Which agent payment rails and x402 facilitators exist for onchain agents?

Open HTTP 402 payment protocol, now at the x402 Foundation: agents pay per request in stablecoins, and by a newly merged spec, in bitcoin over Lightning.

Official MCP server for BlindPay's stablecoin payment rails: payouts, payins, virtual accounts, and FX quotes.

Open protocol from Google for secure agent-led payments across traditional and crypto rails, with a crypto-native x402 extension built with Coinbase, Ethereum Foundation, and MetaMask.

Stripe's merchant-side agent payments: charge agents per call over MPP (cards via SPTs, USDC on Tempo and Solana) or x402 (USDC on Base), settled to your Stripe balance.

Lightning Labs reverse proxy that puts any HTTP or gRPC API behind L402: Lightning invoices plus macaroon credentials, answered with HTTP 402.

Managed AWS service that lets agents pay for APIs, MCP servers and content over x402 and MPP, using Coinbase CDP or Stripe Privy wallets with per-session budgets.

Neuronto Payments is an API and SDK.

Specification for the Payment HTTP auth scheme (Machine Payments Protocol) from Tempo, the Stripe/Paradigm-backed payments L1.

Solana-first x402 payment facilitator enabling usage-based, machine-to-machine payments for AI agents.

An x402 micropayment gateway and transparent proxy that adds pay-per-request paywalls to existing APIs without backend rewrites.

Cardano-based payment and identity protocol letting AI agents pay each other via escrow with on-chain audit trails.

One-line x402 paywall SDK for monetizing APIs and MCP servers with per-route USDC pricing.

PayRam's MCP server for self-hosted crypto payments: hosted endpoints and agent payment workflows.

L402 payments platform and MCP server letting agents pay for API access with Bitcoin Lightning or stablecoins.

Multi-tenant x402 facilitator for Lightning built on Nostr Wallet Connect. Predates the merged lnbtc spec and still advertises bip122.

Stablecoin payments infrastructure (acquired by Stripe) offering an orchestration, issuance, cards, and wallet API for moving money onchain.

Alchemy's payment proxy for AI agents — every API request is authenticated, metered, and settled automatically, so agents pay per call without keys or subscriptions.

Stablecoin-to-real-world spending for agents: prepaid and gift cards, Venmo/PayPal/ACH payouts. Callable via x402 (USDC on Base/Solana) or MCP.

Policy and audit layer for agent-initiated business payments, with an SDK, a CLI and MCP support over bank, card and stablecoin rails.

One prepaid balance that lets AI agents buy data, APIs, and tools per call - no API keys, no subscriptions.

Spend-control layer for agent payments: per-agent wallets, spend limits, human approval, scoped virtual cards and an audit trail, in front of the rails you already use.

TypeScript SDK to put a payment plan in front of an agent: credit or time-based plans, x402 access tokens, and A2A and MCP integrations.

Identity and payment layer for agents: KYAPay tokens carry an agent's identity and a USDC-backed payment commitment, with a hosted MCP server.