{"product_id":"n8n-send21-crypto-invoice-payments-email-pay-links","title":"n8n Send21 Crypto Invoice Payments: Email Pay Links","description":"\u003ch3\u003eGet paid in stablecoins or Bitcoin—automatically—by sending Send21 crypto payment links from n8n\u003c\/h3\u003e\n\u003cp\u003eThis n8n workflow turns your invoice details (client, email, amount, currency) into a \u003cstrong\u003eSend21 pay link\u003c\/strong\u003e, emails it to your client, and then \u003cstrong\u003emarks the invoice paid only after Send21 confirms payment via a signed webhook\u003c\/strong\u003e. No manual chasing, no holding funds—your client pays from their own wallet.\u003c\/p\u003e\n\n\u003ch3\u003eWhat this workflow does\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCollect invoice input:\u003c\/strong\u003e An n8n \u003cem\u003eform\u003c\/em\u003e or \u003cem\u003eJSON webhook\u003c\/em\u003e provides \u003cem\u003eclient\u003c\/em\u003e, \u003cem\u003eemail\u003c\/em\u003e, \u003cem\u003eamount\u003c\/em\u003e, and \u003cem\u003ecurrency\u003c\/em\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCreate a Send21 payment link:\u003c\/strong\u003e The workflow generates a Send21 pay link using \u003cstrong\u003eUSDC\/USDT on Solana\u003c\/strong\u003e, \u003cstrong\u003eUSDC\/EURC on Base\u003c\/strong\u003e, or \u003cstrong\u003eBTC over Lightning\u003c\/strong\u003e. The invoice number is the \u003cstrong\u003eorder id\u003c\/strong\u003e, and an \u003cstrong\u003eidempotency key\u003c\/strong\u003e ensures retries return the same link.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEmail the pay link:\u003c\/strong\u003e Your client receives the payment link via email.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVerify payment securely:\u003c\/strong\u003e When paid, Send21 sends a \u003cstrong\u003esigned webhook\u003c\/strong\u003e. The workflow uses n8n’s \u003cstrong\u003eCrypto\u003c\/strong\u003e node to validate the \u003cstrong\u003eV2 signature over the raw body\u003c\/strong\u003e, rejects deliveries older than \u003cstrong\u003e5 minutes\u003c\/strong\u003e, ignores repeated delivery ids, and matches \u003cstrong\u003eorder, amount, and currency\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eUpdate invoice status:\u003c\/strong\u003e The invoice is marked paid and a receipt is emailed. Payments with a different amount are flagged and never accepted on their own.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUse cases\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eFreelancers and agencies sending crypto invoices in \u003cstrong\u003eEUR, USD\u003c\/strong\u003e, or other supported currencies\u003c\/li\u003e\n  \u003cli\u003eSaaS operators automating “invoice paid” status without manual reconciliation\u003c\/li\u003e\n  \u003cli\u003eTeams that want customers to pay from their own wallet while Send21 handles the crypto transfer\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003en8n nodes \/ logic:\u003c\/strong\u003e if, set, code, form, crypto, switch\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExternal services:\u003c\/strong\u003e Send21 API + SMTP (for emailing pay links and receipts)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSecurity:\u003c\/strong\u003e Bearer Auth for Send21 API key, webhook secret stored in a \u003cstrong\u003eCrypto credential\u003c\/strong\u003e, signature validation with raw-body V2 signature checks\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSetup steps:\u003c\/strong\u003e Add credentials, enter approved receiving addresses in the Settings node, run \u003cem\u003eRegister webhook (run once)\u003c\/em\u003e, and store the returned secret\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"N8N Commerce","offers":[{"title":"Default Title","offer_id":46326540337331,"sku":"N8N-21534","price":41.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0749\/6279\/6723\/files\/4Xs-H8mjdaASEN2Rf0U5B_GblNEcKh.png?v=1793352197","url":"https:\/\/buyflowscripts.com\/products\/n8n-send21-crypto-invoice-payments-email-pay-links","provider":"N8N Commerce","version":"1.0","type":"link"}