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.

• 01

  01Returns Eligibility Service

  Return-policy rule engine + JSON parser

  C++MediumBug fix60 min
• 04

  04Marketplace Seller Payouts API

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

  Java · Spring BootMediumBug fix60 min
• 07

  07Service Latency Log Analyzer

  Service latency log analyzer (percentiles, error rates)

  C++MediumBug 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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• 15

  15Return Routing Engine

  Return routing engine (restock/vendor/liquidation/disposal, warehouse choice, batch retries)

  C++MediumBug fix60 min

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• 16

  16Catalog Cache Service

  Catalog LRU/TTL cache (read-through service, TTL policy, metrics)

  C++MediumBug fix60 min

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• 18

  18Fast Delivery Eligibility Checker

  Fast-delivery eligibility checker (JSON feed, longest-prefix regions, cutoffs, carts)

  C++MediumBug fix60 min

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• 25

  25Return Authorization API

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

  Java · Spring BootMediumBug fix60 min

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• 26

  26Shipment Tracking Events API

  Shipment tracking events REST API (pipe feed, duplicates, out-of-order scans, late flag)

  Java · Spring BootMediumBug fix60 min

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• 28

  28Warehouse Pick-Wave API

  Warehouse pick-wave REST API (wave packing, serpentine walk, pick-list totals)

  Java · Spring BootMediumBug fix60 min

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