playground
Things here that actually run
Three of them, and none is a mock-up: a database of my work you can query, your own session measured as you read, and a shift on the pager. Nothing leaves your browser.
01 · query
Ask the database
A real 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 something
the query that answers it
Questions are mine. Database, query and result are real, and nothing leaves your browser.
02 · 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.
How long the server took to start answering you.
not measurable here
How long before anything at all appeared on screen.
not measurable here
When the main content finished rendering.
not measurable here
How much the page jumped around while loading. 0 is perfectly still.
not measurable here
Measured in your browser, on this visit — not a screenshot of a good day. Thresholds are the Core Web Vitals definitions. This site ships as static files, so a slow first byte is the journey to you, not a server thinking.
03 · on call
Take the pager
One shift, five pages, drawn from failures I have actually been woken up for: an OOMKilled JVM, a poison message stuck on a Kafka partition, an ArgoCD reconciler quietly undoing someone's manual scale. Reading the evidence costs a little error budget and guessing costs a lot. It takes about five minutes.
the build serving you this page