x402: How AI Agents Pay for API Calls with HTTP

Every second, AI agents hit rate limits, quota caps, and "payment required" errors that kill their workflows. They can reason about complex problems but can't pay a $0.02 API fee. Meanwhile, human developers juggle credit cards, subscription billing, and manual account management just to keep their agents running. The bottleneck isn't intelligence — it's payments. AI agents need economic agency to participate in the digital economy, and that requires wallet infrastructure designed for autonomous operation, not human oversight. Why Payment Infrastructure Matters for AI Agents Today's AI agents are economically dependent. They consume APIs through human-managed accounts with pre-funded credits or monthly subscriptions. When quotas run out, agents stop working until humans intervene. This breaks the promise of autonomous AI. The problem compounds as agents become more sophisticated. An autonomous trading agent might need to: Pay for real-time market data from multiple providers Purchase c