BTCPay Server Checkout Addon for Krikkit adds self-hosted crypto checkout to Krikkit. Point it at your BTCPay Server, send the buyer to that invoice, and unlock the pack when BTCPay reports InvoiceSettled. Krikkit is the Greenfield API client and the signed webhook handler. You run the BTCPay Server.

Checkout

• Dashboard path: Payment Methods, then BTCPay
• Server URL, Store ID, Greenfield API key, and webhook secret
• Webhook URL to paste into BTCPay, Store, Settings, Webhooks
• Subscribe to InvoiceSettled
• Test connection before the method goes live
• Secrets are encrypted at rest with the Krikkit app key

Before a pack unlocks

• The webhook signature is HMAC SHA-256 on the raw body, header BTCPay-Sig
• Krikkit fetches the invoice again from Greenfield and checks amount, currency, store, and metadata
• The server URL must be HTTPS. Private, metadata, and localhost targets are rejected
• Outbound calls re-check DNS and do not follow redirects
• The checkout host must match the server URL you saved

Requirements

• Krikkit 2.1.0 or newer
• PHP 8.3+ and MySQL, same stack as Krikkit
• Your own BTCPay Server, reachable over HTTPS
• A Greenfield API key that can create and read invoices for one store

On-chain refunds are processed in BTCPay Server. This addon installs under extensions/Btcpay and does not patch Krikkit core files.