Guide

Boosts, explained

Boosts are Zen Browser’s built-in way to restyle one website: new colours, a different font, a calmer layout. Zen Boosts is an unofficial, community-run directory of boosts that other people made, ready to install.

What are boosts?

Since version 1.20, Zen Browser can change how any website looks without extensions. You open the boost editor on a site, play with a handful of controls, and Zen remembers the result for that site. A boost can combine any of these:

  • Colour. Drag the dots on the colour picker to tint the whole page. A second dot sets the accent that light colours lean towards, and Advanced Color Controls tune contrast, brightness and saturation.
  • Space colours. The tint can follow the colour of your active Zen Space, so the same boost looks different in each Space.
  • Smart Invert Colors. Flips light pages dark while keeping their hues, which makes it a dark mode for sites that lack one.
  • Font. Swaps the site’s typeface for one from Zen’s font grid.
  • Case. Forces uppercase, lowercase or capitalised text.
  • Size. Zooms the page to 90, 110, 125 or 150 percent.
  • Zap. Click parts of the page to hide them: sidebars, banners, feeds you never read.
  • Focus. Keeps only the elements you pick, centred, and hides everything else. Needs Zen 1.23.4 or newer.
  • Code. Your own CSS, for anything the buttons can’t do.

One boost, one exact site

A boost belongs to one exact host name. To Zen, www.youtube.com, youtube.com and music.youtube.com are three different sites, and a boost made on one does nothing on the others. Whether the address starts with http or https doesn’t matter. That is why every boost here shows the exact host it was made for.

A site can have several boosts, but only one is active at a time. You can switch between them, turn them off or delete them in the Boosts section of Zen’s Library.

Installing a boost from Zen Boosts

Every boost page has a Download .json button. Some also list the author’s Zen share link. Both end with the boost active on its site, but only the download is checked by Zen Boosts.

Any Zen with boostsChecked by us

Download .json

Always available. You download the boost as a file and import it with Zen’s Import Boost. It is exactly the boost the page shows, after our checks. Takes about a minute.

With the file: Download .json and Import Boost

  1. On the boost’s page, click Download .json and note the host the boost is for.
  2. In Zen, go to exactly that host. For a www.youtube.com boost that is https://www.youtube.com/, not youtube.com.
  3. Click the site icon at the left of the address bar, then its boost button: Create a Boost, or Create new boost before Zen 1.24. You can also run New Boost from the command palette. A fresh boost editor opens.
  4. Click the boost’s name at the top of the editor and choose Import Boost.
  5. Pick the .json file you downloaded.
  6. Close the editor with Esc, Ctrl+W (Cmd+W on macOS) or its close button. Zen saves the boost and applies it to the page.

Import into a fresh editor. Importing while you edit an existing boost replaces that boost’s settings. The page may not change until you close the editor.

With the author’s share link

Some boost pages end their install panel with Author’s Zen share link, a link to share.zen-browser.app. Opened in a normal Zen window, it makes Zen ask Add this Boost to Zen?, and Get Boost adds it and opens the site.

We can only check that the link is live and was shared for the same site under the same name, not what it installs. Zen cleans a shared boost’s custom CSS but not its Zap and Focus selectors. Use the link only if you trust the author; otherwise use the download. A link stops working 30 days after it was created, and we remove it when the author uploads a new version.

Making and exporting a boost in Zen

  1. Open the site you want to restyle in Zen 1.20 or newer.
  2. Click the site icon in the address bar, then its boost button (Create a Boost, or Create new boost before Zen 1.24), or run New Boost from the command palette.
  3. Make your changes: the colour picker, Smart Invert Colors, a font, Size, Case, Zap, Focus and Code.
  4. Click the boost’s name at the top of the editor and choose Rename Boost to give it a clear name.
  5. Click the name again, choose Export Boost and save the .json file. Zen confirms with “Boost exported!”.
  6. Close the editor. Zen keeps the boost and applies it.

Already made one? Open the Library, go to Boosts, right-click your boost and choose Export Boost. You can also open its editor there with Edit Boost.

Zen throws away a boost that has no changes when you close its editor, so make at least one change before you export. The exported file doesn’t say which site it is for: you tell us the host when you submit.

Getting a share link

In Zen 1.24 and newer, the editor has a Share button at the bottom. Click it, check the name and preview, then choose Share Boost. Zen copies a share.zen-browser.app link to your clipboard. Paste it into the share link field when you submit, and your boost page lists it for the next 30 days, marked as not checked by us. Share under the same name you give the boost here. A share link is a snapshot of one version: when you upload a new version, the old link is removed, so share again and add the new one.

