x402 on Algorand - Python

Build x402 HTTP-native payment applications on Algorand with Python. Use the reference files below for detailed guidance on each component.

Python Quick Start

# Minimal AVM support
pip install x402-avm[avm]

# Server frameworks (pick one)
pip install x402-avm[avm,fastapi]
pip install x402-avm[avm,flask]

# HTTP clients (pick one)
pip install x402-avm[avm,httpx]
pip install x402-avm[avm,requests]

# Everything
pip install x402-avm[all]

Register AVM Scheme

Every component registers the AVM exact scheme unconditionally — no environment variable guards:

# Client
from x402_avm.mechanisms.avm.exact.client import register_exact_avm_scheme
register_exact_avm_scheme(client, signer=my_signer)

# Server
from x402_avm.mechanisms.avm.exact.server import register_exact_avm_scheme
register_exact_avm_scheme(server)

# Facilitator
from x402_avm.mechanisms.avm.exact.facilitator import register_exact_avm_facilitator
register_exact_avm_facilitator(facilitator, signer=my_signer, networks=ALGORAND_TESTNET_CAIP2)

Python algosdk Encoding

Python algosdk's msgpack_decode() expects base64 strings, msgpack_encode() returns base64 strings. Boundary conversion: msgpack_decode(base64.b64encode(raw_bytes).decode()) / base64.b64decode(msgpack_encode(obj)).

Reference Guide

Navigate to the appropriate reference based on your task. Each topic has three files:

• {name}.md — Step-by-step implementation guide
• {name}-reference.md — API details and type signatures
• {name}-examples.md — Complete, runnable code samples

Explaining x402 for Python

Understand x402-avm Python package structure, extras installation ([avm], [fastapi], [flask], [httpx], [requests], [all]), signer protocols, async vs sync variants, and algosdk encoding boundaries.

• explain-algorand-x402-python.md — Package ecosystem explanation
• explain-algorand-x402-python-reference.md — API reference for x402-avm packages
• explain-algorand-x402-python-examples.md — Python pattern examples

Building Clients

Build HTTP clients with httpx (async) or requests (sync) that automatically handle 402 payments. Covers wrapHttpxWithPayment, wrapRequestsWithPayment, ClientAvmSigner for payment signing.

• create-python-x402-client.md — Client creation guide
• create-python-x402-client-reference.md — httpx/requests API reference
• create-python-x402-client-examples.md — Client code examples

Building Servers

Build payment-protected servers with FastAPI (async) or Flask (sync) middleware. Covers route pricing, PaymentMiddlewareASGI, Flask PaymentMiddleware, and multi-network support.

• create-python-x402-server.md — Server creation guide
• create-python-x402-server-reference.md — FastAPI/Flask middleware API reference
• create-python-x402-server-examples.md — Server code examples

Building Facilitators and Bazaar Discovery

Build facilitator services that verify and settle Algorand payments on-chain. Covers FacilitatorAvmSigner protocol, register_exact_avm_facilitator, FastAPI facilitator endpoints (/verify, /settle, /supported), and Bazaar discovery extension for automatic cataloging and indexing of payment-gated APIs (declare_discovery_extension, extract_discovery_info, bazaar_resource_server_extension).

• create-python-x402-facilitator.md — Facilitator creation guide (includes Bazaar setup in Steps 6-10)
• create-python-x402-facilitator-reference.md — Facilitator + Bazaar API reference
• create-python-x402-facilitator-examples.md — Facilitator + Bazaar code examples

Low-Level SDK Usage

Use x402-avm core components and AVM mechanism directly for custom integrations. Covers x402Client, x402ResourceServer, x402Facilitator, AVM signer protocols, constants, utilities, transaction encoding, and fee abstraction.

• use-python-x402-core-avm.md — Core SDK usage guide
• use-python-x402-core-avm-reference.md — Core/AVM API reference
• use-python-x402-core-avm-examples.md — Core SDK code examples

Python Package Quick Reference

| Install Extra | Purpose | | ------------- | ------- | | x402-avm[httpx] | Async HTTP client with automatic 402 payment handling | | x402-avm[requests] | Sync HTTP client with automatic 402 payment handling | | x402-avm[fastapi] | FastAPI async payment middleware | | x402-avm[flask] | Flask sync payment middleware | | x402-avm[avm] | Core AVM mechanism (signers, transaction builders, constants) | | x402-avm[all] | All extras combined |

How to Use This Skill

1. Start here to understand which reference you need
2. Read the {name}.md file for step-by-step implementation guidance
3. Consult {name}-reference.md for API details
4. Use {name}-examples.md for complete, runnable code samples