Mechanism, not vocabulary
Deep dives
Most interview answers are one layer thick, which is why the third follow-up ends them. These 7 pieces go down to the mechanism — what Postgres does between parsing your query and returning a row, what CPython does with an integer, what the browser does between HTML bytes and a painted pixel. You will not be asked to recite any of it. You will be asked something whose answer depends on it.
- The network path of one request8 sections
DNS, TCP, TLS, HTTP/2 and /3, proxies, keepalive and connection pools — why timeouts, retries and p99 behave the way they do.
Backend · staff · 10 min read
- What a container actually is7 sections
Namespaces, cgroups, overlay filesystems, capabilities and seccomp — and why "it works on my machine" still happens.
DevOps & Cloud · staff · 9 min read
- From HTML bytes to a painted pixel9 sections
Parsing, style, layout, paint, composite — plus the main thread, the compositor, and exactly where jank comes from.
Frontend · staff · 9 min read
- How V8 runs your JavaScript8 sections
Parsing, Ignition and TurboFan, hidden classes and inline caches, deoptimisation, and the generational garbage collector.
JavaScript · staff · 9 min read
- How CPython actually runs your code9 sections
Objects, refcounts, the GIL implementation, bytecode and frames, the memory allocator, and what 3.11-3.13 changed.
Python · staff · 10 min read
- What Postgres does with your query10 sections
Parse, rewrite, plan, execute — plus buffers, WAL, MVCC, visibility and locks. The layer beneath every "add an index" answer.
SQL · staff · 14 min read
- Replication, consensus & the impossibility results8 sections
How Raft actually works, what quorums buy you, why FLP and CAP constrain everything, and how real databases replicate.
System Design · staff · 10 min read