Wrap the standard openai.OpenAI client with a crypto wallet. When the server responds with HTTP 402, the library automatically signs and retries the request — zero code changes needed.

Installation

pip install x402-openai[evm]          # Ethereum / Base / …
pip install x402-openai[svm]          # Solana
pip install x402-openai[all]          # all chains

Quick Start

from x402_openai import X402OpenAI
from x402_openai.wallets import EvmWallet

client = X402OpenAI(wallet=EvmWallet(private_key="0x…"))

res = client.chat.completions.create(
    model="openai/gpt-4o-mini",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(res.choices[0].message.content)

Swap EvmWallet for SvmWallet to pay on Solana — the API is identical.

Usage

Async & Streaming

from x402_openai import AsyncX402OpenAI

client = AsyncX402OpenAI(wallet=EvmWallet(private_key="0x…"))

stream = await client.chat.completions.create(
    model="openai/gpt-4o-mini",
    messages=[{"role": "user", "content": "Explain x402"}],
    stream=True,
)
async for chunk in stream:
    if chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="")

Multi-chain

from x402_openai.wallets import EvmWallet, SvmWallet

client = X402OpenAI(wallets=[
    EvmWallet(private_key="0x…"),
    SvmWallet(private_key="base58…"),
])

BIP-39 Mnemonic (EVM)

wallet = EvmWallet(mnemonic="word1 word2 … word12")
wallet = EvmWallet(mnemonic="…", account_index=2)                  # m/44'/60'/0'/0/2
wallet = EvmWallet(mnemonic="…", derivation_path="m/44'/60'/2'/0/0")  # custom path

The protocol selects the right chain automatically based on the server's payment requirements.

Payment Policies

Use policies to control which chain or scheme is preferred when multiple payment options are available:

from x402_openai import X402OpenAI, prefer_network, prefer_scheme, max_amount
from x402_openai.wallets import EvmWallet, SvmWallet

client = X402OpenAI(
    wallets=[
        EvmWallet(private_key="0x…"),
        SvmWallet(private_key="base58…"),
    ],
    policies=[
        prefer_network("eip155:8453"),  # Prefer Base mainnet
        prefer_scheme("exact"),         # Prefer exact payment scheme
        max_amount(1_000_000),          # Cap at 1 USDC (6 decimals)
    ],
)

API Reference

X402OpenAI / AsyncX402OpenAI

Drop-in replacement for openai.OpenAI / openai.AsyncOpenAI. Provide exactly one credential source:

All standard OpenAI kwargs (base_url, timeout, max_retries, …) are forwarded. Default base_url: https://llm.qntx.fun/v1

Wallet Adapters

Implement the Wallet protocol to add a new chain.

Low-level Transports

X402Transport / AsyncX402Transport — httpx transports for manual wiring into any httpx.Client.

Examples

See the examples/ directory. Each script is self-contained:

EVM_PRIVATE_KEY="0x…"           python examples/chat_evm.py
SOLANA_PRIVATE_KEY="base58…"    python examples/chat_svm.py
EVM_PRIVATE_KEY="0x…"           python examples/streaming_evm.py
MNEMONIC="word1 word2 …"       python examples/chat_evm_mnemonic.py
EVM_PRIVATE_KEY="0x…"           python examples/chat_evm_policy.py
EVM_PRIVATE_KEY="0x…"           python examples/streaming_evm_policy.py

License

This project is licensed under the MIT License.