Project Overview
Developed and deployed a custom end-to-end payment integration for Prime Peptides LLC, a high-risk merchant on the Wix platform. Since traditional processors like Stripe and PayPal often restrict high-risk industries, I engineered a bridge between Wix E-commerce and the PsiFi/Simplex ecosystem. This solution allows customers to pay via Credit Card through a crypto-on-ramp seamlessly, ensuring business continuity in a restricted market.
Challenge
- Industry Restrictions: Traditional gateways were unavailable due to the nature of the products, requiring a non-standard, resilient payment architecture.
- Complex Checkout Requirements: The system needed to dynamically inject a 5% processing fee, handle Wix promo codes, and manage shipping costs within the API payload without breaking price checksums.
- Asynchronous Confirmations: Because the gateway uses a crypto on-ramp (Simplex/Banxa), payments take 15–20 minutes to verify on-chain. I had to ensure Wix would accurately update order statuses asynchronously without manual intervention or data loss.
Solution
I built a custom "Service Provider" integration using Wix Velo and Node.js. Key technical implementations included:
- Dynamic Payload Engineering: Built a logic engine to decompose the Wix Cart, calculate a 5% gateway fee, and reassemble it into PsiFi "Products" via API.
- Secure Webhook Architecture: Developed a backend listener (
_functions/psifiWebhook) using HMAC-SHA256 signature verification to ensure only legitimate payment signals from PsiFi could update the database. - Data Synchronization: Injected Wix Buyer metadata (Name, Email, Phone) and Order IDs into the gateway session to ensure the merchant's dashboard remained organized and searchable.
- Idempotency & Race Condition Protection: Implemented unique cryptographic hashes for every line item to prevent duplicate charges and ensure "Order Completion" only triggered once.
Result
The integration successfully allowed the merchant to go live and process credit card transactions securely. By automating the webhook-to-order flow, I reduced manual order management time by 100% and provided a professional checkout experience that mirrors standard credit card processors, despite the complex crypto-infrastructure running in the background.