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TallyPay

TallyPay documentation

Welcome. These docs are written for application developers who want machine-to-machine or user-assisted payments over HTTP—not for speculators.

What you’ll find here

  1. x402 fundamentals — what the protocol is, how HTTP 402 is used, and how a facilitator fits in.
  2. Hands-on path — Express + React using the open-source @tallypay/* packages (middleware + client hooks).
  3. TallyPay product — how our hosted layer adds traces and conversion insight (the “why sign up” part).

We bias toward stablecoins on EVM-style networks (e.g. USDC on Base) because that’s where most facilitator tooling is mature today; the concepts transfer as more chains and facilitators adopt x402.

If something here is wrong or outdated, let us know via tallypay.dev—we want this to be the clearest x402 reference on the web. (GitHub issues and PRs will be welcome once the repo is public at launch.)