Hanzalah Waheed

Trying to understand how things work

my story so far

Two years ago I joined StockInsights.ai. I am now a founding engineer there, and I own most of the features on the primary web app. Underneath them runs a RAG pipeline I built that reads 25,000+ SEC and earnings filings a month, so analysts do not have to. I cut the infra bill by 80% and shipped the first recurring API revenue the company ever booked.

Open source is where I learned most of this, so I still send patches whenever the day leaves room. Some of that work is below.

my work

Jun 2026 – Aug 2026

Google Summer of Code 2026 Contributor — C2SI

I build DataLoom, an open-source, browser-based data wrangling tool, for the Ceylon Computer Science Institute. I started by setting up the transformation and feature registries the app now extends through, which made every later feature cheap to add: multi-format ingest (TSV, JSON, XLSX, Parquet), data profiling, quality assessment, charts, formula columns, reusable transformation pipelines, and a tabbed workspace layout. I also co-authored the authentication layer and am migrating the frontend to TypeScript.

Python · FastAPI · pandas · PostgreSQL · React · TypeScript · Docker

Aug 2024 – Present

Founding Software Engineer — StockInsights AI

I build the AI layer of an equity research platform: a RAG pipeline that auto-summarizes 25,000+ SEC and earnings filings a month, a multi-session AI chat system, and the frontend on top of both. Along the way I've migrated our full-text search off MongoDB Atlas, cut our Vercel bill ~80% by tracking down scraper traffic, and shipped the company's first recurring API revenue with Stripe metered billing.

Python · TypeScript · Next.js · PostgreSQL · pgvector · AWS · Docker

open source

the grind, mapped

my builds

prfrd
A performance-review engine where two agents argue. An advocate and an examiner build opposing, evidence-backed cases from an engineer's quarterly signals, an arbiter rules on them, and the full debate transcript is persisted to Postgres so every verdict can be audited. Weekly GitHub and Slack activity is normalized and rolled up into the monthly and quarterly evidence that grounds each claim, then surfaced as manager dashboards with team KPI rollups, risk flags for after-hours load and blockers, and per-engineer drill-downs.
Next.js · Vercel AI SDK · TypeScript · PostgreSQL · Drizzle · OpenAI Codex
Repository
A/B Image Generator
An application that helps you club together multiple images and then generate an A/B image for you, that you can post anywhere to A/B test your ideas. Launched on Peerlist, where it reached the top 30 on the leaderboard, and fully open-sourced.
Next.js · Tailwind CSS · TypeScript
Repository
Product Owl
A web app that tracks your favourite Amazon products and notifies you when they hit their lowest price, using scheduled web scraping.
Next.js · Tailwind CSS · TypeScript · PostgreSQL · Web Scraping
Repository

Archive (2 earlier projects)

Imagine Text
An image-to-text extractor built on Tesseract.js, running OCR client-side with Cloudinary handling uploads.
Next.js · Tailwind CSS · TypeScript · TesseractJS · Cloudinary
Repository
News Nation
A headlines aggregator for India's top current affairs stories, and one of the first things I ever built, back in 2020.
HTML · CSS · JavaScript
Repository

tools of the trade

Python

PostgreSQL

MongoDB

AWS

Docker

Git

Next.js

JavaScript

Python

PostgreSQL

MongoDB

AWS

Docker

Git

Next.js

JavaScript

TypeScript

Shadcn

Zustand

Tanstack

HTML

CSS

React

Node.js

Tailwind

Zod

Drizzle

tRPC

TypeScript

Shadcn

Zustand

Tanstack

HTML

CSS

React

Node.js

Tailwind

Zod

Drizzle

tRPC

writing

I mostly write about tech and some personal thoughts on stuff I read.

View all

Jul 14, 20268 min read

Halfway through GSoC: Building DataLoom

This blog post is about the progress we've made at DataLoom over the past month and a half.

Jun 01, 20265 min read

Doomscrolling Github, Contributing to OSS and GSoC

Hanzalah's views on Open Source Software and contributing to OSS in the age of AI and coding harnesses. And how to participate in Google Summer of Code.

Feb 02, 20264 min read

Dissecting Vercel’s React Best Practices (Part 2): Bundle Size Optimizations

I'm looking into another best practice considered **CRITICAL** to improve performance when building React apps: **Bundle Size Optimization**.

Jan 25, 20266 min read

Dissecting Vercel’s React Best Practices (Part 1): Eliminating Async Waterfalls

In this blog post, I’ve discussed the **first and most critical category** from the skill: **Eliminating Waterfalls**. It’s one of the highest-leverage optimizations because sequential async work can silently add hundreds of milliseconds to your page load and API response times.

Jan 18, 20266 min read

Why Updating Data in Postgres Is More Expensive Than You Think

A real-world case study on updating multi-million row Postgres tables. Covers MVCC, TOAST, GIN indexes, and why rebuilding tables can be cheaper than updating them in place.

Bookery

I love reading. Here are some of my favorite books.

Tech

Designing Data-Intensive Applications

Martin Kleppmann

4/ 5

Details