Scrolling
The color follows the page.
Vitrel reads the top left corner of the page and repaints the tabs and toolbar when it changes. Scroll the article and the color follows.
Scroll inside the window, or pick another tab.
A web browser for the Mac
As efficient as possible. No exceptions.
Vitrel is a small browser built to use as little of your Mac as it can. It runs on the WebKit already in macOS, its tabs and toolbar use no CPU while idle, and it blocks ads and trackers by default.
Why it's efficient
Mac only. Private beta soon.
Why it's efficient
Four decisions, all pointing the same way.
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01In the app
No engine of its own.
Vitrel runs on the WebKit that ships with macOS, the engine Safari uses. It bundles no copy of WebKit or Chromium, so it gets Apple's power tuning, hardware video decoding and memory handling, and engine updates arrive with macOS.
0browser engines bundled
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02Measured
Zero CPU when idle, as a hard rule.
The tabs, toolbar and address bar run no timers, no polling and no idle animations. They do work only when you or the page do something. Even the toolbar's page color updates on events, never on a timer.
App process, idle with a new tab, three tabs or Wikipedia open. In a 3 second sample, all 2,672 main-thread samples were waiting for events. M5 MacBook, macOS 27.0, 30 Sep 2026.
0.00%app CPU while idle
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03Measured in testing
Blocking built in, on by default.
Vitrel compiles the standard filter lists into WebKit's own content rules. There's nothing to install or switch on, and a blocked ad or tracker is never downloaded, parsed or run.
EasyList, EasyPrivacy, uBlock Origin's filters and privacy list, and Peter Lowe's list, fetched 30 Sep 2026; 94.8% of their filter lines convert. The blocker is built and tested on its own, and moves into the app before the beta.
141,148WebKit rules from five lists
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04Planned
Tabs that sleep, and a lazy restore.
Tabs you haven't looked at in a while will sleep: Vitrel keeps the address, scroll position and history, frees the page, and loads it again when you come back. Tabs playing audio, pinned tabs and half-filled forms stay awake. At launch, only the tab in front will load.
Comingnot built yet
Blocking, measured
Less to download, less to wait for.
Eight news sites, each loaded with Vitrel's blocker off and on. Pick a site to see its requests.
Median time to load 946 ms with the blocker, from 1,938 ms without
Time to load
Requests, yahoo.com
46% fewer requests. 372 with the blocker off, 202 with it on. One dot per request.
How it was measured: M5 MacBook (10 cores, 24 GB), macOS 27.0, 30 Sep 2026. Vitrel's blocker in a WebKit test harness, all five lists and its scriptlets, against no blocking. Every load in a fresh web view with an empty cache and Safari's user agent, median of three loads, timed to WebKit's didFinish. On bbc.com blocking was 127 ms slower, within network noise at three runs. The eighth site, dailymail.co.uk, served a consent page (1 request either way); it counts toward the median but isn't drawn.
All eight sites as a table
| Site | Load, off | Load, on | Requests, off | Requests, on |
|---|---|---|---|---|
| cnn.com | 1,613 ms | 1,412 ms | 142 | 97 |
| forbes.com | 5,738 ms | 967 ms | 250 | 110 |
| weather.com | 5,085 ms | 688 ms | 361 | 100 |
| huffpost.com | 6,130 ms | 955 ms | 250 | 90 |
| yahoo.com | 1,813 ms | 937 ms | 372 | 202 |
| theverge.com | 2,064 ms | 1,542 ms | 340 | 167 |
| bbc.com | 600 ms | 727 ms | 107 | 86 |
| dailymail.co.uk (consent page) | 528 ms | 487 ms | 1 | 1 |
| Median | 1,938 ms | 946 ms |
And it looks like the page
The toolbar takes the page's color.
Vitrel paints its tabs and toolbar in the color at the page's top left corner, so the page and the browser read as one surface. Same rule as everything else: the color changes only when the page does, and working out a new palette takes about 7 microseconds.
Median, Release build, M5 MacBook, macOS 27.0, 30 Sep 2026.
Sidebars
It starts where sidebars start.
That corner is where documentation and app sidebars sit, so a dark sidebar carries straight up into the toolbar.
Contrast
Exact color, readable text.
The page color is copied as it is. Only the text changes, switching between dark and light to stay legible.
Dark pages
No line under the toolbar.
There's no border or inset around the page. When a site is dark, the whole window is dark.
Vitrel is in development.
Mac only. macOS 15.4 or later. Private beta soon.