Robinhood Payments Protocol

Programmable commerce for autonomous AI.

The open protocol that lets AI agents discover services, negotiate pricing, and exchange programmable value on Robinhood Chain.

Get started Read the RFCs

6 Primitives
7 RFCs
MIT Licensed
0 API Keys
Onchain Settlement

The lifecycle

Agent

Discovery

Quote

Commerce Session

Intent

Robinhood Chain

Receipt

RPP402 turns fragmented agent commerce into verifiable onchain settlement - automatically.

6: Primitives
Discovery to Receipt. Nothing else to learn.
1: Well-known file
One /.well-known/rpp.json and you're discoverable.
0: API keys
Public discovery, cryptographic settlement.

Open standard. RFC-first. MIT licensed.

Read RPP402-000 -Introduction→

Primitives

Six primitives. Nothing else.⁰¹

RPP402 v1 is deliberately small -Discovery, Quote, Commerce Session, Payment Intent, Settlement, and Receipt. Everything else is a future RFC.

RPP402-00101 / 06

Discovery

A Service publishes one JSON document at a well-known location -no registration, no API key, no approval process.

Read RFC→

RPP402-00202 / 06

Quote

A binding, time-limited price for one Capability call, requested independently of any purchase -so agents can shop before they commit.

Read RFC→

RPP402-00303 / 06

Commerce Session

The atomic container holding one or more Quotes, from one or more Services -RPP402's structural answer to multi-provider purchases.

Read RFC→

RPP402-00404 / 06

Payment Intent

Signed authorization to pay a Session's total, in a stablecoin or a tokenized real-world asset held in a Robinhood Agentic Account.

Read RFC→

RPP402-00505 / 06

Settlement

Execution on Robinhood Chain -a stablecoin transfer or a tokenized-security transfer, with idempotent, auditable transaction records.

Read RFC→

RPP402-00606 / 06

Receipt

Cryptographically verifiable proof a Session settled -checkable independently, without trusting the issuing Service's word for it.

Read RFC→

Commerce Session

One session, start to finish⁰²

The Commerce Session state machine -five transitions from an empty session to a verifiable receipt, defined in RPP402-003.

1
created
Agent opens a Session
A Commerce Session is created against one Service's endpoint -the session host for this purchase.
created
2
quoting
Legs are attached
The agent requests Quotes and attaches each as a leg. One call per provider -a Session can span several.
quoting
3
intent_authorized
Payment is authorized
A signed Payment Intent covers every leg's total in one asset -a stablecoin, or a tokenized security via an Agentic Account.
intent_authorized
4
settling → settled
Settlement executes
The intent settles onchain on Robinhood Chain automatically -no separate "pay now" call.
settling → settled
5
receipt_issued
Receipt is issued
A signed, onchain-verifiable Receipt is returned -checkable independently of the issuing Service.
receipt_issued

Architecture

Robinhood Chain is the settlement layer. RPP402 is the commerce layer.⁰³

RPP402 doesn't reimplement chain settlement -it standardizes what happens above it: how an agent finds a service, prices a purchase, and proves it happened.

AI Agents

Autonomous buyers and sellers of services, discovering and settling via RPP402.

RPP402

Commerce layer -Discovery, Quote, Session, Intent, Settlement, Receipt.

Robinhood Chain

Settlement layer -Arbitrum Orbit L2, tokenized RWA, Agentic Accounts.

SDK

One call per primitive⁰⁴

@rpp402/sdk mirrors the protocol exactly - discover() is RPP402-001, session.quote() through session.receipt() are RPP402-002 through RPP402-006. Every response is validated against the same JSON Schemas this code is generated against, at runtime, not just typed at compile time.

Three runtimes, one wire format

npm install @rpp402/sdkTypeScript pip install rpp402Python

use rpp402;Rust

One conformance suite across all three, so they agree on the wire format byte-for-byte.

TypeScript

import { createClient } from "@rpp402/sdk";

const rpp402 = createClient({ agentWallet: "0xaaaa...1234" });

const service = await rpp402.discover("market-data.example");
const session = await rpp402.session.create(service);

const quote = await session.quote(service, {
  capability: "market-data.quote",
  params: { ticker: "NVDA" },
  settlementAsset: service.supported_assets[0],
});

const intent = await session.intent({
  asset: quote.price.asset,
  authorization: {
    type: "agentic_account_delegation",
    account_id: "aa_...",
    delegation_ref: "del_...",
  },
});

const settlement = await session.settle();
const receipt = await session.receipt();

Specification

Read the spec, not the marketing⁰⁵

Every primitive is an RFC -Overview, Protocol, JSON Schema, Security, Errors, Reference Implementation. RPP402-000 also compares RPP402 directly to MPP and x402.

