Clear, practical essays on how real software gets designed, breaks, and ships — the failure modes I've run into, the trade-offs that turned out to matter, and the patterns that hold up in production.
A trace is a tree of spans stitched together by a context that has to ride along every hop. The traces that break almost always break at a boundary where nobody propagated the headers. Here is the model.
A session is a pointer to server state; a JWT is the state itself, signed. That single difference decides revocation, scaling, and where your security holes live. The trade-off, honestly told.
A VPC is just a CIDR block, a subnet is an AZ plus a slice of it, and "public" is a fact about a route table — not a checkbox. Here is the mental model that makes connectivity bugs obvious.
Readiness gates traffic, liveness restarts containers, startup protects slow boots — and wiring them up the same way is how a slow dependency turns into a restart loop. The differences that matter.
A test that passes on retry is not fixed — it's lying. The five real causes of flakiness, how to diagnose each one, and why auto-retry is a last resort, not a strategy.
Request memoization, the Data Cache, the Full Route Cache, and the Router Cache — what each layer stores, when it invalidates, and which one is serving you stale data right now.
localhost inside a container is the container, not your host — and that one fact explains most Docker networking confusion. A tour of bridge, host, none, and user-defined networks.
CORS is a browser-enforced rule about who may READ a cross-origin response — not a server firewall. Understanding that flips most CORS errors from mysterious to obvious.
A type annotation checks a value but throws away what it knows about it. `satisfies` checks against a type while keeping the narrow, literal type the value actually has.
Each topic page collects every article on that subject.