primer-x402

Primer ecosystem toolkit for x402. Built on the official x402 SDK.

This package extends the official x402 SDK with Primer-specific infrastructure: our facilitator, SKALE network support, Robinhood Chain support, and Prism ERC-20 settlement.

Installation

pip install primer-x402

This automatically installs x402 as a dependency.

Quick Start

Using Primer's Facilitator

from primer_x402 import primer_facilitator, primer_facilitator_sync

# Async client
facilitator = primer_facilitator()
result = await facilitator.verify(payload, requirements)

# Sync client
facilitator_sync = primer_facilitator_sync()
result = facilitator_sync.verify(payload, requirements)

SKALE Networks (Gas-Free)

from primer_x402 import skale_networks

# Use SKALE for gas-free transactions
network = skale_networks.base           # "eip155:1187947933"
network = skale_networks.base_sepolia   # "eip155:324705682"

Robinhood Chain

from primer_x402 import robinhood_networks

# Use Robinhood Chain
network = robinhood_networks.mainnet    # "eip155:4663"
network = robinhood_networks.testnet    # "eip155:46630"

Prism ERC-20 Settlement

For standard ERC-20 tokens (not USDC/EURC), use Prism:

from eth_account import Account
from web3 import Web3
from primer_x402 import create_prism_payload, PrismPaymentParams

web3 = Web3(Web3.HTTPProvider("https://mainnet.base.org"))
account = Account.from_key("0x...")

payload = create_prism_payload(
    account,
    web3,
    PrismPaymentParams(
        token="0x...",  # ERC-20 token address
        to="0x...",     # Recipient
        value=1000000,  # Amount in smallest unit
    ),
    "eip155:8453",
)

Note: Payers must first approve the Prism contract (0x402357ff1e18d42d0f14a5d56d6e1ebd741b3a86) to spend their tokens.

CLI

The package includes a CLI for scaffolding new x402 projects.

Create a Paid AI Proxy (Chutes)

Scaffold a FastAPI server that proxies Chutes (Bittensor Subnet 64) AI endpoints with x402 micropayments:

primer-x402 create chutes-proxy my-ai-api
cd my-ai-api
python -m venv venv
source venv/bin/activate  # or venv\Scripts\activate on Windows
pip install -r requirements.txt

Edit main.py to set your wallet address:

RECIPIENT = "0xYourWalletAddress"

Set your Chutes API key and run:

cp .env.example .env
# Edit .env with your CHUTES_API_KEY
export $(cat .env | xargs)
uvicorn main:app --reload

The generated proxy exposes these paid endpoints:

Payments are verified via Primer's facilitator and accepted on Base mainnet. Edit the generated code to customize pricing, networks, or add additional endpoints.

API Reference

Facilitator

Networks

Prism Settlement

Supported Networks

Links

• x402 Protocol
• Official x402 SDK
• Primer Systems
• TypeScript SDK

License

Apache-2.0 — Primer Systems