Modules
Elixir implementation of the Machine Payments Protocol (MPP).
Parse, format, and rank the Accept-Payment client-preference header.
Amount and decimal helpers for converting human-readable amounts to base units.
SHA-256 body digest computation and verification.
Payment challenge — the 402 response that tells a client what to pay.
Gates Accept-Payment header injection on outgoing HTTP requests.
Payment-aware MCP client orchestration.
Wraps multiple payment providers and dispatches to the first match.
Behaviour for client-side payment providers.
Built-in Stripe charge provider using Shared Payment Tokens (SPTs).
Built-in Tempo charge provider.
Payment-aware Req plugin.
Returned when payment-aware retry cannot complete a 402 challenge.
Transport-neutral challenge selection and ordering.
Behaviour for client-side transports that bridge a protocol response/request pair and the MPP payment flow.
HTTP implementation of MPP.Client.Transport over Req.
JSON-RPC implementation of MPP.Client.Transport for generic (non-MCP) RPC.
JSON-RPC implementation of MPP.Client.Transport for MCP.
WebSocket implementation of MPP.Client.Transport.
Reconnect and payment-retry policy for MPP-over-WebSocket.
Shared base64url→JSON token decoding for the wire-format modules
(MPP.Credential, MPP.Receipt, MPP.Methods.Tempo.SessionReceipt).
Payment credential — the client's response to a 402 challenge.
Decentralized identifier (DID) helpers for MPP credential sources.
Demo payment method — accepts a magic token for local testing.
Demo router for mix mpp.demo — serves a protected endpoint behind MPP.
Generates OpenAPI 3.1.0 discovery documents for MPP-enabled HTTP operations.
Parser and normalizer for the discovery specification's x-payment-info extension.
RFC 9457 Problem Details for MPP payment errors.
Expiration timestamp helpers for MPP challenges.
Parse and format the three MPP protocol wire-format headers.
Small internal hex-string helpers shared across the payment-method and wire-format modules.
Shared contract implemented by payment-intent schemas.
Charge intent request schema — the "Intent = Schema" half of MPP.
Session intent request schema — the "Intent = Schema" half of MPP for pay-as-you-go / metered sessions.
Shared recurring-subscription intent schema.
RFC 8785 JSON Canonicalization Scheme (JCS) — MPP subset.
MCP (Model Context Protocol) payment transport helpers.
Behaviour for pluggable payment method verification.
Generic EVM payment method — verifies on-chain ERC-20 or native ETH transfers.
EIP-3009 transferWithAuthorization credential for Circle USDC/EURC.
NEAR Intents charge method backed by the 1Click Swap API.
Verification helpers shared by the payment-method modules
(MPP.Methods.EVM, MPP.Methods.Tempo, MPP.Methods.Stripe,
MPP.Methods.Solana, MPP.Methods.NearIntents).
Solana payment method — verifies native SOL and SPL token charge payments.
Parse and match Solana payment instructions for MPP.Methods.Solana.
Stripe payment method for one-time charges and recurring subscriptions.
Stripe Billing activation for the shared subscription intent.
Tempo payment method — verifies payment via on-chain TIP-20 token transfer.
Sponsor (fee-payer) gas-economics policy for Tempo transactions.
Hosted Tempo fee-payer JSON-RPC fill support.
Tempo subscription key-authorization wire codec and verifier.
Canonical first-party machine-token (MPP Credits / machineUSD) charge routes.
EIP-712 proof credentials for zero-amount Tempo charge flows.
Session-intent receipt for Tempo — returned in the Payment-Receipt header
for session/pay-as-you-go payments.
Atomic aggregate in-flight accounting for Tempo fee sponsorship.
Tempo recurring-subscription activation and renewal.
Plug middleware implementing the MPP 402 payment handshake.
Validated configuration for MPP.Plug.
Per-method configuration within a multi-method endpoint.
Payment receipt — proof-of-payment returned in the Payment-Receipt header.
Server-side session credential action handlers.
State and TIP-1034 precompile identity for an MPP payment channel.
ETS-backed default implementation of MPP.Session.Store.
Convenience use wrapper that implements MPP.Method.verify/2 by dispatching
session credential actions through MPP.Session.Actions.
Session credential payload schema, discriminated on action.
Behaviour and dispatch helpers for pluggable session-channel persistence.
TIP-1034 Tempo Channel Reserve voucher and EIP-712 signature verification.
Single-node atomic ETS store for recurring subscriptions.
Persisted recurring-payment authority and settlement state.
Behaviour and dispatch helpers for recurring-subscription persistence.
Server-side payment observability via standard :telemetry events.
Built-in ETS-based atomic store using ConCache (TTL-enabled ETS wrapper by Saša Jurić).
Behaviour for atomic Tempo state stores used by MPP.Methods.Tempo.
Bare JSON-RPC 2.0 payment transport (non-MCP).
Plug adapter for the bare JSON-RPC payment transport.
Server-side WebSocket adapter for JSON-RPC plus MPP payment challenges.
Transport-neutral payment credential verification.
Mix Tasks
Starts a local HTTP server demonstrating the full MPP 402 payment flow.
Generates a static api_manifest.json from the library's descripex annotations.
Generates an OpenAPI 3.1.0 discovery document from an Elixir config file.