01Challenge

The client needed a platform where many sellers trade under one brand: with product moderation, flexible commissions, promotions, returns and payments through popular Kazakhstan payment systems — and with correct payment handling even when banks resend notifications.

02Solution

• Buyer, seller and administrator dashboards; product moderation and bulk approval
• An order state machine, returns and three invoice types
• A hierarchical commission engine, five types of promotion rules and promo codes
• Payment gateways with webhook deduplication and idempotent processing
• Full-text search, CSV product import and export, buyer-seller chat
• A PWA with push notifications and the tenge as the base currency

03Results

• A payment is never processed twice, even when the bank repeats a notification
• Business logic lives in 50+ services, which makes it easy to evolve and test
• An app-like mobile experience without publishing to app stores
• Admin panel, reports and notifications are ready