MoltsPay Python SDK

March 23, 2026 · View on GitHub

Python SDK for MoltsPay - Agent-to-Agent Payments.

MoltsPay enables AI agents to pay each other for services using the x402 protocol - HTTP-native payments with USDC stablecoins. No gas fees for clients, no complex wallet management.

What is MoltsPay?

MoltsPay is blockchain payment infrastructure designed for AI agents. It solves a fundamental problem: how do autonomous AI agents pay for services?

🤖 Agent-to-Agent Commerce - AI agents can autonomously discover, pay for, and use services
💨 Gasless Payments - Clients never pay gas on any chain
🔗 x402 Protocol - HTTP 402 Payment Required - payments as native HTTP flow
🔒 Spending Limits - Set per-transaction and daily limits for safety
⛓️ Multi-Chain - Base, Polygon, Solana, BNB, Tempo (mainnet & testnet)
🌐 Multi-VM - EVM chains + Solana (SVM) with unified API
🦜 LangChain Ready - Drop-in tools for LangChain agents

Installation

pip install moltspay

For Solana support:

pip install moltspay[solana]

For LangChain integration:

pip install moltspay[langchain]

For everything:

pip install moltspay[all]

Quick Start

from moltspay import MoltsPay

# Initialize (auto-creates wallet if not exists)
client = MoltsPay()
print(f"Wallet address: {client.address}")

# Discover services from a provider
services = client.discover("https://juai8.com/zen7")
for svc in services:
    print(f"{svc.id}: {svc.price} {svc.currency}")

# Pay for a service
result = client.pay(
    "https://juai8.com/zen7",
    "text-to-video",
    prompt="a cat dancing on the beach"
)
print(result.result)

Supported Chains

MoltsPay supports 8 chains across EVM and Solana (SVM):

Chain	Network ID	Type	Protocol	Gas Model
Base	eip155:8453	Mainnet	x402 + CDP	Gasless (CDP pays)
Polygon	eip155:137	Mainnet	x402 + CDP	Gasless (CDP pays)
Solana	solana:mainnet	Mainnet	x402 + SOL Facilitator	Gasless (server pays)
BNB	eip155:56	Mainnet	x402 + BNB Facilitator	Gasless (server pays)
Base Sepolia	eip155:84532	Testnet	x402 + CDP	Gasless (CDP pays)
Solana Devnet	solana:devnet	Testnet	x402 + SOL Facilitator	Gasless (server pays)
BNB Testnet	eip155:97	Testnet	x402 + BNB Facilitator	Gasless (server pays)
Tempo Moderato	eip155:42431	Testnet	MPP	Gas-free native

Key: Clients never pay gas on any chain. Different facilitators handle settlement.

Payment Protocols

MoltsPay uses different protocols optimized for each chain:

x402 + CDP (Base, Polygon)

Standard x402 flow with Coinbase Developer Platform as facilitator:

Client                         Server                      CDP Facilitator
  │ POST /execute                │                              │
  │ ─────────────────────────>   │                              │
  │ 402 + payment requirements   │                              │
  │ <─────────────────────────   │                              │
  │ [Sign EIP-3009 - NO GAS]     │                              │
  │ POST + X-Payment header      │                              │
  │ ─────────────────────────>   │ Verify & settle              │
  │                              │ ─────────────────────────>   │
  │ 200 OK + result              │                              │
  │ <─────────────────────────   │                              │

x402 + SOL Facilitator (Solana)

Solana uses SPL token transfers with server as fee payer:

Client                         Server (Fee Payer)          Solana Network
  │ POST /execute                │                              │
  │ ─────────────────────────>   │                              │
  │ 402 + solanaFeePayer         │                              │
  │ <─────────────────────────   │                              │
  │ [Sign SPL Transfer - NO GAS] │                              │
  │ POST + X-Payment header      │                              │
  │ ─────────────────────────>   │ Execute + pay ~\$0.001 SOL    │
  │                              │ ─────────────────────────>   │
  │ 200 OK + result              │                              │
  │ <─────────────────────────   │                              │

