Ahmet Zeybek

A major version upgrade with a write pause measured in seconds, not an outage measured in hours.

A working x402 paywall on a Next.js blog, from the 402 header to the settled USDC: what the protocol really sends, which facilitators settle on mainnet, the three things that break in a browser and the signed cookie plus one line of JavaScript that fix th…

If you have worked on a distributed system for long enough, you have felt the particular cold sweat of the dual write.

The pitch for an on-call agent is obvious and every vendor is making it: an alert fires at 3am, the agent reads the runbook, checks the dashboards, finds the cause, and either fixes it or wakes a human with a diagnosis instead of a pager message.

The first Shai-Hulud in September 2025 felt like an event.

"Just use Postgres" has been a slogan for a decade and it has always been slightly annoying, because it is usually said by someone who has not run the thing under load and is repeating it as a personality.

The product was real.

For fifteen years the JavaScript toolchain was written in JavaScript.

The number everyone quotes is 10x.

The take-home was a small service: read a CSV of transactions, apply some rules, expose two endpoints, write tests.

The phrase "context engineering" started showing up in job titles this year, which is usually the sign that a thing has become real and also that it has become vague.

In January about a fifth of the pull requests on our main service were opened by a coding agent, usually with a person driving it.

The feature was a summary at the top of every long thread in a customer's inbox.

Every version of Next.js since 13 has had a caching story that somebody was angry about.

I spent a chunk of the spring looking at how agents were wired into companies' systems, for three clients, in three industries.

In February I made a list of everything in my daily workflow that called a hosted model.

The support triage agent had a bug for a month and nobody could find it.

In March the monthly cost of logs, traces and metrics for our main API passed the cost of the machines it runs on.

I connected eleven MCP servers to a coding agent in February.

The argument has been running since about 2012.

Two years ago the runtime question was easy to dismiss.

In May 2025 a researcher at Invariant Labs showed that a free GitHub account and one issue in a public repository were enough to pull private repository contents, and the developer's own data, out of an agent running Claude with the GitHub MCP server.

Here is how I used to build an LLM feature.

The assistant sat on top of about 9,000 internal documents: runbooks, design docs, meeting notes, a wiki that had been migrated twice.

For fifteen years the answer to "why is my Python threaded code not faster" was one word.

There is a category of React code that exists only to stop React from doing work it would otherwise do. useMemo around a derived array. useCallback around a handler that gets passed to a memoised child.