The open-source example project: an agent that pays for its own data
Build an autonomous data agent that pays for its own data using open-source tools like @harpd/mcp-paid-tool-starter and local budget policies. Step-by-step integration overview.
Blog
Building Harpd
Product, engineering and operating notes from the Harpd team.
About this category
Engineering and operating notes from building Harpd itself. These posts cover the decisions behind the platform — how ranking is computed, how the data pipeline is kept within a free-tier budget, how pages are made verifiable and how claims are traced back to evidence. Written for readers who want the implementation, not the pitch.
x402 in practice: charge-per-call from zero to first payment
An end-to-end x402 tutorial — set up a paid endpoint with HTTP 402, charge 0.01 USDC per call, observe every payment with the open-source SDK, and verify settlement onchain. No Harpd account required to follow along.