Untch docs

Start here

Untch documentationQuickstartWhat Untch is

Concepts

SpendIntentPolicyPreflightEnforcement modesReceipts and proofTrust Bureau

For operators

DashboardPolicies (operators)EscalationsControl channelsVault

For agents

ASP overviewASP toolsx402 paymentsUntch GuardLifestyle and Launch Pack

Reference

NetworksContractsPricingErrors

Security

InvariantsThreat model

Operator-authorized payment middleware for x402 flows.

Untch Guard

Package: @untch/x402-guard

Mode B middleware for buyer agents. On each 402 challenge it:

  1. Parses the challenge
  2. Runs Challenge Binding Check (expected vs presented fields)
  3. Calls Untch preflight (or your preflight adapter)
  4. Invokes your signAndPay only if checks pass

Install

npm install @untch/x402-guard

Mental model

You keep the key. The guard keeps the agent from signing a challenge that was swapped, replayed, or never preflighted.

Binding failures map to BLOCKED_REPLAY or REJECTED_BINDING semantics. They never reach the signer.

Related