UPI Payments Platform
Cloud-native payment processing platform powering UPI transactions for Kotak811. Built on event-driven microservices with high observability and resilience.
Location
Pune, Maharashtra, India
Hussain Pithawala
Financial Infrastructure Architect
I build programmable platforms for payments, lending, and experimentation. My work focuses on distributed workflow orchestration, event-driven systems, and cloud-native financial infrastructure.
AWS / K8s
Workflow Engines
Enterprise Architecture
About
Building scalable, fault-tolerant systems for modern financial platforms
Engineering systems that scale with business
With two decades in software engineering, I specialize in domain-driven design, distributed workflow orchestration, and cloud-native architecture on AWS. I am leading multiple engineering teams for UPI payments, credit-line origination, and real-time notification platforms at scale.
Languages
Go, Java, TypeScript, Python, Erlang, Elixir, Ruby, C/C++
Databases
PostgreSQL, MySQL, DynamoDB, Cassandra, Redis, MongoDB, OpenSearch/ElasticSearch
Streams
Kafka, SNS/SQS, RabbitMQ, ActiveMQ, Apache-Pulsar
Cloud & DevOps
AWS, Kubernetes, ECS, CI/CD, Observability
Workflow Engines
Camunda 7/8, AWS Step Functions, Temporal, AMZ state machines
Architecture
System-Design, HLD, LLD, Solution-Architecture, Audit
Platforms Built
Customer Engagement Platform (Ad-Roll)
In-house nudges platform serving personalized campaigns to 10M+ customers daily. Combines event streaming, rule engines, and experimentation frameworks.
Lending Workflow Platform
A programmable workflow engine supporting credit policy evaluation, A/B testing, shadow policy execution, and historical backtesting.
Co-Lending Infrastructure
Custom lending platform enabling partner banks to co-lend with automated loan splitting, servicing, and reconciliation.
Experience
Enterprise-scale systems for finance and payments
Senior VP
Kotak811
Full-time · Aug 2022 – Present · 3 yrs 5 mos
Pune, Maharashtra, India · Remote
1. 811 Payments Platform
Building resilient, compliant, high-scale financial platforms for retail banking
- Own the end-to-end UPI payments platform supporting 120M+ monthly real-time transactions across acquisition and issuance flows
- Lead engineering teams building cloud-native payment services integrated with NPCI and vendor switch ecosystems
- Driving Credit-Line on UPI platform expansion, integrating underwriting, disbursement, and reconciliation systems
- Oversee bank transfer infrastructure connecting the 811 technology stack with core banking for NEFT, IMPS, IFT, and RTGS
NestJS
Golang
AWS DynamoDB
AWS SQS/SNS
Cloud-Native
UPI
2. Kotak811 Nudges Platform (Ad|Banner-roll system)
Lead the development of an in-house personalization and growth orchestration platform (“Nudges Platform”) powering real-time cross-sell experiences for the Kotak811 mobile app.
The platform acts as a central decisioning layer for personalized engagement, continuously updating each user’s nudge inventory from multi-source signals:
- CleverTap customer journeys
- Data science recommendation models
- Domain service events from banking platforms
- Campaign configurations from growth and product teams
A state-machine-based workflow orchestration engine enables configurable rule execution and experimentation without redeploying services. A dedicated web operations portal supports campaign/nudge management, model iteration, and workflow administration across growth, product, data science, and engineering teams.
Currently powers 12M+ cross-sell decision calls daily, operated by a lean engineering team of three delivering scalable, highly configurable personalization infrastructure.
Golang
Gin
state-machine-amz-go
Kafka
Event-Driven
AWS
3. Unified Rewards Platform
Leading a team, which builds and operates a centralized rewards engine that aggregates events from multiple channels (payments, engagement, etc.) to deliver a unified, real-time customer rewards journey.
Java
Quarkus
Drools 8
AWS Kinesis
KCL v2
Event-Driven
3. Business Rules Engine – Assets Pipeline
Control Plane
- Spring-based reactive, non-blocking APIs abstracting multiple workflow engines
- Secure access via Keycloak + API Gateway + SAML IDP (SSO, RBAC)
Capabilities
- Back-testing: Run new policies on historical data
- Shadow mode: Compare policy outcomes without affecting production
- A/B experimentation with bucketed sampling
Includes a dedicated microservice for A/B experiment orchestration.
Data Plane
- Zeebe + open-source tools for BPMN workflows & DMN decisioning
- Custom µ-services for Zeebe job/task processing
- µ-service for orchestrating AWS Step Functions (straight-through processing)
Java
Camunda-8
Python
Pyzeebe
Custom development Zeebe
VP | Technical Architect
InCred Financial Services
Full-time · Jan 2022 – Jul 2022 · 7 mos
Pune, Maharashtra, India · Remote
Coached multiple teams on Domain-Driven Design, Trunk-Based Development, and AWS cloud architecture for distributed systems.
