Niranjan Rajendran
Software engineer · India · niranjan.io
Vol. X · No. 04 · Apr. MMXXVI
Section I
From the Notebook
Recent Writing
XII.

Drawing the map

We wanted an agent to map a web application so the next agent could write tests against it. The transcript was the wrong shape for that, so we put the graph where it belongs and the agents around it.

Oct 2025
XI.

An Operator of our own

OpenAI shipped Operator in January. We built a smaller one inside Mockingjay, using the accessibility tree where we can and falling back to vision when it comes up empty.

Apr 2025
X.

Letting GPT drive

We let GPT-4 pick selectors and run actions on a real page during a test. The demo went great. Then we met a virtualized list.

Jan 2024
IX.

Behind on AI

Why we shipped a GPT-4 feature on a weekend a few months back, and the prompt I'm still not proud of.

Jul 2023
VIII.

When the queue became a bus

Why we moved off BullMQ to RedPanda once a Go service had to consume from the bus, and the part that was just curiosity.

Mar 2023
VII.

Owning the browser

Why Mockingjay runs its own browsers in containers instead of shipping a Chrome extension, and what that costs.

Oct 2022
VI.

An honest accounting

A side project I stopped maintaining, why it kept growing anyway, and an Oracle trademark notice somewhere in the middle.

Aug 2022
V.

A fake fight

Recorder vs code tests, for automation engineers who already think one side is obviously right.

Jun 2022
IV.

A bet against test code

Why e2e test codebases rot, and the founding bet behind Mockingjay.

Jan 2022
III.

Accidentally a DevOps engineer

Inheriting an AWS account at a small fintech after the vendor was fired, with no handover and no AWS on my resume.

Jun 2021
II.

Patching JaDX

How I shipped JaDX inside an Android app by rewriting two of its methods at build time, without forking it.

Dec 2018
I.

A summer of lab notes

Looking back at a run of GSoC blog posts I wrote in 2016, and realizing they were something other than what I thought they were.

Jul 2017
Section IV
Correspondence
About

Niranjan Rajendran. Software engineer, ten years in, based in India. Currently co-founding Vulneron, building secure distributed systems.

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