Key: Client only signs. Server acts as fee payer and executes transaction.

x402 + BNB Facilitator (BNB Chain)

BNB uses EIP-712 intent signing with server-sponsored gas:

Client                         Server                      BNB Network
  │ POST /execute                │                              │
  │ ─────────────────────────>   │                              │
  │ 402 + bnbSpender             │                              │
  │ <─────────────────────────   │                              │
  │ [Sign EIP-712 Intent-NO GAS] │                              │
  │ POST + X-Payment header      │                              │
  │ ─────────────────────────>   │ Execute + pay ~\$0.0001 gas   │
  │                              │ ─────────────────────────>   │
  │ 200 OK + result              │                              │
  │ <─────────────────────────   │                              │

Key: Client only signs intent. Server executes transferFrom and pays gas.

MPP (Tempo Moderato)

Machine Payments Protocol - client executes directly (gas-free on Tempo):

Client                         Server
  │ POST /execute                │
  │ ─────────────────────────>   │
  │ 402 + WWW-Authenticate       │
  │ <─────────────────────────   │
  │ [Execute TIP-20 - NO GAS]    │
  │ POST + Authorization header  │
  │ ─────────────────────────>   │
  │ 200 OK + result              │
  │ <─────────────────────────   │

Key: Tempo is natively gas-free. Client executes transfer directly.

Testnet Quick Start

Test without real money using our faucets:

from moltspay import MoltsPay

# === Base Sepolia (x402 + CDP) ===
client = MoltsPay(chain="base_sepolia")
result = client.faucet()  # 1 USDC, once per 24h
print(f"Got {result.amount} USDC!")

# === Solana Devnet (x402 + SOL) ===
client = MoltsPay(chain="solana_devnet")
result = client.faucet()  # 1 USDC
print(f"Got {result.amount} USDC!")

# === BNB Testnet (x402 + BNB) ===
client = MoltsPay(chain="bnb_testnet")
result = client.faucet()  # 1 USDC + 0.001 tBNB for gas
print(f"Got {result.amount} USDC!")

# === Tempo Moderato (MPP) ===
client = MoltsPay(chain="tempo_moderato")
result = client.faucet()  # 1 pathUSD
print(f"Got {result.amount} pathUSD!")

Make test payments:

# Base Sepolia
result = MoltsPay(chain="base_sepolia").pay(
    "https://juai8.com/zen7", "text-to-video",
    prompt="a robot dancing"
)

# Solana Devnet
result = MoltsPay(chain="solana_devnet").pay(
    "https://juai8.com/zen7", "text-to-video",
    prompt="a cat playing piano"
)

# BNB Testnet
result = MoltsPay(chain="bnb_testnet").pay(
    "https://juai8.com/zen7", "text-to-video",
    prompt="a sunset timelapse"
)

# Tempo Moderato
result = MoltsPay(chain="tempo_moderato").pay(
    "https://juai8.com/zen7", "text-to-video",
    prompt="an ocean wave"
)

Features

Auto Wallet Management

Wallets are automatically created on first run:

EVM wallet: ~/.moltspay/wallet.json (Base, Polygon, BNB, Tempo)
Solana wallet: ~/.moltspay/wallet-solana.json

from moltspay import MoltsPay

client = MoltsPay()
print(f"EVM Address: {client.address}")

# Solana address (if initialized)
client_sol = MoltsPay(chain="solana")
print(f"Solana Address: {client_sol.address}")

Funding Your Wallet

Before making payments, you need USDC in your wallet.

