Summary
Jan Černý, founder and CEO of Apify — the largest marketplace of AI tools with roughly 45,000 actors and over $1 million in monthly community payouts — delivers a technically grounded critique of the x402 agentic payment protocol at AI Engineer World’s Fair, modeled deliberately on a 2025 talk titled “MCP isn’t good yet” that preceded MCP becoming a dominant industry standard.
Černý is bullish on x402’s long-term potential and just launched Apify’s own x402 integration with Coinbase two days before the talk, adding 20,000 tools and roughly 10x-ing the total size of the x402 agentic marketplace. But he argues the protocol has real rough edges that builders need to understand. Most notably, the x402 spec enforces an HTTP 402 response from the server, while MCP Auth requires HTTP 401 — a direct conflict between two standards that are supposed to work together. He also details a double-spending vulnerability: because settlement happens on-chain after the work is done, a client can create thousands of signatures against the same wallet balance before any transaction is confirmed, effectively skipping out on payment for non-trivial workloads.
The talk surveys the broader agentic payments battleground, cataloguing over a dozen competing standards from MasterCard Agent Pay, Visa KY Pay, OpenAI’s ACP, Google’s API2, Stripe’s MPP, and others, arguing the space is a heated battleground for capturing future agentic transaction volume. Černý’s thesis: x402 is the right foundation, but needs another year of hardening similar to what MCP underwent.
📺 Source: AI Engineer · Published September 01, 2026
🏷️ Format: Opinion Editorial
