Full stack Developer familiar with Third-Party API & Checkout Integrations

Less than 1 month, Less than 30 hrs/week United States only Here's a revised version, generalized to e-commerce/API integration skills rather than naming the specific vendor: --- **Title:** API Integration Developer – Custom Checkout Build for Ticketing Platform **Description:** We're rebuilding our ticketing site (TicketIQ) with a custom checkout flow that integrates directly with a third-party ticketing/inventory API. This is a partner-level API integration — not a hosted checkout redirect — meaning you'll be building our own checkout UI and hitting a partner's order API directly for catalog sync, order placement, and webhook-driven updates. **What you'll be doing:** - Integrating with a third-party REST API for catalog/inventory data and order placement - Building webhook handlers for order confirmations, cancellations, and inventory sync events (must be idempotent — safely handle duplicate/out-of-order events) - Building or integrating a checkout flow, including payment handling considerations (tokenized card data, PCI scope) - Handling edge cases: failed payments, oversold inventory, race conditions - Working directly with a partner platform's technical docs/support to resolve integration questions **Required experience:** - Strong backend API integration experience with e-commerce or marketplace platforms (REST APIs, auth handling, rate limits) - Experience with webhook-based architectures and idempotent event processing - Experience with payment/checkout flows and understanding of PCI scope - Comfortable working with third-party documentation that may be incomplete — able to test against a sandbox and reverse-engineer behavior when needed **Nice to have:** - Experience with ticketing, event, or inventory-based marketplace platforms specifically - Experience using AI coding tools (Claude Code or similar) to accelerate development **Engagement structure:** We're planning to structure this in phases — discovery/architecture, build, then QA — since some of the timeline depends on a partner platform's response time for API credentials and sandbox access. Please share relevant past project examples, especially ones involving third-party API integrations or payment flows