Causeway Services — page 2

Ordered by date created, newest first. Page 2 of 2; 18 publications total.

• What does HTTP 402 Payment Required mean? A history of the web's unused code 2026-09-29 · article
  HTTP 402 Payment Required was reserved in the web's standard in the 1990s and left unused for decades. Its history, why micropayments failed, and what changed.
• Who built x402 and who governs it? From Coinbase to the Linux Foundation 2026-09-29 · article
  Coinbase released x402 in May 2025; the Linux Foundation's x402 Foundation launched 14 July 2026 with 40 members. Timeline, members, and what it doesn't govern.
• x402 glossary: 44 terms for HTTP 402, agent payments and USDC 2026-09-29 · page
  Plain definitions of x402, HTTP 402, facilitator, EIP-3009, CAIP-2, USDC, MCP, A2A, AP2, MPP, L402, calls per payer and more, each with its first-use context.
• x402 security: risks and defenses for AI agent buyers and API sellers 2026-09-29 · article
  Spending limits outside the model, payments bound to requests, settle before delivery: what 2026 research found wrong with x402 and how to defend.
• What happens when you sell an API on x402? Lessons from the Bazaar and one small seller 2026-09-27 · article
  Median x402 price: one cent. A few sellers earn nearly everything. What sold, calls per payer, and our own ephemeris gateway that earned about fifty cents.
• x402 vs MPP, AP2, ACP and L402: agent payment protocols compared 2026-09-27 · article
  x402, MPP and L402 let one HTTP request carry its payment; AP2 and ACP prove a person approved a purchase. Each protocol sorted by the question it answers.