The journal

Working notes from
a live desk.

Market structure, risk arithmetic, and post-mortems when our own systems fail. Written by the people who build and run the thing — not by a content team.

Posts34
Post-mortems6
Since2024
Risk Featured

The drawdown you didn't budget for

Everyone quotes maximum drawdown as a depth. Depth is the easy half. The number that actually ends subscriptions is how long you spent underwater — and almost nobody publishes it.

AR Arunkumar Rangpariya · 11 Aug 2026 · 9 min read
Market structure

Why your backtest fills and your broker doesn't

A limit order at the touch is not a fill. What the queue actually does to a strategy that assumed otherwise.

RB Ravi Bharr · 4 Aug · 7 min
Post-mortem

41 minutes of stale ticks on 14 May

A feed handler held a socket open after the exchange stopped sending. Nobody's risk limits fired, because nothing looked wrong.

PN Priya Nandwani · 22 Jul · 12 min
Risk

Reading a pool record like an auditor

Nine places a published track record can flatter itself, and the field on our own record page that catches each one.

AR Arunkumar Rangpariya · 15 Jul · 11 min
Regulation

What SEBI's ODR rollout changes for advisory platforms

Online dispute resolution is now a real escalation rung. Here is what we had to rebuild to sit correctly beside it.

PN Priya Nandwani · 2 Jul · 8 min
Engineering

Kill switches that actually stop things

A brake that only stops new orders is not a brake. What ours cancels, what it cannot, and why we say so out loud.

SM Saurabh Mittal · 24 Jun · 6 min
Market structure

The cost of a 1% slippage assumption

Run the same pool through four cost models. Three of them turn a winning record into a losing one.

RB Ravi Bharr · 11 Jun · 9 min
Risk

Sharpe is not a safety rating

Two pools, identical Sharpe, wildly different ways of losing your money. Sortino and Calmar say what Sharpe won't.

AR Arunkumar Rangpariya · 30 May · 10 min
Post-mortem

We double-sent 74 orders. Here is the exact minute

An idempotency key that wasn't. Every affected account, what it cost, and what we paid back.

SM Saurabh Mittal · 18 May · 14 min
Engineering

Replaying six years of ticks in ninety seconds

How the backtest engine is laid out, why it is columnar, and the one shortcut we refuse to take.

RB Ravi Bharr · 3 May · 13 min

One note a week, on the Sunday before the open.

What changed on the platform, what broke, and one piece of market arithmetic worth knowing. No trading calls — we are not allowed to give them, and would not anyway.

Mockup — nothing was submitted.