Using x402check in CI with the GitHub Action

If you sell through x402, silent drift is the boring kind of outage. Your live 402 starts asking for a new price or a new payTo, the directory still shows the old numbers, and agents fail or pay the wrong wallet until someone notices.

The x402check Endpoint Preflight GitHub Action runs the same checks in CI on a schedule or on push.

What it does

For each URL you list, it calls x402check and compares:

• priceUsd
• payTo
• network

…to either explicit expected values or a baseline file from the last good run. Mode fail breaks the job. Mode warn only annotates.

Minimal workflow

name: x402 seller preflight
on:
  schedule:
    - cron: "0 */6 * * *"
  workflow_dispatch:

jobs:
  check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: nwilliams005/x402check-action@v1
        with:
          mode: fail
          payer-private-key: ${{ secrets.X402CHECK_PAYER_KEY }}
          endpoints: |
            [
              {
                "url": "https://your.example/api/tool",
                "expectedPriceUsd": 0.01,
                "expectedPayTo": "0xYourPayTo",
                "expectedNetwork": "eip155:8453"
              }
            ]

Store the payer key as X402CHECK_PAYER_KEY. Fund it with a little USDC on Base. The Action will try the one free regular check per wallet first, then pay $0.01 (or $0.05 if you set deep: true).

Baseline mode

If you omit expected*, the Action compares to .x402check-baseline.json and can rewrite it after a clean run (write-baseline: true). That is handy when prices are intentional but you still want to catch surprise changes.

Pair with watch

CI catches drift when GitHub runs. For email when price or payTo changes between runs, use the $5 / 30 day watch on x402check.dev.

Pinning

Marketplace listing: x402check Endpoint Preflight. Pin @v1 or a commit SHA. Source: nwilliams005/x402check-action.