Submitting a boost

Sign in with GitHub, choose Submit a boost, upload your exported .json and enter the host it was made on. A good submission has:

  • A clear name that says what it does, like “Calm Tube” or “Old Reddit, Gently”. Up to 80 characters.
  • An honest description. Say what changes and what gets hidden, and mention anything people should know first: it follows your Space colours, it needs a font you may not have, it hides the comment box.
  • A screenshot of the site with your boost on (PNG, JPEG or WebP, up to 3 MB). Without one, we draw a colour preview from the boost’s settings.
  • A few tags (up to six), such as dark-mode, minimal or reading, so people can find it.
  • The right host: exactly what your address bar showed while you made it, with or without www.

Please don’t submit:

  • Someone else’s boost as your own. Credit the original author in the description if you remix one.
  • Boosts that mislead: fake buttons or overlays, hidden warnings, or anything that makes a site look like a different one.
  • Ads, spam, or many near-identical copies of the same boost.

Identical settings for the same host can only be submitted once, and each account can add up to ten boosts a day. You can update a boost later from its page by uploading a new export; we keep its last ten versions.

Safety

Boosts only change how a page looks. They can’t run scripts or read what you type. CSS can still fetch things from the web, though, which could tell a server which pages you visit, and Zen installs an imported file exactly as it is. So we check every upload before anyone can download it from us:

  • Only the settings Zen itself uses are kept. Numbers are range-checked, text is cleaned, and files over 256 KB are refused.
  • Custom CSS is read with a real CSS tokenizer. Anything that could reach the network is refused: url(), image-set() and similar functions, @import, @namespace, web fonts other than local() ones, and backslash escapes that try to hide those words. So is -moz-binding.
  • Zap and Focus selectors must parse as plain CSS selectors, with no braces, semicolons, at-rules or comments. Zen inserts them into a stylesheet as they are, so this matters.
  • Font names follow Zen’s own rules, and site names are checked the same way Zen checks a shared boost’s domain.
  • Every download is rebuilt from the checked settings, never served from the raw upload.
  • Screenshots must really be PNG, JPEG or WebP images (we check the bytes, not the file name). SVG is not accepted.
  • Submitted CSS never runs on this site. Code and selectors are only ever shown as text.

These checks cover the Download .json file. An author’s Zen share link is not covered: Zen’s share server keeps a share’s contents private, so we can’t inspect it, and it may differ from what the page shows.

A boost can still hide or rearrange parts of a page, which is the point of most boosts. Read the description and the settings on the boost’s page before you install, and remember that authors are GitHub accounts, not verified publishers.

Found something broken, misleading or malicious? Use Report this boost on the boost’s page. Moderators review every report and remove boosts that break the rules.

FAQ

Is this an official Zen site?

No. Zen Boosts is run by members of the Zen community. It isn’t made, endorsed or reviewed by the Zen team, and boosts here come from other users, not from Zen.

The Zen team may offer an official way to find and share boosts in the future. If that happens, we’ll point you to it. Until then, this is a place for the community to share what they’ve made.

Why does my boost only work on www.?

Zen ties a boost to the exact host it was made on. A boost made on www.example.com doesn’t apply to example.com or to any other subdomain. If a site answers on both, make a boost on each host, or install the boost from the host the page lists.

Why did the share link expire?

Zen’s share server keeps links for 30 days, and sharing the same boost again returns the same link without extending it. The Download .json button never expires. Authors can share again in Zen once the old link has expired and add the new link by editing their boost here. Uploading a new version also removes the link, since it still points at the old one.

The page is still zoomed after removing a boost?

Size works through the browser’s page zoom, the same zoom as Ctrl++. The browser can remember zoom per site, so the level may stay after a boost is turned off or deleted. Press Ctrl+0 (Cmd+0 on macOS) on that site to reset it.

Fonts look different on my computer?

A boost stores a font name, and your computer has to have that font. Zen’s font grid also picks different fonts on different systems: the same choice can be Avenir on macOS and Nunito or a plain sans-serif on Linux. If a font is missing, the browser falls back to a similar one.

Can I edit a boost after sharing it in Zen?

Not the share link. Zen warns that you won’t be able to edit a shared boost: changes you make later only apply to your own copy. On Zen Boosts you can: open your boost, choose Edit and upload a new export. Its version number goes up. People who installed an earlier version keep their copy until they import the new one.

How do I turn a boost off or remove it?

Open Zen’s Library and go to Boosts. Each boost has a toggle to enable or disable it and a delete button; right-click for Delete Boost. You can also switch boosts from the site icon in the address bar.

Do boosts work in other browsers?

No. Boosts are a Zen Browser feature. Get Zen to use them.

Credits and disclaimer

Unofficial community project. Not made, endorsed or reviewed by Zen Browser or the Zen team. Zen Boosts is built by volunteers from the Zen community. “Zen Browser” and its logo belong to their owners. The Zen team may offer an official way to find and share boosts in the future. Until then, Zen Boosts is a community-run place to share them.