Start here for the current product surface: projects, API keys, payment event monitoring, incidents, alerts, and reprocess.
These docs cover the parts of SendPromptly your backend actually talks to: creating a project, authenticating requests, sending the two signals that make up the monitoring flow (receipt and result), and configuring the repair callback SendPromptly calls when your team clicks Reprocess. They assume you already have a Stripe or Shopify webhook handler in place — SendPromptly adds two HTTP calls to it, not a new integration layer or event router.
If you only read one page, read the Quickstart: it walks through instrumenting a single payment path end to end in about an afternoon. Come back to the reference pages below when you need the exact request shape, header requirements, or error code for a specific case.
Recommended path
If you are starting from the product workflow first rather than the API, read Post-Payment Failure Recovery before instrumenting your first handler — it explains the detection and repair model these reference pages assume.
For implementation background, see Stripe webhook idempotency, Stripe signature verification, and Shopify orders/paid troubleshooting.