Available in all 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 solution recipes, which show real world use cases. Click RUN to provision a Fastly service, execute the code on Fastly, and see how the function behaves.

Image transformation classes

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.

User contributed notes

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