hook.testtau.com — Webhook capture

POST, PUT, GET, anything — to https://hook.testtau.com/<hookId> and inspect every request live at https://hook.testtau.com/_/<hookId>.

Quick start

curl -X POST https://hook.testtau.com/my-hook-id \
  -H 'content-type: application/json' \
  -d '{"event":"hello"}'

What's captured

• Method, full path including subpaths and query string.
• Every header (except CF-internal ones).
• Client IP and country (from Cloudflare).
• Full request body, up to 1 MiB.

Configurable response

By default the hook responds with 200 {"ok":true}. Open the inspector and click ⚙ to change status code, body, or content-type — useful when testing how your sender handles a 4xx or 5xx.

Replay

Any captured request can be re-sent against another URL — handy for forwarding a recorded production event to your local dev environment.

Schema assertions NEW

Attach a JSON Schema to a hook and every captured request body is validated against it. Pass/fail shows up next to each request in the inspector, and a dedicated /assert endpoint returns 200 or 422 so CI can gate a build on it.

Setting a schema

Open the inspector at https://hook.testtau.com/_/<hookId> and click the Schema button. Paste a JSON Schema (draft 2020-12 or draft-07) and pick a fail mode:

• Record (default) — failing requests are marked red in the inspector, but the hook still responds with its configured 2xx. Use this when you want to observe without disrupting the sender.
• Reject — failing requests get an immediate 422 with the validation errors in the body. Use this when your sender has a retry policy and you want to force a fix.

Example schema

{
  "type": "object",
  "required": ["event", "user_id"],
  "properties": {
    "event": { "type": "string", "enum": ["signup", "login", "logout"] },
    "user_id": { "type": "string", "pattern": "^u_[a-z0-9]+$" }
  },
  "additionalProperties": false
}

CI gating

The /assert endpoint summarises the last N captures:

curl -fsS "https://hook.testtau.com/_/<hookId>/api/assert?since=$(date +%s%3N)&min_count=1"

Returns 200 with a JSON summary when all captures since the given timestamp passed (and there were at least min_count of them); returns 422 with the same summary otherwise. curl -f turns that into a non-zero exit code that fails the build.

GitHub Actions example

jobs:
  contract:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Trigger webhook sender
        run: ./scripts/fire-webhook.sh
      - name: Wait for capture + assert schema
        run: |
          START=$(date +%s%3N)
          sleep 10
          curl -fsS \
            "https://hook.testtau.com/_/<hookId>/api/assert?since=$START&min_count=1" \
            | tee assert.json

Limits

Reserved paths

Hook ids matching _, health, favicon.ico, robots.txt, admin, or api are reserved.