NineFifteenAM

Building in public

I'm building an algo trading bot in public. Every mistake included.

Three years of trading, one year of writing code that trades for me, and a long list of expensive lessons. I write down what works, what broke, and what it cost me — so you can skip a few of my mistakes.

193
days in public
6
posts written
—
readers on email
31
bugs documented

The Saturday letter

One email a week: what I built, what broke, and the lesson I'd pay money to have learned earlier.

Free. Unsubscribe anytime. No tips, no spam.

Mistakes that cost me

The ₹40,000 bug I shipped on a Friday

A missing check turned one rejected order into eleven retries in nine seconds. The code path, the logs, and the guard that now makes it impossible.

18 Sept 20262 min read
Best practices

Nine checks before your bot touches real money

The pre-live checklist I wish someone had handed me: paper-live parity, kill switches, config hashes, and the failure I only caught on the eighth check.

15 Sept 20261 min read
The journey

Month 6: the strategy worked, the plumbing didn't

Backtests looked fine, live results didn't match, and the gap had nothing to do with the strategy. What I found when I replayed real order books.

11 Sept 20261 min read

Latest posts

All posts →
26 Sept 2026
Why my backtest liedOne sentence that would make someone click this in search results.
The journey
18 Sept 2026
The ₹40,000 bug I shipped on a FridayA missing check turned one rejected order into eleven retries in nine seconds. The code path, the logs, and the guard that now makes it impossible.
Mistakes that cost me
16 Sept 2026
Reading a DRHP in 30 minutes: my checklistThe eight sections I read first in an IPO prospectus, the ratios I compute, and the things that make me close the document.
Market notes
15 Sept 2026
Nine checks before your bot touches real moneyThe pre-live checklist I wish someone had handed me: paper-live parity, kill switches, config hashes, and the failure I only caught on the eighth check.
Best practices
11 Sept 2026
Month 6: the strategy worked, the plumbing didn'tBacktests looked fine, live results didn't match, and the gap had nothing to do with the strategy. What I found when I replayed real order books.
The journey

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All guides →
Guides

Algo trading in India: the rules, the cost, and what to do first

What the law requires of a retail algo trader in India, what a system costs to run after the April 2026 STT change, and the order to build it in.

26 Sept 20269 min read

What this site is

The engineering behind a live algorithmic trading system in India: the build, the mistakes, what they cost, and how the rules actually work. No tips, no calls, no returns — read the about page for exactly what I do and don't publish.