rosneri / writing
field notes — the log Vol. 4 · 10 posts · Tel Aviv · updated Mar 2026
$ ls ~/writing --all --sort=recent

Writing

Notes on payments infrastructure, distributed systems, and the startup that didn't make it — plus the dev tools and ~30 books a year that fund the rest. Written down so I don't have to learn it twice.

10 posts
~9 min avg
6 topics
Latest Systems Mar 2026 · 11 min

Designing a dead-letter queue you can trust

In payments, the interesting question was never what happens when a message processes — it's what happens when it can't. Poison messages, replay safety, per-aggregate ordering, and schema drift, from the financial core at DoorLoop.

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Feb 2026 Engineering

Zero any, one year on

Twelve months of strict TypeScript with no escape hatches. What the compiler caught before code review did, and how the rule walked me into domain-driven design one rejected cast at a time.

8 min read
Jan 2026 Systems

Idempotency keys are a design input, not a retry hack

If processing an event twice can't equal processing it once, you don't have a queue — you have a liability. Where the key comes from, and why the check and the effect must commit together.

7 min read
Dec 2025 Systems

Stripe Treasury: embedded banking without becoming a bank

What it actually takes to move customer funds — accounts, fund flows, the reconciliation you don't see — and the failure modes that decide the architecture.

9 min read
Nov 2025 Startups

SpecBite: an honest postmortem

My failed startup, with the parts I'm not proud of left in. The engineering shipped; the business didn't. Here's the difference, in detail.

14 min read
Nov 2025 Books

I keep my reading list in git

~30 books a year, one commit at a time. Queue management, speed, retention, and what I do with the notes when a book is worth keeping.

4 min read
Oct 2025 Systems

Running K8s for a side project (don't)

I did it so you can read about it and choose a boring Postgres box on a single VM instead. A breakdown of what the complexity actually bought me.

9 min read
Sep 2025 Engineering

DDD for people who actually ship

Domain-driven design without the 500-page book. The three ideas I use every week and the rest I happily ignore.

12 min read
Aug 2025 Games

A LitRPG engine in TypeScript

Stats, progression curves, and generated encounters as plain data. Building a narrative game engine I can actually reason about — and test.

7 min read
Jul 2025 Dev tools

Building an MCP server in an afternoon

The Model Context Protocol is smaller than it looks. I shipped a working server between lunch and dinner — here's the whole shape of it.

6 min read