HTTP Catcher
Responses
Choose how a bin answers, with a default reply and rules by method and path with templated bodies, delays and failure rates.
Try it in the demo.
Each bin answers every request. The answer decides what your app sees: success, a rate limit, a server error, or a slow reply that hits your timeout.
What it solves
- Your app's retry and backoff code never runs, because the real API rarely fails.
- Your app needs a realistic answer (a message id, an
ok: true) to carry on. - You want to know what happens when a partner API takes 5 seconds.
How a bin chooses its answer
- The rules are checked from the top; the first match wins.
- With no match, the Default reply is sent (the preset's reply, or
200 {"ok":true}). - A rule with a failure rate answers with its failure status that share of the time ("Simulated failure").
The Response tab of each captured request says which one answered.
The Responses tab
Open a bin and the Responses tab:
- Rules in order, with move up and down, an enabled switch, a summary such as "POST /v1/* when header x-env is test: 429 after 0.5 to 2 s, 10% fail with 500", and edit and delete.
- Default reply with Edit default reply.
- Add rule opens the rule sheet.
The rule sheet
| Part | What to set |
|---|---|
| Name | what the rule is for, for example "Quota exceeded" |
| Match | the method (any or one), a Path glob relative to the bin (/v1/*), and header or body conditions with the same builder as webhook rules |
| Response | Status code, headers and body, written as templates |
| Delay | fixed, or a random range in milliseconds (up to 30 s) |
| Failure rate | 0 to 100%, with the status code a failure returns |
| Preview | against a captured request of the bin: whether this rule matches it (and why not), and the rendered status, headers and body |
Templates can read the request: request.method, request.path, request.query, request.headers, request.body, request.json, plus vars and the template functions, for example:
{ "id": "{{ uuid() }}", "received": {{ request.json.text | tojson }} }Step by step, with examples: Advanced: catcher responses.