Merchant Onboarding

Onboarding takes a merchant from “I want to accept stablecoins” to working API keys in under five minutes.

The flow

1. Sign in — email-OTP via the merchant dashboard.
2. Attach a wallet — SIWE (Sign-In With Ethereum) binds an EOA to the account. This wallet becomes the default settlement destination.
3. Create a project — each project has its own keys, webhook secret, and settlement preferences.
4. Issue API keys — keys are scoped per project: sk_test_* (sandbox) and sk_live_* (production).
5. Configure webhooks — point at your endpoint and store the webhook secret.

Authentication model

Credential	Lifetime	Scope	Where it lives
OTP code	10 minutes	One-time login	Email
Session JWT	24 hours	Dashboard actions	Browser, httpOnly cookie
sk_live_* / sk_test_*	Long-lived	Project	Your server, never the client
pmc_* publishable	Long-lived	Project, restricted	Safe to ship in client bundles

Server keys (sk_*) and publishable keys (pmc_*) are issued in pairs per project.

SIWE handshake

After OTP login, you’ll be prompted to sign a SIWE message to bind a wallet to the account:

example.com wants you to sign in with your Ethereum account:
0xabc...123

Sign in to StablecoinX as Merchant XYZ

URI: https://dashboard.stablecoinx.com
Version: 1
Chain ID: 1
Nonce: <server-generated>
Issued At: 2026-05-26T17:00:00Z

The bound wallet becomes the default settlement destination. You can override it per project or per session later.

Profile metadata

Configurable per project:

• Business name and logo (rendered in checkout, hosted on our CDN).
• Default settlement chain and asset.
• Webhook URL and secret.
• Refund policy displayed on the hosted redirect page.

API key scoping

Key prefix	Use	Allowed
sk_live_*	Server-side, production	Full project surface
sk_test_*	Server-side, sandbox	Full sandbox surface
pmc_*	Client-side	Create sessions only; origin-allowlisted

Rotate keys from the dashboard at any time. Old and new keys are both valid for a configurable grace window (default: 24h).

Next

• Quickstart — make your first API call.
• Session Payment — the primary product surface.
• Paymaster — sponsor gas for your users.