Incred's internal Colending platform
With a small three-member team, built the Colending platform for Incred. The platform supports co-lend loans sold by Incred Finance to other banks in India. The system was developed as a custom portal using Django|Python. For split loan management Apache Fineract was used.
Python
Django
Bootstrap
Apache Fineract
LMS
Real-Time Customer Engagement System
Mentored a team building a real-time event-driven engagement platform using AWS Kinesis, Pinpoint, and Amplify.
Quarkus
GraalVM
AWS Kinesis
KCL v2
AWS Pinpoint
Key Individual Contributions
- Built a CIBIL TUDF/TUEF parser/generator in Python for variable & fixed-length credit report files
- Designed an ANTLR4-based rule language for task-chain
evaluation in Loan Origination workflows
- github-link: fulfilment-rules
- Developed co-lending modules for loan splitting based on configurable criteria
- Customized Apache Fineract to support co-lending business logic
- Built a Django-based multi-tenant portal for co-lending loan management
Principal Engineer
InCred Financial Services
May 2021 – Dec 2021 · 8 mos
Pune, Maharashtra, India · Remote
#1 Partner API Gateway
Exposed partner APIs via AWS API Gateway with Cognito-based auth. Deployed using CloudFormation with Python/Shell automation scripts.
AWS API Gateway
AWS Cognito
CloudFormation
Python
#2 Loan Origination Workflow Engine
Designed a serverless workflow service using AWS Step Functions to orchestrate microservices for loan processing.
- AWS Step Functions for workflow execution
- AWS SNS/SQS for reliable message delivery
- AWS DynamoDB for state persistence
Node.js
Express
AWS Step Functions
DynamoDB
Serverless
#3 CI/CD for ML & Django Services
Built self-updating CI/CD pipelines using AWS CDK for Dockerized ML models (Lambda) and Django apps.
- AWS CDK Pipeline (TypeScript) for Lambda Docker images
- AWS CodePipeline for Django Docker deployments
- Full-stack provisioning including API Gateway via CDK
AWS CDK
TypeScript
Docker
CodePipeline
Lead Software Engineer
Deserve
Full-time · Dec 2019 – Apr 2021 · 1 yr 5 mos
Pune, Maharashtra, India · Remote
Led development of a cloud-native Credit Card Platform-as-a-Service (PaaS) enabling partners to issue VISA/Mastercard cards via multiple processors. Built as an event-sourced, domain-driven microservice architecture on AWS.
Platform Architecture & Responsibilities
- Led a team owning end-to-end domains: users, accounts, cards, payments, statements, and notifications
- Architected an event-driven system integrating card processors via synchronous and asynchronous channels
- Built core services on AWS with SNS/SQS for event streaming and Lambda for orchestration
Key Technical Contributions
Domain Microservices (Python)
Modeled entity lifecycles (cards, accounts, payments) as stateful domain services.
Python
Django
Flask
Domain-Driven Design
Gateway & Integration Layer (Elixir)
Built high-throughput integration gateways connecting to external card processors via REST and event streams.
Elixir
Plug
Cowboy
Broadway
REST
Event Streaming & Orchestration
Used AWS SNS/SQS for durable event delivery; Lambda functions route events to domain services.
AWS SNS/SQS
AWS Lambda
Event Sourcing
Cloud-Native
Software Engineer III
Trusting Social
Full-time · Dec 2018 – Nov 2019 · 1 yr
Pune/Pimpri-Chinchwad Area · Remote
Built and maintained a suite of microservices powering digital lending workflows — from product configuration to loan disbursement — integrated with banks, merchants, and internal underwriting systems.
Core Responsibilities
- Designed APIs and microservices for loan product management, user journey orchestration, and lender/borrower onboarding
- Integrated with external banks and merchants for real-time loan offers and disbursement
- Used Apache Fineract as the core Loan Management and Origination System (LOS)
- Built a rules-based underwriting engine using Drools for automated credit decisions
Tech Stack
Java 8
Node.js
Golang
Ruby on Rails
Apache Fineract
Drools
Microservices
REST APIs
Leadership
Leadership & Organizational Impact
Lead engineering teams responsible for building and operating mission-critical financial platforms across payments, engagement systems, and lending workflows for the Kotak811 digital banking ecosystem.
- Architecture Governance: Chair the Kotak811 Architecture Review Board (ARB), responsible for evaluating and approving technology proposals across engineering teams, ensuring alignment with platform strategy, scalability standards, and long-term architectural direction.
- Cross-Functional Platform Leadership: Work closely with product, business, and risk teams to translate strategic initiatives into scalable technology platforms, balancing regulatory requirements, operational resilience, and product velocity.