Browse all RFCs→

RFC	Title	Status
RPP402-000	Introduction	Active
RPP402-001	Discovery	Active
RPP402-002	Quote	Active
RPP402-003	Commerce Session	Active
RPP402-004	Payment Intent	Active
RPP402-005	Settlement	Active
RPP402-006	Receipt	Active

terminal

$ rpp402 init market-data-service
✓ Created market-data-service

$ cd market-data-service && rpp402 dev
market-data-service serving svc_marketdataservice on :4021

$ rpp402 simulate --capability example.echo --params '{"ticker":"NVDA"}'
quote_00000001   0.001 USDG   expires in 60s
  from market-data-service (svc_marketdataservice)

$ rpp402 receipts verify receipt.json
✓ schema valid
✓ signature is well-formed hex (signer: 0x18b9...967b)
✓ settlement_ref.tx_hash is well-formed
  Structural checks only -cryptographic signature recovery
  needs RPP402-006's EIP-712 payload formalized first.

$ rpp402 doctor
✓ Node.js version        v22.18.0 (need >=20.9)
✓ Inside an RPP402 project  market-data-service
✓ Agent wallet configured
✓ Service reachable      http://localhost:4021/.well-known/rpp.json
✓ Discovery document valid

Developer experiencelive

One CLI, from init to verified receipt⁰⁶

rpp402 scaffolds a real, zero-dependency service, simulates the protocol against it, and structurally verifies receipts -modeled on the Stripe CLI, Bun, and Wrangler. This transcript is real output from a real run, not a mockup.

Try it

Run the protocol, don't just read it⁰⁷

Three live surfaces -all real code against a real reference implementation, no canned data.

live

Playground

Inspect every primitive live -request, response, headers, timeline, latency. Chrome DevTools, Stripe Dashboard, and Postman, purpose-built for a Commerce Session.

Open Playground→live

Registry

Every RPP402 service publishes /.well-known/rpp.json -paste one into the Explorer to discover it live, search, filter, and inspect it.

Open Registry Explorer→live

Examples

Runnable @rpp402/sdk integrations -a basic purchase and a two-leg Commerce Session, read straight from the source their own test suite executes.

View Examples→

Who it's for

RPP402 for

Discover services, request quotes, and settle purchases with one SDK call per primitive -no API keys to manage.
Learn more→

Roadmap

What v1 leaves out, on purpose⁰⁸

Nineteen future RFCs, named and reasoned about, not designed ahead of real usage -grouped by theme, each with why it's deferred.

View full roadmap→

RPP402-010Subscriptions
RPP402-011Streaming
RPP402-012Escrow
RPP402-013Wallet Delegation
RPP402-014Marketplace
RPP402-015Machine Reputation
RPP402-016Identity
RPP402-017Notifications
RPP402-018Invoices
RPP402-019Spend Limits
RPP402-020Analytics
RPP402-021Webhooks
RPP402-022Policy Engine
RPP402-023Usage Metering
RPP402-024Enterprise
RPP402-025Cross-chain
RPP402-026Recurring Billing
RPP402-027Treasury
RPP402-028MPP / x402 Interoperability

Install

A published standard, shipped as packages

The MIT-licensed packages are live on npm under the @rpp402 scope. The spec is public to read now, and the code is one install away.

npm

npm install @rpp402/sdk @rpp402/cli

Read the RFCs View on npm

Token

RPP402 on Robinhood Chain

$RPP402 is the community token for the protocol, trading on Uniswap v3. The protocol settles in stablecoins and tokenized assets - the token is the ecosystem around it.

Price

Market cap

Liquidity

Contract · Robinhood Chain

0x94fef3763ed87051267dcd7ffc5df416b6c03a7e

Chart

View tokenomics Chart on DexScreener

Robinhood Payments Protocol

RPP402 turns fragmented agent commerce into verifiable onchain settlement - automatically.

Six primitives. Nothing else.01

Discovery

Quote

Commerce Session

Payment Intent

Settlement

Receipt

One session, start to finish02

Agent opens a Session

Legs are attached

Payment is authorized

Settlement executes

Receipt is issued

Robinhood Chain is the settlement layer. RPP402 is the commerce layer.03

One call per primitive04

Read the spec, not the marketing05

One CLI, from init to verified receipt06

Run the protocol, don't just read it07

Playground

Registry

Examples

RPP402 for

What v1 leaves out, on purpose08

A published standard, shipped as packages

RPP402 on Robinhood Chain

Six primitives. Nothing else.⁰¹

One session, start to finish⁰²

Robinhood Chain is the settlement layer. RPP402 is the commerce layer.⁰³

One call per primitive⁰⁴

Read the spec, not the marketing⁰⁵

One CLI, from init to verified receipt⁰⁶

Run the protocol, don't just read it⁰⁷

What v1 leaves out, on purpose⁰⁸