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Challenge

Charge once when payment acknowledgements drop

The gateway retries payments. A network glitch drops the response after the ledger write already succeeded.

The retry charges twice. Wire the idempotency store so retries return the original result.

  • Goodput

    ≥ 99.0%

    every seed

  • Budget

    $400/mo

    ★★ at ≤ $320

  • Traffic

    100 req/s (constant)

    deadline 40 ms

  • Failure ·

    partition

    at t = 10.6 ms

★★★ adds 1 variant failure timeline.