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FIELD NOTES

A running library of concepts, patterns, and longer thoughts on technology and accessibility.

CONCEPT — SYSTEMS DESIGN

Idempotency & Delivery Semantics

At most once (may drop), at least once (may repeat), exactly once (never drop, never repeat) — the three delivery guarantees for messaging.

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CONCEPT — SYSTEMS DESIGN

Input, Output & Boundaries

The three things that matter most in any system's design: what comes in, what goes out, and the boundaries between them.