallet and ledger mechanics, and real-time infrastructure that has to stay consistent across many servers at once.

I design real-time WebSocket infrastructure on Socket.IO and Redis Pub/Sub, fanned out across multiple servers, currently carrying 3,000+ concurrent connections for messaging and notifications.

I work on payment and transaction processing — gateway workflows moving roughly $462K USD a month across about 7,700 transactions for 30K+ users, alongside subscription lifecycle, idempotency, retry, wallet and ledger functionality.

I take ownership of performance and migrations: 800+ sellers moved with zero data loss, schema and indexing reworked across 2.7 million records, and a 25% improvement in query latency.

I have led a 10-member cross-functional team of back-end and QA engineers, running requirement gathering, feature discussion, and product demos with founders and clients across London, Dubai and Canada.

Core competencies

  • Back-end development & architecture
  • Distributed & event-driven systems
  • Real-time infrastructure
  • API, webhook & third-party integration
  • Payment & subscription lifecycle
  • Database design & performance
  • Multi-tenant platform engineering
  • Wallet, ledger & transaction processing
  • Cloud infrastructure (AWS)
  • Background jobs & async workflows
  • Production reliability engineering
  • Code review, mentoring & ownership
  • Stakeholder engagement

03 / Selected Work

Systems I've built and run

Five production systems — real-time infrastructure, payments and ledgers, a national commerce protocol, and an app built to work with no network at all. Each entry links to the architecture behind it.

04 / Experience

Where I've worked

INK IN CAPS

Software Development Engineer 2

Dec 2025 — Present

Back-end engineering on a creator subscription platform: real-time messaging infrastructure, the subscription and wallet money paths, and the async job layer behind them.

  • —Designing real-time WebSocket infrastructure on Socket.IO and Redis Pub/Sub across multiple servers for live messaging and notifications.
  • —Managing the end-to-end subscription lifecycle — activation, renewal, expiry, invoicing, retries and failure recovery — with idempotency mechanisms that prevent duplicate charges.
  • —Building wallet and ledger functionality for credit, debit and balance tracking with atomic, consistent transactions.
  • —Running Redis-backed BullMQ queues so renewals, notifications and invoicing happen outside the request path.
  • —Developing signature-validated webhooks and push notification pipelines on AWS EC2, ALB, Route 53, Lambda, SES and S3.
  • —Redesigned a slow home-feed endpoint, cutting load time by ~75% and data transfer by up to 90% under typical usage.
AppOctet Technologies

Product Developer (Back-end)

May 2022 — Nov 2025

Progressed from mobile app developer to product developer — shipping React Native apps before taking ownership of back-end architecture, third-party integrations, code review, mentoring, and production releases across several products.

  • —Led back-end development across product engagements, owning architecture, reusable APIs, integrations, reviews, mentoring, production systems and releases.
  • —Drove back-end reliability by identifying recurring failure scenarios and strengthening error handling across production applications.
  • —Improved deployment through Docker-based automation — deploys following code push and a green test run, with less manual intervention.
  • —Led the technical migration of 800+ sellers with zero data loss, and optimised schema and indexing across ~2.7 million records for a 25% query latency improvement.
  • —Recognised as Star Performer in both 2024 and 2025.

05 / Stack

What I build with

Languages
TypeScriptJavaScript (ES6+)Java
Runtime & Frameworks
Node.jsNestJSExpress.js
Data
MongoDBMySQLPostgreSQLRedisMongooseTypeORMPrisma
Async & Real-Time
BullMQRedis Pub/SubSocket.IOWebSocketsAgendaDelayed jobsRetry strategies
Cloud & Infra
AWS EC2ALBRoute 53LambdaSESSQSS3CloudFrontDockerGit
Architecture
REST APIsWebhooks & signature validationEvent-driven systemsIdempotency & retriesWallet & ledger designSubscription lifecycleRBAC / CASL policies
Integrations
RazorpayCashfreeCentrobillShopifyOnfidoDelhiveryShiprocketONDCFirebaseWhatsApp APISlack
Testing & Observability
JestSupertestOpenTelemetrySignozNew RelicWinstonPinoSwagger
AI-Assisted Development
ClaudeGitHub CopilotChatGPT

06 / Recognition

Awards, education & certs

Achievements

Star Performer — 2024 & 2025

AppOctet Technologies

Recognised in consecutive years for product delivery and back-end performance work.

First Rank — B.Sc. Computer Science

Mumbai University

Graduated first in the Computer Science programme at Ismail Yusuf College.

ONDC Network Certification

Open Network for Digital Commerce

Led a logistics integration through ONDC protocol certification with 5+ partner organisations.

Education

B.Sc. Computer Science

Ismail Yusuf College, Mumbai University

2019 — 2022 · First Rank

Certifications

Generative AI MastermindOutSkill
Problem Solving (Basic)HackerRank
Algorithm EssentialsHackerRank
AI Tools WorkshopBe10x

07 / Contact

Let's talk

Open to back-end engineering roles, consulting, and interesting product conversations.

LocationMumbai, Maharashtra, India
LinkedInmohd-hussain-ansariGitHubMohd-Hussain-Ansari