← CatZep/Engineering Guides/System Design
Autocomplete, proximity, dispatch, and tracking.
Learn the reason behind each component
4 independent guides. Each includes local concept explanations, a correctness contract, a worked failure trace, and a runnable Python learning model.
Read in this order: requirements → concepts → data flow → concurrency and failure behavior → sizing → worked example. Explain what can fail before choosing a technology.
4 guides
Turn messy carrier scans into a trustworthy shipment history and a reproducible current-state projection.
State machines and projections · Event time and watermarks · Deduplication · Optimistic concurrency and compare-and-set · Transactional outbox · ETA and uncertaintyFind nearby points by a conservative spatial covering, then refine and rank without missing boundary neighbors.
Geohash · Quadtree and adaptive spatial indexing · ETA and uncertainty · Inverted indexes and columnar storage · Cache-aside and invalidationUse approximate location candidates but one authoritative state transition for exclusive trip assignment.
Geohash · ETA and uncertainty · Optimistic concurrency and compare-and-set · Leases · State machines and projections · Transactional outboxServe ranked prefix completions from a normalized, versioned snapshot without traversing a huge subtree on each keystroke.
Trie and cached prefix top-k · Top-k candidate discovery · Cardinality · Cache-aside and invalidation · DAG schedulingNo guide matches. Try a broader concept such as replication or retries.
Download the Python concept models · Python 3.10+, no packages required.
Student clarity and correctness review · 19 October 2026