design patterns that compose the concrete pieces documented elsewhere — queues, delivery semantics, cursors, batch/serving splits. the layer above any specific database, language, or protocol.

the boundary against its neighbours:

storage/ and protocols/ — concrete systems (redis, sqlite, turso, turbopuffer, atproto, MCP)
data-structures/ — implementation tradeoffs in reusable structures
languages/ — language idioms (python, zig)
operations/ — running and shipping what you built
systems/ — the patterns that compose those things

if a note is mostly about what to do when something is already deployed and misbehaving, it belongs in operations/.

topics #

background-tasks — the celery→sidekiq→arq→docket lineage, why redis streams won over lists, perpetuals, scheduling future work (streams mechanics live in storage/redis/streams)
at-least-once-forwarder — outbox, ack-after-durable-commit, and a cursor pinned to min(inflight); why ack-on-receipt plus shedding is silent loss
serving-from-snapshots — build offline, verify against a manifest, adopt atomically; the overlay is authoritative, and batch cadence sets the freshness floor
change-timestamps — "when we last wrote" and "when the content last changed" are different columns; pinning the wrong one turns a correctness gate into a measurement of write traffic
watermark-semantics — one cursor, one meaning; the cost of a gate scales with the quantum of the thing it waits on
publish-then-free — intent before bytes, one atomic publish, abandon-commit-before-delete, tombstones re-swept; the same shape as a CoW B+ tree's alternating superblocks and free list
prior-art-encodes-someone-elses-constraints — a mature schema's complexity is evidence of its constraints, not of its correctness for you; take the primitives, leave the envelope
interface-design — start from the next action; language, decoration, simulated objects, long-running work, editing generated artifacts
interface-symbols — when a glyph helps and when a literal name is clearer; separators, controls, identity at small sizes
ios-interfaces — native structure with distinctive content, colour as a role, large text, verifying the native boundary
interactive-data-interfaces — spatial budgets, selection semantics, causal motion, stable updates and verification boundaries
simulated-pressure-ink — streaming perfect-freehand: speed relative to brush size, speed-scaled easing, time-normalized; stamp circles so the renderer cannot gap