FAQ

Five questions a developer or agent operator typically asks first. The full surface is in the documentation; this is the entry point.

Do I need an account?

No, not for the lodestone path. Sign an EIP-3009 payment authorization off-chain, attach it as a PAYMENT-SIGNATURE header, send a single POST /v1/envelopes request, and you get back a signing URL. No signup, no dashboard, no email confirmation.

If you want history reads later, the same wallet address can sign in via the wallet JWT path and see its own envelopes. If you want a single API key for many calls without per-request signing, sign up with Google or GitHub at app.verafirma.com and mint one. Both are optional layers on top of the per-call path.

How does x402 work?

The wallet signs an EIP-3009 transferWithAuthorization for the call’s exact amount, off-chain (no gas). The signature carries the wallet address, the recipient (the facilitator), the amount, a validity window, and a replay-protected nonce. The signature lands as a request header; the API verifies it, settles synchronously through the facilitator, and runs the wrapped operation. By the time the response returns, the wallet has been debited.

x402 is not EIP-191, SIWE, or personal_sign — those are for wallet-as-identity signin (the wallet JWT path), which is a different flow. See /concepts/x402 for the wire format.

What’s the price?

$0.10 per envelope. Pay per call — no minimum, no commitment. Refunded automatically on terminal failure (REJECTED, EXPIRED, CANCELLED) up to a per-envelope cap.

The full breakdown by payment mode is at /pricing.

Where’s the OpenAPI spec?

https://api.verafirma.com/openapi.json — full machine-readable surface.

The web-rendered version with audience-augmented metadata is at /api-reference. Generate a typed client from the JSON in your language of choice; the spec is OpenAPI 3.1.

Where’s the MCP endpoint?

https://api.verafirma.com/mcp — streamable-HTTP MCP server. Tools wrap the same handlers as the REST API; auth flows through the same modes (API key, x402, wallet JWT).

The current V1 tool set: verafirma.create_signing_request, verafirma.get_envelope_status, verafirma.list_envelopes, verafirma.register_webhook. The authoritative list is in the tools/list response from the endpoint. See /concepts/mcp for client config patterns.