x402 Explained: HTTP‑Native Micropayments for AI Agents (With Real Code)

Описание и применение

x402 позволяет автономным агентам оплачивать запросы к сервисам через HTTP‑заголовок, устраняя необходимость в статических ключах и сложных схемах биллинга.

Задача

AI agents need to pay for service calls without carrying static credentials or managing billing cycles, which clashes with their stateless, transient nature.

Результат

Agents can perform stateless, per‑request payments using only HTTP headers and standard cryptographic signing, reducing credential overhead and enabling usage‑based pricing.

Рабочий процесс

• 1. Agent sends initial HTTP request to service.
• 2. Service responds 402 Payment Required with a Pay header describing amount, token, and payload.
• 3. Agent builds payload (request‑id|timestamp), signs concatenated fields with its private key.
• 4. Agent retries request adding Pay header with signature.
• 5. Service verifies signature and token balance, then returns 200 OK with resource.

Доказательства

Traditional monetisation (API keys, subscription tiers, or invoicing) forces the agent to carry static credentials, manage billing cycles, or wait for human‑approved invoices.

Источник

The x402 proposal (an extension of the HTTP 402 Payment Required status) solves this by turning payment into a first‑class HTTP concern.

Источник