Reference

Rails

Pellet is rail-neutral. Wherever agent payments settle to a public ledger, the same methodology applies: ingest events, match to watched entities, attribute routing, surface provenance. Below is the current map of payment rails relevant to autonomous agents — what we index live, what we document, what we're watching.

Tempo MPP

Tempo

INDEXED · LIVE

Stable-native payment rail with native HTTP 402 challenge/response. Each request advertises a recipient, currency, escrow contract; agents settle on-chain and the response unlocks. The Tempo MPP Gateway aggregates ~17 underlying providers (Anthropic, OpenAI, Gemini, Modal, fal.ai, etc.) behind a single settlement address.

Protocol: x402 + MPP request envelope
Settlement: USDC.e / USDT0 on Tempo (chainId 4217)
Observability: public on-chain ledger; per-event provenance
Pellet coverage: Live. Transfer events ingested hourly; gateway routing recovered via Settlement event (Pattern A) + calldata fingerprint (Pattern B). ~100% coverage of gateway txs by group.
Shipped: 2025

tempo.xyz/mpp ↗

Stripe Link Wallet for Agents

Stripe

DOCUMENTED

Launched the same day as this page. Agents call Link with payment credentials approved per-purchase by the user. Skill installable via `link.com/skill.md` — the convention Anthropic seeded that's now an emerging install standard for agent capabilities.

Protocol: Stripe Link + skill.md install convention
Settlement: Card / bank rails wrapped for agents; private
Observability: Stripe-only — no public ledger
Pellet coverage: None. Settlement happens off-chain inside Stripe's network; not externally indexable. Pellet documents the rail's existence and links to canonical sources, but cannot surface live volumes.
Shipped: 2026-04-29

link.com/agents ↗

x402 (direct, off-Tempo)

Coinbase + community

WATCHING

The protocol underneath both Tempo MPP and Coinbase's agent payment kit. Open spec. Chain-agnostic. As more agents bypass aggregators and call x402 endpoints directly on Base/Optimism/etc., those flows become Pellet-indexable too.

Protocol: HTTP 402 + EIP-3009 transferWithAuthorization
Settlement: USDC on Base, Optimism, Polygon, etc.
Observability: public on-chain (chain-by-chain)
Pellet coverage: Watching. Each chain that sees meaningful x402 activity is a candidate for a rail expansion — same Pellet methodology applies (decode Transfers, attribute via tx context).
Shipped: 2024

x402.org ↗

MCP-native payments

Anthropic ecosystem

WATCHING

Not a payment rail itself — a discovery + invocation protocol that payment-aware servers ride. As agents adopt MCP for tool use, pay-per-call MCP servers will follow. Pellet would index whichever ones settle to public ledgers.

Protocol: Model Context Protocol — payment-capable servers
Settlement: Provider-defined (varies)
Observability: Provider-dependent
Pellet coverage: Watching. MCP servers that ship payment flows can settle on whatever rail they choose — some will be on-chain, some won't. Where there's a public ledger, the Pellet methodology applies.
Shipped: ongoing

modelcontextprotocol.io ↗

Missing a rail? Open an issue at pelletnetwork/pellet. The bar for inclusion: it carries autonomous-agent payments and is either indexed, documented, or worth catalogueing.