Live on Solana Devnet

Agents need to
pay each other.
We built the pipes.

Full x402 payment infrastructure — escrow settlement with PDA vaults, marketplace fees, 36 paid MCP tools, and ERC-8004 reputation. Solana + Base. Not a demo. Deployed.

See Live Endpoints View Source
curl — x402 payment flow 
$ curl -i https://x402-api.purplesquirrelnetworks.workers.dev/api/chat

HTTP/1.1 402 Payment Required
x-payment-address: EPjFWdd5...USDC
x-payment-amount:  0.01
x-payment-chain:   solana
x-payment-token:   USDC

# Agent signs USDC transfer, retries with proof

$ curl -X POST /api/chat \
  -H "x-payment: <signed_tx>" \
  -d '{"prompt":"explain x402"}'

HTTP/1.1 200 OK
# → USDC deposited to escrow PDA
# → Service delivered
# → Provider paid, 3% to treasury
5 Instructions
36 Paid MCP Tools
2 Chains
3% Marketplace Fee
The Problem

Raw x402 is just a transfer.
Agents need settlement infrastructure.

The x402 standard gives HTTP a payment layer — return 402, client signs a transaction, retry with proof. Coinbase shipped the spec. Google adopted it. Nous Research bills Hermes inference through it.

But raw x402 just moves tokens from A to B. No escrow. No timeout protection. No marketplace economics. No reputation. No way for an agent to know if the provider is legit.

We built the missing layer. An Anchor escrow program locks USDC in PDA vaults with configurable timeouts. A Rust facilitator verifies payment signatures and settles through the program. Marketplace fees sustain the network. ERC-8004 identity gives agents verifiable reputation backed by payment proofs.

36 MCP tools are already payment-gated — NVIDIA AI inference, Pixelmator ML processing, NemoClaw agent sandboxing. Not theoretical. Running on devnet with real program state.

Payment Flow

Five steps. Fully on-chain.

01

402 Response

Client hits API endpoint. Server returns HTTP 402 with USDC payment requirements — amount, address, chain, token.

02

Client Signs

Agent wallet signs an SPL Token TransferChecked instruction. Supports both Solana (native) and Base (EIP-3009 gasless).

03

Facilitator Verifies

Rust facilitator deserializes the transaction, validates the USDC transfer matches requirements. No trust needed — math checks out or it doesn't.

04

Escrow Deposits

USDC locked in a PDA vault via the Anchor program. Configurable timeout. Client protected — refund after expiry if service doesn't deliver.

05

Settlement

Service delivers → facilitator calls release → provider gets paid, 3% goes to PSM treasury. Vault closes, rent returned to client.

Architecture

Three repos. One settlement layer.

◇ TypeScript

x402

Core project. Express server with x402 middleware, MCP server with 3 paid tools, Cloudflare Worker proxying NVIDIA endpoints, and a fetch client with auto-signing.

Express 5 Hono viem @solana/kit MCP SDK
View Repo →
◆ Rust / Anchor

x402-escrow

Anchor program deployed on Solana devnet. USDC escrow with PDA vaults, configurable marketplace fees (up to 10%), timeout-based refunds, global settlement stats.

Anchor 0.30 SPL Token PDA Vaults Events
HdtjdK2g4NhRuAuyTjhX9msUeEuzGHDfEKxVM7vvFzU9
View Repo →
◇ Rust

x402-facilitator

Axum HTTP server. Verifies SPL Token payment signatures, settles through the Anchor escrow program via CPI. Supports devnet and mainnet.

Axum 0.8 solana-sdk spl-token tokio
View Repo →
Agent Framework

elizaOS plugin. Drop-in payments.

@psm/elizaos-x402 is the first Solana-native x402 plugin for elizaOS. Works with Milady, any elizaOS agent, or custom runtimes. Seven actions, two context providers.

PAY_FOR_SERVICEFull 402 payment flow
CREATE_ESCROWLock USDC in PDA vault
RELEASE_ESCROWPay provider + fee
REFUND_ESCROWReturn on timeout
REGISTER_AGENT8004 + MIP-14 identity
CHECK_REPUTATIONQuery trust score
SUBMIT_FEEDBACKProofPass review
View Plugin →
character.json 
{
  "name": "x402 Agent",
  "plugins": [
    "@elizaos/plugin-sql",
    "@elizaos/plugin-anthropic",
    "@psm/elizaos-x402"
  ],
  "secrets": {
    "X402_SOLANA_CLUSTER": "devnet",
    "X402_ESCROW_PROGRAM": "HdtjdK2g..."
  }
}
Live API

Payment-gated endpoints. Running now.

All endpoints return 402 with USDC payment requirements. Sign and retry with proof.

Endpoint Price Backend Chain
POST /api/chat $0.01 NVIDIA Nemotron 49B Solana
POST /api/code $0.02 Qwen Coder 480B Solana
POST /api/embed $0.005 Nemotron Embed 1B Solana
POST /api/safety $0.005 6 NVIDIA Safety Models Solana
POST /api/rerank $0.005 Nemotron Rerank 1B Solana
https://x402-api.purplesquirrelnetworks.workers.dev
MCP Ecosystem

36 tools. Pay-per-call.

nvidia-mcp

13 paid tools

AI inference, code review, RAG, translation, safety scanning, financial analysis, podcast generation. All NVIDIA NIM models.

$0.005 – $0.05 / call

pixelmator-mcp

10 paid + 13 free

ML-powered image processing. Super resolution, background removal, color grading, LUT application, auto-enhance, object detection.

$0.005 – $0.05 / call

nemoclaw-mcp

3 paid + 7 free

Sandboxed agent execution. Run untrusted code in isolated containers. Inference management, policy enforcement.

$0.005 – $0.02 / call
Trust Layer

ERC-8004.
Reputation backed by
payment proofs.

x402 handles payments. ERC-8004 handles trust. Each agent registers as an NFT in the Identity Registry on Base. Reputation scores are submitted with proofOfPayment containing the x402 transaction hash — only verified payers can leave reviews. Sybil-resistant by design.

Identity 0x8004A169...9432
Reputation 0x8004BAa1...9B63
PSM x402 Facilitator
— awaiting first reviews
x402Support: true escrow-management usdc-settlement
Registered on Base Sepolia
Dual Protocol

x402 for crypto. MPP for enterprise.

x402 Coinbase

  • HTTP 402 payment shim
  • Per-request settlement
  • USDC on Solana + Base
  • Permissionless, crypto-native
  • Indie APIs, decentralized services
Deployed

MPP Stripe / Tempo

  • Session-based streaming micropayments
  • 10,000+ TPS on Tempo chain
  • Hybrid fiat + crypto (Stripe Payment Tokens)
  • Full compliance stack included
  • Enterprise agent traffic
Integration Planned

Different markets, same stack. x402 captures the long tail. MPP captures enterprise throughput. Both settle to your treasury.

On-Chain State

Solana Devnet. Verified.

Escrow Program HdtjdK2g4NhRuAuyTjhX9msUeEuzGHDfEKxVM7vvFzU9
Config PDA 83knRYPC4pvc1H8jzcHbj5rGoz6eJgykz87hGGuxsG3V
Fee 300 bps (3%) to PSM treasury
Authority 39NsBBAySg8kjeWEBpdiYt1oWtbPCv3A6YFd86ZGyeyv
View on Solana Explorer →