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.

• 03

  03Fulfillment Inventory Reservation API

  Inventory reservation REST API (CSV stock load)

  Java · Spring BootEasyBug fix60 min
• 04

  04Marketplace Seller Payouts API

  Seller payout ledger REST API (CSV import, fees, auth)

  Java · Spring BootMediumBug fix60 min
• 08

  08Checkout Coupon Service

  Checkout coupon REST API (quote, redeem, limits)

  Java · Spring BootEasyBug fix60 min

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• 09

  09Order Lifecycle Service

  Order lifecycle REST API (state machine, ownership, cart parsing)

  Java · Spring BootMediumBug fix60 min

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• 10

  10Cart Promotion Pricing Engine

  Cart promotion pricing engine (implement price)

  Java · Spring BootMediumFeature60 min

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• 21

  21Gift Card Wallet API

  Gift card wallet REST API (codes, ownership, expiry, idempotent redemptions)

  Java · Spring BootEasyBug fix60 min
• 22

  22Dock Appointment Booking API

  Dock appointment booking REST API (door choice, half-open slots, validation)

  Java · Spring BootEasyBug fix60 min
• 23

  23Price Drop Alert API

  Price-drop alert REST API (alert limits, CSV price feed, triggers)

  Java · Spring BootEasyBug fix60 min
• 24

  24Review Helpfulness Votes API

  Review helpfulness votes REST API (implement rank; votes, burying, tie-breaks)

  Java · Spring BootEasyFeature60 min
• 25

  25Return Authorization API

  Return authorization (RMA) REST API (policy windows, restocking fees, lifecycle, ownership)

  Java · Spring BootMediumBug fix60 min

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