How it works - WalletConnect Pay Docs
The payment lifecycle
Whatever UI you build, the runtime moves a payment through the same stages. Your job is to render each stage and call the matching action.
Load the payment
The buyer arrives with a payment ID (from a QR code, link, or your checkout). The runtime fetches the payment intent — amount, merchant, accepted tokens.
Connect a wallet
The buyer connects a wallet through the WalletProvider seam. The runtime reads their accounts across the supported networks.
Fetch payment options
Given the connected accounts, the Engine returns the concrete ways to pay — token, network, amount, fees, and whether compliance data is required.
Select & build
The buyer picks an option. The runtime builds the transaction(s) and the exact wallet-RPC actions to sign.
Sign
The Signer drives the wallet through the required signatures (e.g. a permit + the payment).
Confirm & settle
Signed results are submitted to confirm the payment. The runtime then polls status until the payment succeeds, fails, or expires.
How it fits together
The Headless SDK follows a headless runtime + host model. The payment flow lives entirely in the SDK; your application is the host that consumes it. The runtime reaches the outside world only through five injectable seams — so you can swap in your own transport, wallet, timing, and analytics, and reuse the exact same payment machine.
The five seams the runtime depends on:
| Seam | What it abstracts | Provided by |
|---|---|---|
Transport |
Engine HTTP calls | pay-core createHttpTransport → your server route |
WalletProvider |
connect / accounts / provider / switch | pay-appkit, or your own wallet integration |
Signer |
sign a payment option’s wallet-RPC actions | pay-appkit createAppKitSigner — one call (wraps pay-state’s signing; drop to its raw strategies only for a custom, non-AppKit wallet) |
Clock |
intervals + page visibility (for polling) | browser timers (the SDK ships a default) |
Telemetry |
analytics breadcrumbs | your analytics pipeline (optional) |
@walletconnect/pay-state ships browser-ready Clock and Telemetry defaults (browserClock, noopTelemetry). In practice, a React/Next.js gateway wires just the Transport (pointed at your server route); the WalletProvider and Signer come ready-made from pay-appkit (<PayAppKitProvider> + createAppKitSigner), and it reuses browserClock for the rest. Telemetry is optional.
The Engine API key never reaches the browser
WalletConnect Pay’s Engine API is authenticated with a secret API key that must stay server-side. The SDK enforces this split: the browser talks to your server, and your server talks to the Engine.
pay-core exposes two entry points for exactly this: createHttpTransport for the browser (talks to your server) and createEngineClient (imported from @walletconnect/pay-core/server) which holds the API key and talks to the Engine. In a Next.js app, your Route Handler sits in the middle.
Next steps
Implementation
Build a complete checkout in React / Next.js, step by step.
Packages Reference
The public API of pay-core, pay-state, pay-react, and pay-appkit.