Option 1: Testnet Faucets (Free)

from moltspay import MoltsPay

# Base Sepolia - 1 USDC (once per 24h)
client = MoltsPay(chain="base_sepolia")
result = client.faucet()

# Solana Devnet - 1 USDC
client = MoltsPay(chain="solana_devnet")
result = client.faucet()

# BNB Testnet - 1 USDC + 0.001 tBNB for gas
client = MoltsPay(chain="bnb_testnet")
result = client.faucet()

# Tempo Moderato - 1 pathUSD
client = MoltsPay(chain="tempo_moderato")
result = client.faucet()

Option 2: Coinbase Onramp (Mainnet)

Buy USDC with debit card or Apple Pay:

from moltspay import MoltsPay

client = MoltsPay()  # Default: Base mainnet

# Generate funding link
result = client.fund(10)  # \$10 minimum
print(f"Open this URL to pay: {result.url}")

# Or print QR code to terminal
client.fund_qr(10)

Option 3: Direct Transfer (Mainnet)

Send USDC from any wallet:

from moltspay import MoltsPay

client = MoltsPay()
print(f"Send USDC to: {client.address}")
print(f"Chain: Base (chainId: 8453)")

⚠️ Important: Send USDC on the correct chain!

Multi-Chain Payments

from moltspay import MoltsPay

# Pay on different chains
result = MoltsPay(chain="base").pay(...)           # Base mainnet
result = MoltsPay(chain="polygon").pay(...)        # Polygon mainnet
result = MoltsPay(chain="solana").pay(...)         # Solana mainnet
result = MoltsPay(chain="bnb").pay(...)            # BNB mainnet
result = MoltsPay(chain="base_sepolia").pay(...)   # Base testnet
result = MoltsPay(chain="solana_devnet").pay(...)  # Solana testnet
result = MoltsPay(chain="bnb_testnet").pay(...)    # BNB testnet
result = MoltsPay(chain="tempo_moderato").pay(...) # Tempo testnet

Spending Limits

Control your agent's spending:

from moltspay import MoltsPay

client = MoltsPay()

# Check current limits
limits = client.limits()
print(f"Max per tx: {limits.max_per_tx}")
print(f"Max per day: {limits.max_per_day}")
print(f"Spent today: {limits.spent_today}")

# Update limits
client.set_limits(max_per_tx=20, max_per_day=200)

Check Balances

from moltspay import MoltsPay

client = MoltsPay()

# Single chain balance
balance = client.balance()
print(f"USDC: {balance.usdc}")
print(f"Chain: {balance.chain}")

# All chain balances
balances = client.all_balances()
for chain, bal in balances.items():
    print(f"{chain}: {bal.get('usdc', 0)} USDC")

BNB Approval Check

BNB requires a one-time approval before first payment:

from moltspay import MoltsPay

client = MoltsPay(chain="bnb")

# Check approval status
approvals = client.check_bnb_approvals()
print(f"USDC approved: {approvals['usdc_approved']}")
print(f"Allowance: {approvals['usdc_allowance']}")

Note: First BNB payment auto-approves. Approval costs ~$0.0001 in BNB gas (paid by client once).

Async Support

import asyncio
from moltspay import AsyncMoltsPay

async def main():
    async with AsyncMoltsPay() as client:
        result = await client.pay(
            "https://juai8.com/zen7",
            "text-to-video",
            prompt="a cat dancing"
        )
        print(result.result)

asyncio.run(main())

Error Handling

from moltspay import MoltsPay, InsufficientFunds, LimitExceeded, PaymentError

client = MoltsPay()

try:
    result = client.pay(...)
except InsufficientFunds as e:
    print(f"Need {e.required} USDC, have {e.balance}")
except LimitExceeded as e:
    print(f"Exceeds {e.limit_type} limit: {e.amount} > {e.limit}")
except PaymentError as e:
    print(f"Payment failed: {e}")

API Reference

Methods

Method	Description	Returns
`pay(url, service_id, **params)`	Pay for and execute a service	`PaymentResult`
`discover(url)`	List services from a provider	`List[Service]`
`balance(chain=None)`	Get wallet balance	`Balance`
`all_balances()`	Get balances on all chains	`Dict[str, Dict]`
`limits()`	Get current spending limits	`Limits`
`set_limits(max_per_tx, max_per_day)`	Set spending limits	`None`
`faucet()`	Get free testnet tokens	`FaucetResult`
`fund(amount)`	Open Coinbase funding page	`FundingResult`
`fund_qr(amount)`	Print funding QR code	`FundingResult`
`check_bnb_approvals(chain="bnb")`	Check BNB approval status	`Dict`

