Free Online Request Catcher & Webhook Tester
Capture and inspect HTTP requests and webhooks instantly. MockFlow's online request catcher gives you a unique endpoint URL where you can receive requests and inspect their headers, query parameters and body.
A free account is required for a public URL. No credit card.
How the Request Catcher Works
- 1
Create a free account and a request catcher endpoint in a project.
- 2
Copy the generated public URL.
- 3
Send an HTTP request or webhook to that URL.
- 4
Inspect the incoming request in MockFlow — then replay it to another public HTTP or HTTPS URL if you need the same payload again.
Try it with curl
After you create a catcher, replace the placeholder with your endpoint URL and send a request. The payload appears in the inspector so you can review headers, query parameters, parsed JSON, and the raw body.
curl -X POST "YOUR_MOCKFLOW_REQUEST_URL" \
-H "Content-Type: application/json" \
-d '{
"event": "payment.completed",
"id": "evt_123"
}'HTTP Request Catcher
Use MockFlow as an HTTP request catcher for any incoming request. GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS are captured on the same endpoint. You can inspect headers, query parameters, JSON bodies, and raw bodies (including form-urlencoded payloads stored as text).
Method & path
Exact HTTP method and URL path, including the query string.
Request headers
Every header the caller sent. Sensitive values can be masked.
Query parameters
Search params parsed into key-value pairs.
JSON and raw body
Valid JSON is shown as a tree. Other types keep the raw text.
Request history
Captured requests stay on the catcher so you can reopen them later.
Replay
Re-send a captured request to another public HTTP or HTTPS URL.
Webhook Catcher
Webhook catching is the same request catcher used for callbacks. Paste the URL into a provider and inspect the event it actually sends — including signature headers — before you write a handler. MockFlow is not an official integration for any provider; any service that can POST to an HTTPS URL can use it.
- Payment provider webhooks
- SaaS callbacks and CRM events
- GitHub and similar repo webhooks
- Automation platforms and third-party APIs
Each catcher can return a configurable JSON response body (HTTP 200). Custom status codes, response headers, and delays belong to mock API endpoints in the same project, not the catcher itself.
Request Catcher Online
With an account, the catcher URL is a public cloud endpoint. You do not need to run a local server, expose localhost, or stand up a temporary backend just to see what a client sends. Guest mode is different: it keeps mock APIs in localStorage and never issues a public catcher URL.
URLs persist on the project, so providers can keep sending events after you close the tab. Standard plan history is 7 days by default and can be changed in project settings.
When teams use it
Before the handler exists
Point the provider at MockFlow, collect real requests, then replay them to a public staging URL when your handler is ready.
Debugging third-party traffic
See the headers, content-type, and payload a CRM, payment API, or SaaS tool actually sends — not only what the docs claim.
Sharing a captured request
Copy JSON or headers so a teammate can reproduce the same event, or replay the request to a public target URL.
Comparing throwaway bins? See the RequestCatcher.com alternative guide.
Request Catcher FAQ
What is a request catcher?
A request catcher gives you an endpoint URL that receives HTTP requests so you can inspect what was sent — method, headers, query parameters, and body — without writing a server first.
How do I capture an HTTP request online?
Create a free MockFlow account, open a project, and add a Request Catcher. Copy the public URL, send any HTTP request or webhook to it, then open the inspector to view headers, query parameters, parsed JSON, and the raw body.
Can I use MockFlow as a webhook catcher?
Yes. Point a payment provider, GitHub webhook, SaaS callback, or automation platform at the same catcher URL. MockFlow captures the incoming POST (or any other supported method) so you can inspect the payload and replay it later.
Can I inspect HTTP headers and request bodies?
Yes. Every captured request shows all headers (sensitive values can be masked), parsed query parameters, a JSON tree when the body is valid JSON, and the unmodified raw body for other content types such as form data.
Do I need an account?
Yes, for a public request catcher URL. Incoming HTTP from the internet has to hit a cloud endpoint tied to your project. Guest mode stores mock APIs in browser localStorage and does not create public catcher URLs.
What HTTP methods can I capture?
MockFlow captures GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS on the catcher URL.