JPYC ASCII Art
JPYC（日本円コイン）のASCIIアート。x402 + JPYCで決済するコンテンツのサンプル。
Adding JPYC on Polygon as a Payment Option for x402
How we added a non-USD stablecoin on a non-Base chain to an x402-protected API — custom facilitators, multi-option 402 headers, and cross-chain revenue tracking.
Autonomous Payment Security: How to Build x402 Agents That Don't Get Drained
Self-paying AI agents are powerful but carry real financial risk. This article covers the attack vectors, trust boundaries, and practical patterns for keeping autonomous wallets safe.
openapi.json for AI Agents: How Payment Discovery Actually Works
robots.txt tells crawlers what to access. llms.txt tells agents what your site means. openapi.json tells agents what your API costs and how to pay. Here's how to write one that works — including the warnings that won't show up in the docs.
x402 Chain Fragmentation: Why Base Is Winning and What It Means for Developers
x402 has been implemented on a dozen chains, but the ecosystem is rapidly converging on Base. Here's the data, and why it matters for anyone building paid APIs.
x402 From Zero to Paid Endpoint in 30 Minutes
The docs are sparse and the SDKs are young. Here's the concrete path from nothing to a working x402 endpoint — including the parts that aren't documented anywhere.
x402 Server-Side Security: Replay Attacks, Verification, and What to Log
Client-side x402 security gets most of the attention. Server-side is where the real edge cases are: verify before settle, duplicate payment detection, idempotency keys, and building an audit trail that holds up.
How AI Agents Discover and Pay for APIs Without Human Intervention
No UI required. AI agents find paylog.dev through openapi.json, llms.txt, and Bazaar — then pay automatically via x402 or MPP. Here's how the discovery-to-payment flow works.
How to Configure robots.txt for AI Crawlers
A practical guide to configuring robots.txt for AI crawlers. Learn which bots to allow, which to block, and how to use Content-signal.
Monetize AI Crawlers with x402 Instead of Blocking Them
Instead of blocking AI training bots, charge them via x402. Turn crawls into revenue with no API keys or billing integration required.
paylog.dev now supports x402 on Base
After MPP on Tempo, paylog can now track USDC spend on Base via the x402 protocol. New endpoints, CLI flags, and what changed under the hood.
What is llms.txt and Why Your Site Needs One
llms.txt helps AI agents understand your site. Learn how to create one and what to include.
8 Things That Tripped Me Up Implementing x402
Technical pitfalls I hit while building Base chain USDC spend tracking — facilitator differences, EIP-3009 internals, an empty service map, and more. Available for AI agents via x402 ($0.01 USDC on Base mainnet).
The 402 Hack Explained
How paylog uses HTTP 402 error responses as a data source to map on-chain payment addresses to service names — without ever making a real payment.