Properties

Property	Description	Type
`address`	Wallet address (EVM or Solana)	`str`

The `.pay()` Method

result = client.pay(
    provider_url: str,         # e.g., "https://juai8.com/zen7"
    service_id: str,           # e.g., "text-to-video"  
    token: str = "USDC",       # "USDC" or "USDT"
    **params                   # Service-specific parameters
)

PaymentResult Object

result.success      # bool - True if payment succeeded
result.amount       # float - Amount paid
result.token        # str - "USDC" or "USDT"
result.tx_hash      # str - Blockchain transaction hash
result.result       # Any - Service result (e.g., video URL)
result.error        # str | None - Error message if failed
result.explorer_url # str | None - Block explorer link

FaucetResult Object

result.success      # bool - True if faucet succeeded
result.amount       # float - Amount received
result.tx_hash      # str - Transaction hash
result.error        # str | None - Error message if failed

LangChain Integration

from langchain.agents import initialize_agent, AgentType
from langchain_openai import ChatOpenAI
from moltspay.integrations.langchain import MoltsPayTool

llm = ChatOpenAI(model="gpt-4")
tools = [MoltsPayTool()]

agent = initialize_agent(
    tools, 
    llm, 
    agent=AgentType.OPENAI_FUNCTIONS,
    verbose=True
)

# Agent can now pay for AI services!
result = agent.run("Generate a video of a cat dancing on the beach")

Available Tools

from moltspay.integrations.langchain import get_moltspay_tools

tools = get_moltspay_tools()  # Returns both tools

Tool	Description
`MoltsPayTool`	Pay for and execute services
`MoltsPayDiscoverTool`	Discover available services and prices

Chain-Specific Notes

Solana

Wallet: Separate ed25519 keypair at ~/.moltspay/wallet-solana.json
Gas: Server pays (~$0.001 SOL per tx)
Token: Circle USDC SPL token

USDC Mint Addresses:

Network	Address
Mainnet	`EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v`
Devnet	`4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU`

BNB Chain

Decimals: 18 (not 6 like Base/Polygon)
Gas: Server pays (~$0.0001 per tx)
Approval: First payment requires one-time approval (client pays ~$0.0001)

Token Addresses:

Token	Address
USDC	`0x8AC76a51cc950d9822D68b83fE1Ad97B32Cd580d`
USDT	`0x55d398326f99059fF775485246999027B3197955`

Tempo Moderato

Protocol: MPP (Machine Payments Protocol)
Gas: Native gas-free
Explorer: https://explore.testnet.tempo.xyz

Stablecoins:

Token	Address
pathUSD (USDC)	`0x20c0000000000000000000000000000000000000`
alphaUSD (USDT)	`0x20c0000000000000000000000000000000000001`

Live Example: Zen7 Video Generation

Live service at https://juai8.com/zen7

Services:

text-to-video - $0.01 USDC
image-to-video - $0.01 USDC

Supported Chains: Base, Polygon, Solana, BNB, Tempo (mainnet & testnet)

from moltspay import MoltsPay

# Pay on Base (default)
result = MoltsPay().pay(
    "https://juai8.com/zen7", "text-to-video",
    prompt="a happy cat"
)

# Pay on Solana
result = MoltsPay(chain="solana_devnet").pay(
    "https://juai8.com/zen7", "text-to-video",
    prompt="a happy cat"
)

print(result.result)  # {"video_url": "https://..."}

CLI Compatibility

Wallet format is fully compatible with the Node.js CLI:

# Create wallet with Node CLI
npx moltspay init

# Use same wallet in Python
python -c "from moltspay import MoltsPay; print(MoltsPay().address)"

moltspay (Node.js) - Node.js SDK and CLI
x402 Protocol - The HTTP payment standard

Community & Support

Discord: https://discord.gg/QwCJgVBxVK
Website: https://moltspay.com
PyPI: https://pypi.org/project/moltspay/
npm (Node.js): https://www.npmjs.com/package/moltspay
GitHub: https://github.com/Yaqing2023/moltspay-python

License

MIT