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on call

Take the pager

An incident simulator, a database of my work you can query, and your own session measured as you read. All of it runs in your browser and nothing leaves it.

01 · the shift

One shift, five pages

The failure modes are ones I've been paged for: an OOMKilled JVM, a poison message stuck on a Kafka partition, an ArgoCD reconciler quietly undoing someone's manual scale. The service names are made up. Reading the evidence costs a little error budget and guessing costs a lot. It takes about five minutes.

  • When the spike starts at a deploy boundary, stop reading logs and start reading the deploy history.
  • Latency that hits every service at once is rarely in any of them. Check the shared dependencies.

02 · query

Ask the database

A SQLite database of my work, compiled to WebAssembly and running in your tab. Pick a question, read the SQL that answers it, then edit it and run your own. The box is guarded by the same validator that refuses model-generated SQL in Clarity.

ask · devlinops.com

ask something

the query that answers it

Questions are mine. Database, query and result are real, and nothing leaves your browser.

03 · measure

Your session, measured live

The same numbers I'd put on a dashboard, taken from this page as you read it. Each one says what it means and what would count as bad.

TTFB · time to first byte

How long the server took to start answering you.

not measurable here

FCP · first contentful paint

How long before anything at all appeared on screen.

not measurable here

LCP · largest contentful paint

When the main content finished rendering.

not measurable here

CLS · cumulative layout shift

How much the page jumped around while loading. 0 is perfectly still.

not measurable here

Measured in your browser on this visit. Thresholds are the Core Web Vitals definitions. The site is static files, so a slow first byte means a long route to you.

the build serving you this page

commit855a033branchmainshipped5 Sept 2026sourcegithub.com/Jacko10101/website