x402 isn’t good (yet) — Jan Curn, Apify
The talk critiques current standards for agentic payments, arguing that while protocols like x402 are exciting, they suffer from significant architectural flaws, particularly regarding double spending and standardization conflicts. The speaker highlights the rapid proliferation of payment standards (L402, MasterCard Agent Pay, etc.) and proposes solutions such as batch settlement and a new 'Agent General Interface' (AGI) to facilitate robust, flexible agent-to-agent commerce.
Key takeaways
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x402 Status Code Flaws
7:59
The x402 protocol requires the server to respond with HTTP 402 Payment Required. This conflicts with other standards (like MCP requiring 401), forcing companies to create dedicated hostnames for payments, which the speaker calls an anti-pattern.
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The Double Spending Window
10:19
A critical vulnerability in current payment flows is that until a transaction settles on the blockchain, the buyer can use the same funds for multiple transactions (double spending). This risk makes non-trivial work difficult to guarantee.
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Need for Flexible Interfaces
17:15
To avoid creating new endpoints or rigid API changes, the speaker introduced AGI (Agent General Interface), a simple markdown document designed for agents rather than humans. This allows services to adapt quickly without requiring strict backward compatibility.