The Havala integration in the order you have to do it: credentials, request signing, the invoice lifecycle, webhooks, testnets, launch.
Create a merchant account, take your merchant point credentials, and make your first signed request.
How the canonical string is assembled and signed with HMAC-SHA256, including the idempotency line that only write methods carry.
The full invoice lifecycle: create an invoice, check it out onto a chain, hand the buyer a deposit address, watch it confirm.
Receive payment.completed, verify X-Webhook-Signature against the raw body, stay idempotent under duplicate delivery, and reconcile what never arrives.
Which networks and assets Havala settles, how many confirmations each needs, and how amounts are represented on the wire.
How the buyer-facing payment page works, what the public checkout API exposes, and when building your own is worth it.
Run the whole flow without real money: TEST-mode invoices, testnet selectors, faucet funds, and an end-to-end script.
Account verification, production credentials, webhook hardening, and the checklist to clear before your first live invoice.
Point Claude, Cursor or ChatGPT at the Havala docs MCP server, and build against llms.txt.
The API reference carries every endpoint with its parameters, headers, signature pattern and a response body taken from the running API.
View API Reference