Definition
x402 is a 2025-2026 payment protocol that repurposes the long-unused HTTP 402 status code for programmatic micropayments on Base, letting AI agents pay per API call instead of relying on prepaid credits.
In Depth
The x402 protocol emerged from the Coinbase and Base ecosystem and surpassed 119 million transactions as of early 2026. The idea is simple: a server that needs payment returns HTTP 402 with a challenge; a client (usually an agent with a USDC wallet) pays on-chain and retries. No API key, no prepaid credits, no per-tenant key juggling. Scavio supports x402 alongside traditional API-key auth for agents that prefer on-demand billing.
Example Usage
A multi-tenant AI agency routed client agents through x402 so each tenant's usage settled on its own wallet instead of the agency's shared API key.
Platforms
x402 is relevant across the following platforms, all accessible through Scavio's unified API:
- Amazon
- YouTube
- Walmart
Related Terms
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