Available inall subroutines.

Returns the given URL without the listed parameters.


set req.url = querystring.filter(req.url,
"utm_source" + querystring.filtersep() +
"utm_medium" + querystring.filtersep() +

Try it out

querystring.filter is used in the following code examples. Examples apply VCL to real-world use cases and can be deployed as they are, or adapted for your own service. See the full list of code examples for more inspiration.

Click RUN on a sample below to provision a Fastly service, execute the code on Fastly, and see how the function behaves.

Create image transform presets

Use custom, predefined classnames like large, medium, small, teaser, thumb, or article to control Fastly Image Optimizer and optionally prevent end-user access to native properties like 'width'.

Send HTTP Basic Auth in request to origin

Convert a password sent by the client in the querystring into a Authorization header to your origin server.