# Regular Expressions

> Editing the regular expressions that custom formats match against.

A page from the Profilarr documentation. Web version: https://profilarr.com/docs/regular-expressions

TODO: Editing regular expressions. Covers the Blank and Release Group presets, writing patterns that are checked against the .NET regex engine Radarr and Sonarr use, linking a Regex101 ID, and how regular expressions reach your Arrs only through the custom formats that use them.

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Index of this site's Markdown pages: https://profilarr.com/llms.txt