Basant Patidar
8+ years shipping enterprise-scale distributed systems — from mutual fund platforms processing millions of daily transactions to a marketplace payments platform handling 2.5M+ daily payment requests.
01.
About Me
A little context behind the numbers.
I'm a Senior Full-Stack Developer who specializes in building distributed systems that handle real enterprise load — not toy scale, but millions of daily requests and financial platforms where downtime is not an option.
My career has taken me across three demanding domains. At Walmart, I currently build the seller-payments platform behind Walmart Marketplace — commission, settlement, and reconciliation across four countries — and previously led a healthcare migration that saved thousands of hours of pharmacy labor nationwide. At T. Rowe Price, I built and modernized the microservices backbone behind mutual fund transactions — millions of trades a day, 300+ funds, strict financial compliance.
I lead with architecture — I'm comfortable owning technical design documents, driving discussions across 30+ person organizations, and making the right call between pragmatism and elegance. Java and Spring Boot are my home base, but I'm equally at ease in the cloud (AWS, Azure), the data layer (Kafka, Cassandra, Cosmos DB), or the frontend (React, Angular).
Walmart
Seller-payments platform processing 2.5M+ daily requests across commission, settlement, and reconciliation.
T. Rowe Price
Mutual fund platforms processing millions of daily trades across 300+ funds.
Walmart Health & Wellness
Event-driven microservices saving 2,500+ hours of pharmacy labor every day.
02.
Systems Gallery
Interactive architecture diagrams from production systems I've built and scaled.
Sep 2025 – Present
Walmart — Marketplace Payments Platform
Engineer core services on Walmart Marketplace's seller-payments platform — commission, settlement, seller payouts, and reconciliation across the US, Canada, Mexico, and Chile. Migrated 30+ REST endpoints from a legacy Java monolith to containerized Spring Boot microservices on Kubernetes via canary releases. A parallel MCP layer exposes the same platform data to AI agents for migration parity-checking and domain tooling, and a Claude Agent SDK–based classifier feeds the Pay-on-Delivery reconciliation DAG by categorizing disputed cases and inferring partner intent.
- ▹2.5M+ daily payment requests
- ▹30+ endpoints migrated to microservices
- ▹12-stage reconciliation DAG for Pay-on-Delivery
- ▹Agentic reconciliation classifier (Claude Agent SDK)
Tech Stack
03.
Experience
The roles, the systems, and the scale behind the work.
- ▹Migrated 30+ REST endpoints from a legacy Java monolith to containerized Spring Boot microservices on Kubernetes via canary releases, serving 2.5M+ daily requests.
- ▹Engineered idempotency and concurrency controls for payment processing, resolving race conditions across distributed services to guarantee exactly-once settlement under high concurrent load.
- ▹Replaced Cassandra-based locking with a faster Redis distributed-locking mechanism (Hazelcast as an in-memory option), cutting lock-acquisition latency for concurrent access to shared payment state.
- ▹Built event-driven Kafka messaging for migrated payment services, integrating settlement ETL output and scheduled reconciliation jobs with downstream consumers.
- ▹Designed a Spring Batch–orchestrated DAG pipeline for Pay-on-Delivery reconciliation, sequencing 12 validation stages — order matching, payout calculation, and processor transmission — with dependency management and failure/retry handling.
- ▹Built a custom MCP server exposing payments-domain tools for AI-agent access to platform data, plus a custom Skill for automated migration parity-checking, and mentored junior engineers on the payments platform team.
- ▹Built an agentic reconciliation classifier using the Claude Agent SDK to categorize disputed payment cases and infer partner intent, driving automated response and resolution for the reconciliation workflow.
- ▹Integrated BNY Mellon Pershing and FactSet RESTful APIs to automate financial data retrieval for 300+ mutual fund products, RMD, and college savings accounts.
- ▹Led architectural design discussions and authored technical design documents engaging directly with product owners across a 30+ person organization.
- ▹Designed and deployed cloud-native services on AWS (EC2, S3, SNS, SQS), leveraging EMR for large-scale data processing within Spring Boot applications.
- ▹Managed multi-database systems including IBM DB2, PostgreSQL, and DynamoDB, ensuring data integrity across high-availability financial applications.
- ▹Migrated monolithic legacy systems to cloud-native microservices using Java 17 and Spring WebFlux, reducing pharmacy staff labor by 2,500+ hours per day across the United States.
- ▹Architected resilient event-driven data pipelines on Azure using Cosmos DB and Azure SQL with CI/CD orchestration via Concord for automated Kubernetes deployments.
- ▹Implemented Kafka-based event orchestration to synchronize Cosmos DB change feed updates with downstream API executions across distributed microservices.
- ▹Migrated the RMD service from Groovy to Java Spring Boot, modernizing 8–10 endpoints and implementing JPA/Hibernate to improve throughput and maintainability.
- ▹Built and maintained Angular/TypeScript frontend features using RxJS for reactive state management across fund transaction and portfolio views.
- ▹Conducted code reviews, led technical design discussions, and maintained high test coverage using JUnit 5 and Mockito within a 12-person Agile/Scrum team.
- ▹Built and maintained full-stack features using Spring MVC, Hibernate, and Oracle SQL within a 15-person engineering team.
- ▹Developed interactive campaign analytics dashboards using D3.js and HTML5 Canvas, delivering real-time SVG-based ad performance visualizations.
04.
Skills
Technologies I've used in production at enterprise scale.
Backend
Cloud & Infra
Data & Messaging
Frontend
DevOps & Monitoring
Testing & Methodology
AI-Assisted Engineering
05.
Get in Touch
Open to new opportunities and interesting projects. I'll get back to you within a day.
Whether you have a role in mind, a system to build, or just want to connect — drop me a message and let's talk.