---
title: "Rumman Hussain Siddiqui (@rumman90) | Hashnode"
description: "Technical Lead at Ain Finance. Read the latest articles by Rumman Hussain Siddiqui on Hashnode."
url: "https://hashnode.com/@rumman90"
---

@rumman90

# Rumman Hussain Siddiqui

@rumman90 · Karachi, Pakistan · Joined May 2026

Technical Lead at Ain Finance

### [Building a Knowledge Graph RAG Playground with PostgreSQL, Neo4j, and OpenAI](https://rummansystems.hashnode.dev/building-a-knowledge-graph-rag-playground-with-postgresql-neo4j-and-openai?utm_source=hashnode&utm_medium=feed)

An engineering walkthrough of a RAG playground for comparing Vector Search, Graph Search, and Hybrid Retrieval.

14 min read · [rummansystems.hashnode.dev](https://rummansystems.hashnode.dev/building-a-knowledge-graph-rag-playground-with-postgresql-neo4j-and-openai?utm_source=hashnode&utm_medium=feed)

[Jul 1](https://hashnode.com/posts/building-a-knowledge-graph-rag-playground-with-postgresql-neo4j-and-openai/6a4519641a1e6be12f54da83)

### [Testing Index Assumptions Across PostgreSQL, MySQL, SQL Server, and Oracle](https://rummansystems.hashnode.dev/testing-index-assumptions-across-postgresql-mysql-sql-server-and-oracle?utm_source=hashnode&utm_medium=feed)

A small fintech schema, four optimizers, and a few execution plans that did not behave the same way

13 min read · [rummansystems.hashnode.dev](https://rummansystems.hashnode.dev/testing-index-assumptions-across-postgresql-mysql-sql-server-and-oracle?utm_source=hashnode&utm_medium=feed)

[Jun 22](https://hashnode.com/posts/testing-index-assumptions-across-postgresql-mysql-sql-server-and-oracle/6a38e01b5fcc3d4dfeb66f7f)

### [Building a Document Intelligence Platform with NestJS, n8n, and PostgreSQL](https://rummansystems.hashnode.dev/building-a-document-intelligence-platform-with-nestjs-n8n-and-postgresql?utm_source=hashnode&utm_medium=feed)

What I Learned About Service Boundaries, Workflow Ownership, and Failure Handling

20 min read · [rummansystems.hashnode.dev](https://rummansystems.hashnode.dev/building-a-document-intelligence-platform-with-nestjs-n8n-and-postgresql?utm_source=hashnode&utm_medium=feed)

[Jun 13](https://hashnode.com/posts/building-a-document-intelligence-platform-with-nestjs-n8n-and-postgresql/6a2d3ca64a3b527785dd7143)

### [Blockchain Meets Distributed Systems: The Similarities Most Engineers Overlook](https://rummansystems.hashnode.dev/blockchain-meets-distributed-systems-the-similarities-most-engineers-overlook?utm_source=hashnode&utm_medium=feed)

Understanding distributed systems made blockchain much easier for me to understand.

7 min read · [rummansystems.hashnode.dev](https://rummansystems.hashnode.dev/blockchain-meets-distributed-systems-the-similarities-most-engineers-overlook?utm_source=hashnode&utm_medium=feed)

[Jun 7](https://hashnode.com/posts/blockchain-meets-distributed-systems-the-similarities-most-engineers-overlook/6a257c9958a6f041dfffe77a)

### [Designing a Resilient Order Fulfillment Architecture with Saga Pattern, RabbitMQ, Redis, and SQL Server](https://rummansystems.hashnode.dev/designing-a-resilient-order-fulfillment-architecture-with-saga-pattern-rabbitmq-redis-and-sql-server?utm_source=hashnode&utm_medium=feed)

Handling retries, idempotency, dead-letter queues, and eventual consistency in distributed order processing systems.

6 min read · [rummansystems.hashnode.dev](https://rummansystems.hashnode.dev/designing-a-resilient-order-fulfillment-architecture-with-saga-pattern-rabbitmq-redis-and-sql-server?utm_source=hashnode&utm_medium=feed)

[Jun 2](https://hashnode.com/posts/designing-a-resilient-order-fulfillment-architecture-with-saga-pattern-rabbitmq-redis-and-sql-server/6a1ebe0106c913b6fc3ada21)