- Engineering Leadership & Mentorship: Mentor platform engineers, technical leads, and engineering managers, fostering strong engineering practices across distributed platform teams.
- Senior Engineering Hiring: Play a key role in building the senior engineering leadership bench, hiring for critical roles including Technical Architects, Engineering Managers, and Principal Engineers.
Engineering Philosophy & Platform Thinking
My engineering philosophy centers on building platforms rather than isolated systems.
In complex domains such as digital banking, payments, and lending, product velocity and operational resilience improve dramatically when engineering teams invest in reusable infrastructure, configurable workflows, and strong architectural foundations.
I focus on designing systems that enable small teams to operate large-scale platforms, emphasizing:
- Platform-first architecture: building reusable capabilities that multiple product teams can leverage.
- Configurability over code changes: enabling business teams to iterate quickly through workflow orchestration and self-serve tooling.
- Event-driven systems: allowing platforms to react dynamically to signals from multiple domains.
- Operational excellence: ensuring mission-critical financial systems remain resilient, observable, and scalable.
- Engineering leverage: maximizing impact by creating systems that amplify the productivity of product, growth, and data science teams.
This approach has shaped the development of platforms across payments infrastructure, engagement systems, and workflow-driven decision engines, enabling scalable innovation within regulated financial environments.
I believe the most valuable engineering leaders build systems where platform capabilities outlive individual products.
Services
Architectural leadership for mission-critical systems
Workflow Engine Design
I have extensive exposure and knowledge in customising, operating with prevailing solutions like Camunda, Temporal and Step Functions
At the same time I have also developed opensource state-machine-amz-* libraries|engines in multiple languages to cater to special cases where these solutions either cost very high or are not suitable
Cloud-Native Architecture
AWS, Kubernetes, ECS, serverless, and event-driven systems.
I have extensive experience in building cloud native microservice platforms over AWS cloud services, which linearly scale
Resilient Systems
Observability, data resilience, and fault tolerance for financial platforms.
Built and operated mission-critical payment, fintech services where latency of every millisecond counts
DevOps
AWS CDK, Terraform CDK, Azure DevOps pipelines, DR setup, Active-Active, Active-Passive, Multi-AZ setups
Distributed Systems Platform Lab
I build foundational primitives for distributed systems, workflow orchestration, and experimentation infrastructure.
Prayog: Experimentation Platform
A/B Testing · Multi-Armed Bandits · Thompson Sampling
A full-scale experimentation system to run A/B/n tests with advanced configurations. Supports real-time event streaming to multiple destinations (e.g., analytics, ML models).
Python
FastAPI
Cassandra
OpenTelemetry
Prometheus/Grafana
| Language | GitHub | Status |
|---|---|---|
| Python | prayog-api | Work in Progress |
Work in Progress
Implementation phase – expected Q2 2026
Workflow State Machine Engine
Distributed Orchestration · AWS States Language
A production-grade orchestration platform that runs complex workflows using Amazon States Language compatible definitions and event-driven execution primitives.
Architecture
- Control Plane → state definitions
- Execution Engine → state transitions
- Workers → service tasks
| Component | GitHub | Status |
|---|---|---|
| Execution Engine | state-machine-amz-go | Stable |
| Control Plane API | state-machine-amz-gin | Stable |
| Control Plane Portal | state-machine-amz-portal | Stable |
Distributed Business Circuit Breaker
Resilience · Multi-language · Real-time State Sync
A library to implement business-level circuit breakers that can be synchronized across services. Supports dynamic thresholds, failure windows, and real-time state propagation (via Redis, DynamoDB, or gRPC). Planned for Go, Java, and Python.
Go
Java
Redis
Event-Driven
Coming Soon
Design phase – expected Q2 2026
emv-qr-code-*
Encoder/Decoder library for EMV® QR Code payloads
Encoder/Decoder libraries for EMV® QR Code payloads as defined in the EMV QR Code Specification for Payment Systems (EMV QRCPS) – Merchant-Presented Mode v1.0.
| Language | GitHub | Status |
|---|---|---|
| Go | emv-merchant-qr-lib | Stable |
| TypeScript | emv-merchant-qr-lib-ts | Stable |
Core Technologies
Languages
Go · Java · Python · TypeScript · Elixir
Data Systems
PostgreSQL · DynamoDB · Cassandra · Redis
Event Infrastructure
Kafka · SNS/SQS · RabbitMQ · Pulsar
Cloud Platforms
AWS · Kubernetes · ECS · Serverless
Workflow Systems
Camunda · Temporal · AWS Step Functions · Custom State Machines
Contact
If you are building large-scale financial infrastructure or experimentation platforms, I would love to connect.
Phone
Please reach out to me on linkedin or email
hussainpithawala@hotmail.com