Problems

Each problem is a small multi-file project with seeded bugs (or a missing feature), visible tests and hidden tests. Pick one, fix it, and submit. Problems marked Sign in need a free account.

• 20

  20Subscription Renewal Billing

  Subscription renewal billing (implement prorationCharge; anchors, retries, transitions)

  C++HardFeature60 min

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• 30

  30Refund Processing API

  Refund processing REST API (implement split; idempotency order, money parsing, window, reasons)

  Java · Spring BootHardFeature60 min

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