License Kit cryptography
0.5%flat gateway fee
No custodymerchant wallet control
Testnetbefore mainnet review
Webhooksoperational records
Turn completed on-chain crypto payments into offline-verifiable ES256 software licenses.
XPayr License Kit binds software, SaaS, browser extension, and plugin entitlements to the payer wallet and signs short-lived ES256 JWT tokens verifiable via public JWKS.
Wallet-bound licensing means the customer pays once on-chain and proves ownership by signing a free challenge message from the same wallet. XPayr issues an ES256-signed JWT verifiable offline against https://xpayr.com/.well-known/jwks.json or @xpayr/extension-kit (v0.2.0).
01
Customer completes a non-custodial crypto payment for a licensed product.
02
XPayr records the wallet-bound entitlement tied to the product slug and plan.
03
Client app requests a wallet challenge and exchanges the signature for an ES256 JWT.
04
App verifies the JWT signature offline using /.well-known/jwks.json (/api/v1/licenses/jwks).
Who pays gas?
License verification and wallet message signing are 100% off-chain and require zero gas fees.
Operational limit
Licenses are bound to the wallet address that completed the purchase and follow the merchant configured plan duration.
FAQ
What problem does this XPayr flow solve?
Wallet-bound licensing means the customer pays once on-chain and proves ownership by signing a free challenge message from the same wallet. XPayr issues an ES256-signed JWT verifiable offline against https://xpayr.com/.well-known/jwks.json or @xpayr/extension-kit (v0.2.0).
Who pays gas or network fees?
License verification and wallet message signing are 100% off-chain and require zero gas fees.
What should merchants not assume?
Licenses are bound to the wallet address that completed the purchase and follow the merchant configured plan duration.
Verifiable Open-Source & AI Protocol Registry
Publicly auditable SDKs, cryptographic evidence envelopes, and MCP registries.
Official 21-Tool MCP Server
Registered as io.github.xpayrcom/xpayr-mcp-server on the Official Anthropic MCP Registry and published as @xpayr/mcp-server on NPM and ghcr.io/xpayrcom/xpayr-mcp-server:latest.
Merkle Payment Evidence & ES256 Tokens
Verify on-chain settlement envelopes with @xpayr/payment-evidence and offline-verifiable ES256 wallet licenses with @xpayr/extension-kit.
30 Open-Source Repositories & RFC 9116
Inspect all 20 REST API v1 schemas interactively at api-docs.xpayr.com, review our 30 repositories at github.com/xpayrcom, and check /.well-known/security.txt & /.well-known/jwks.json.
Need to prove the flow before production?
Use testnet checkout, API docs, webhook guides, and operational explainers before asking for mainnet activation.