How to edit and replay HTTP requests

VioLens gives you three ways to change what gets sent: pause a live request and edit it, send a captured request again, or write a request yourself. If you've used Fiddler Classic, these are its breakpoints, Reissue and Composer.

All of them work while VioLens is capturing, so click Start first.

Change a request while it’s in flight

Check Tools > Also Break On and enter some text from the URL in URL contains. Or type bpu /api/orders in the QuickExec box under the session list.
Do whatever sends the request. It stops and appears in the Breakpoints panel.
Select it to see the raw request: the first line, the headers and the body, as text you can edit.
Change what you need to, then click Resume to send it, or Abort to drop the connection.

To change a response before the browser gets it, use Break on Responses, or bpafter text in QuickExec. Type go to let everything that’s paused carry on, and bpu on its own to stop pausing.

Send a captured request again

Select a session and press R, or choose Edit > Replay Selected Session. VioLens sends the same request again, byte for byte, and the result shows up as a new session. It’s handy for checking whether a fix worked, or whether a failure happens every time.

Edit a captured request and send it

Select a session and choose Edit > Edit in Composer. The request opens in the Composer tab as raw HTTP. Change the URL, the headers or the body, and click Execute.

You can also write a request from scratch:

POST https://api.example.com/items HTTP/1.1
Content-Type: application/json

{"name": "test"}

For bodies that aren’t text, such as images or protobuf, set Body to Hex or From a file.

See what changed

To compare the request that works with the one that doesn’t, select both (Ctrl+click, or Cmd+click on a Mac) and press Ctrl+W. VioLens shows them side by side, with the differences highlighted.