No. 03April 22, 2026
My AI workflow, end to end
The actual tools and habits I use to fold AI into daily work, not the highlight reel.
1 min read
A founder's field notes
Notes on building companies, products & a life worth writing down.
I build things, get some of it wrong, and publish the lessons — so you can skip the expensive parts.
Latest from the notebook
All articles →No. 02February 3, 2026
How I think about decisions
A simple framework for telling reversible decisions from the ones that actually deserve a meeting.
1 min read
No. 01January 14, 2026
Hiring lessons from year one
What I got wrong about hiring in the first twelve months, and the checklist I use now.
1 min read
About the author
I'm Sunil Kumar — a founder who believes the most valuable thing a builder can leave behind isn't a pitch deck, it's a paper trail. This site is my permanent notebook: the operating principles I run on, the projects I've shipped and sunset, the books that rewired my thinking, and a public database of my failureswith the tuition fees itemized.
Nothing here is a highlight reel. The rule I write by:publish insights, not private thoughts — and never publish a lesson I haven't personally paid for.
From the workshop
Everything I've built →2022 — presentactive
Current Company
Building the thing I spend most of my working hours on. More on this soon.
2024shipped
Weekend Analytics Tool
A small SaaS tool I built and sold to a niche audience of freelancers to learn the full indie-hacker loop end to end.
2018 — 2020sunset
First Startup
My first real company. Wrong market, right lessons — see the [failures page](/failures) for the full post-mortem.
Paid in full — lessons from failures
Every mistake documented: what happened, why, and what it taught me.