Callback assertions

A callback assertion passes when a request’s send causes a webhook. After the send, Wirebench waits for a capture at one of the workspace’s catch URLs, takes the first one that fits, and checks it.

Add one

1. Point the system under test at a catch URL of the server workspace, for example orders-hook.
2. In a sequence step, choose Add assertion, then Callback.
3. Choose the Catch URL and how long to wait in Within (s): 1 to 300 seconds, 30 by default.
4. Narrow which capture counts: a Method, a Path (exact, or a pattern with Regex), headers, a body value.
5. Add what is checked on it under Expect: a body value, a header, or Signature verified.

Only captures that arrive after the send count. When a step runs twice, the second run never reuses the first run’s callback.

assertions:
  - type: callback
    catchUrl: orders-hook
    withinMs: 30000
    match:
      method: POST
      path: /events/order-paid
      body: { language: jsonpath, path: $.orderId, equals: '${#Sequence#orderId}' }
    expect:
      - body: { language: jsonpath, path: $.status, equals: paid }
      - signature: verified

equals and matches values expand properties like the values of other assertions do: a value an earlier step transferred, an environment property, ${#System#…}. Names, paths and the method are used as written. An expanded value can appear in a failure message, so keep credentials out of callback assertions.

What the result says

Result	Message
Passed	matched capture 01K… after 2.0 s
Failed	matched 01K…, but $.status: expected "paid", got "failed"
Failed	no capture matched within 5 s — 2 arrived; closest: POST /events/refund (path differs)
Failed	no capture arrived at orders-hook within 5 s
Errored	the workspace has no server, or no catch URL has that name

While a step waits, its row in the run panel reads waiting for orders-hook… (up to 30 s). In the desktop app, Show capture opens the matched capture in its catch URL tab.

In CI

wirebench run checks callbacks when WIREBENCH_SERVER_URL and WIREBENCH_SERVER_TOKEN are set. The token is a CI token. An editor or admin creates one with Create CI token… in Preferences → Devices & tokens. It is read-only and belongs to one workspace: it can read that workspace’s catch URL list and captures, and nothing else. Without the two variables, the request still runs and each callback assertion is reported as errored (exit code 3). See Run in CI.