Make one stablecoin payment flow safer to release in 24 hours.
I will turn one existing checkout, invoice, payment-link, or webhook path into a compact executable acceptance pack. The package focuses on the boundary where a provider says paid and your application decides whether to fulfill an order, activate access, or update a balance.
You receive:
- 8 provider-specific automated tests in TypeScript- Deterministic, sanitized payment and webhook fixtures- Exact amount, currency, recipient, and order-binding checks- Duplicate, delayed, malformed, and invalid-state cases- Exactly-once fulfillment coverage- A concise README with run instructions- A one-page findings and handoff note- One revision for the agreed payment path
Good fit for USDC or USDT checkout flows, hosted invoices and payment links, HMAC-signed webhooks, and Node.js or TypeScript backends that already have API documentation or sample sandbox events.
This gig covers one agreed payment path. It does not include a smart-contract audit, a full payment integration, production deployment, custody of funds, transaction signing, or handling production credentials.
I work only with public documentation, sandbox access, or sanitized samples. Never send private keys, seed phrases, production wallet credentials, or live signing secrets.