The design library
Building blocks, complete architectures, and variations worth comparing. Search by the problem you want to solve or a component you want to understand.
Classic designOfficial
Record every money movement as balanced, append-only entries, exactly once, with holds, payouts and reconciliation: one-hour boards for junior, senior and staff, with the theory behind them.
Classic designOfficial
Find restaurants that deliver to you, check out without double charges, time couriers to the kitchen and track them live: one-hour boards for junior, senior and staff, with the theory behind them.
Classic designOfficial
Buy the cheapest offer under a maximum price from 1,000 sellers: cached offers, coalesced quotes, a hold-order-capture saga, open requests: one-hour boards for junior, senior and staff, with the theory behind them.
Classic designOfficial
Ten charities, three days, $100 M: charge through a third-party processor exactly once, queue the broadcast spikes, keep live totals on sharded counters. One-hour boards for junior, senior and staff, with the theory behind them.
Classic designOfficial
Nights as counted inventory, holds that never double-book, search that knows availability, and payments that reconcile: one-hour boards for junior, senior and staff, with the theory behind them.
Classic designOfficial
Charge cards through the networks exactly once: idempotency keys, a card vault, timeouts as unknowns, signed webhooks, a double-entry ledger and reconciliation. One-hour boards for junior, senior and staff, with the theory behind them.
Building blockOfficial
The caller names the operation, the server stores the first response under that name, and a retry replays it instead of doing the work twice.