Firefox

Shake to Summarize

Platform
iOS

Stage
Enterprise

Deliverables
Product design, Prototyping, AI prompt engineering

Firefox on iPhone showing a bulleted summary of a Reuters article

Mozilla wanted more people to download Firefox. We gave them a reason: shake your phone, and any page becomes something you can actually read.

Exploration of the shake animation visual.

Four Firefox iPhone screens testing shake effects: AI space, cracked glass, fire glow
Three reactions. An AI space took you off the page. Cracked glass read as broken. Firefox’s fire kept the page in view and felt like Firefox.
Four Firefox iPhone screens with the glow on the frame, toolbar or address bar
Where the fire lives. Around the frame, the toolbar, the URL bar, or just inside the address field.
Four Firefox summary screens on teal, orange, navy and red-to-purple backgrounds

What the summary sits on.

Teal, fire orange, deep navy, and a red that fades into purple.

Three Firefox summary screens: full text, tl;dr bullets, and the Full toggle

How the summary reads.

Sections or bullets. A quick tl;dr or the full summary. Checked on news, shopping, and how-to pages.

The glow won.

We mapped every beat from the shake to the summary, then tuned it frame by frame with a design engineer.

Shake to Summarize 30 fps
Title text
Body text
Summarizing…
Border in
Border color
Border expand
Web page
Page drop
Page pulls up
Background
00:00:00
Typewriter
Fades in
Summarizing…
From edge
Web page
Page drop
Linear fill
Dark bg
0s1s2s3s Shake

Blur into the glow.

Drop the page.

Onboarding for the hero feature. We tried four ways to introduce the shake, from loudest to quietest, and went with a tooltip.

Full-screen Firefox intro with a hand shaking a phone above the explanation
Full-screen takeoverHard to miss. Stops your reading cold.
Banner over a Reuters article asking to summarize any page by shaking
Banner over the pageCovers what you came to read.
Firefox address bar reading “Summarize this?” below a Reuters article
The address bar asksReads like the page changed.
Tooltip above the Firefox toolbar: shake your device to summarize the page
A tooltipEveryone knows it. Our pick.

A bolt button for everyday use. It sits where reader mode used to, and we kept it free of the AI sparkle because Firefox users are wary of AI.

Firefox address bar with a bolt inside stacked page icons beside the microphone
“Little busy”
Firefox address bar with a plain outline bolt icon beside the microphone
“Interesting”
Firefox address bar with a plain page icon beside the microphone
“Standard”
Firefox address bar with a bolt inside a filled square beside the microphone
“Battery indicator”
Firefox address bar with a page icon and a blue plus sign
“Add to reading list”
Firefox address bar with a page icon and a blue notification dot
“Something is new here!”
Firefox address bar with a page icon and a small blue bolt
“Fine, but the icon is tough to understand”
Firefox address bar with a page icon and a small red bolt
“Feels like an error”

Ask first. Say what’s happening.

Summarizing sends the page to an AI model. For a privacy browser, that’s a big ask.

Four Firefox opt-in sheets asking to summarize an Allrecipes page, with Continue
The opt-in. Written with Mozilla’s legal team. It says plainly that the page goes to a third party. In the EU, it names the AI.
Six Firefox opt-in variants on red, asking to summarize an Allrecipes recipe
The wording. Six versions of the opt-in, from “Summarize this page?” to “You just shook your device!”

If the summary’s bad, the feature’s dead.

So we owned the prompt. Mozilla picked the model, Mistral Small 3.1. We tested every version in two loops: a fast one with no build, and TestFlight builds Mozilla’s team used on whatever they were reading.

Prompt v1 Fast test, no build Real page recipes, news Reader Mode pulls the page Mistral summarizes Bad Good tweak it, test again TestFlight new build Mozilla’s team tests it # mobile-testing TestFlight 11:08 AM New build · prompt v4 ✅ 3 👀 2 TestFlight 4:52 PM New build · prompt v4 ✅ 5 🔥 2 their feedback shapes the next prompt
Prompt v1 Fast test, no build Real page recipes, news Reader Mode pulls the page Mistral summarizes Bad Good test again TestFlight new build Mozilla’s team tests it # mobile-testing TestFlight 11:08 AM New build · prompt v4 ✅ 3 👀 2 TestFlight 4:52 PM New build · prompt v4 ✅ 5 🔥 2 feedback
  • Short enough to read at a glance
  • Gets recipes exactly right
  • Useful on any kind of page
  • Clean formatting
Rows of yellow notes, each a numbered version of the summarizer prompt

TIME

Best Inventions 2025

Awarded

Android

Plus more languages

Future additions
Collage of press coverage of Firefox Shake to Summarize, including TIME and MacRumors

Even the skeptics came around.

Our users were wary of AI and of shake gestures. Months after launch, this showed up on r/firefox.

I actually love the Firefox shake to summarize feature. … I often like to move away from AI features when browsing online. But sometimes I don’t feel like reading the entire article top to bottom and just want the main points.

Firefox user on r/firefox

March 2026

Most importantly…

One small piece of the internet is usable again.

Read what we learned about designing for AI →

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