Core Building Blocks
IDs, KV stores, locks, search, geo, counters, feeds, schedulers, and payments.
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Unique ID Generation
UUIDv4, UUIDv7, ULID, and Snowflake IDs, index locality, clock rollback, and hiding sequential IDs.
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Distributed Key-Value Stores
Partitioning, replication, storage engines, versioning, conflict resolution, and failure detection.
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Distributed Locks & Coordination
Lease-based locks, Redlock, fencing tokens, ZooKeeper, and leader election for singleton jobs.
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Search, Ranking & Autocomplete
Inverted indexes, analyzers, TF-IDF and BM25, index sharding, near-real-time indexing, typeahead, and hybrid search.
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Geospatial Indexing & Proximity
Geohash, quadtrees, S2, and H3, nearby queries, moving objects, and ride matching.
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Counters, Top-K & Sketches
Distributed counters, HyperLogLog, count-min sketch, quantile sketches, and exact vs approximate counts.
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Feeds, Timelines & Notifications
Timeline assembly, ranking, pagination over changing lists, notification fan-out, preferences, and digests.
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Schedulers, Cron & Job Systems
Distributed cron, delayed jobs, timer wheels, idempotent retries, priority and fairness, and workflow engines.
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Payments, Ledgers & Money Movement
Double-entry ledgers, idempotent charges, balance races, reconciliation, and webhook retries.
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