Hey hey Connect community!
I'm here with the Firefox Search & Suggest team to get your feedback on a new feature called Semantic History Search.
Below are some details on what the feature is, why we're working on it, how to enable it, and how to provide valuable feedback right here in this thread.
Brief description
Firefox users often struggle recalling previously visited websites, especially when relying solely on Firefox’s direct-match history search.
When exact keywords are forgotten, it can be hard to find the right input to recall important sites from browsing history. Human memory is not generally based on URLs and page titles, but rather on contextual meaning.
Proposed Solution
To solve this problem, we’re testing client-side natural language querying of history in the address bar.
Once enabled, Firefox will download a small language model (Xenova/all-MiniLM) and create a vector database based on your existing history. This new resource will provide the relational context to enable Firefox history suggestions that are semantically related to your search. All matching is done on-device. No new data collection or model training is involved, and your browsing history doesn’t leave your device. The existing history data on your device is made more rich and referential. This means your private browsing history stays private, which makes it difficult for us to understand whether your experience is improving.
For example, if you’re a basketball fan, you might have visited “NBA.com”. Existing Firefox history search would not match the term “basketball” to NBA.com because the term does not appear in the page title or URL. The Semantic History search improvement would match, as “NBA” and “basketball” are closely related in semantic terms.
We’ve tested our own profiles and synthetic clients, but everyone’s history is unique. We need your feedback on how well this works for you.
Getting started
First some reminders:
- History suggestions are from YOUR history, which can contain sensitive information. Try and use a profile that has a significant (multiple months) of browsing history.
- Rest assured that as always, your browsing history will stay private as you test this feature.
- Please only submit feedback involving information you feel comfortable sharing.
Follow these steps, and ask questions in the comments below.
1. Download or update to the latest desktop version of Firefox Nightly: 141.0a1 or newer.
2. Ensure that history suggestions are enabled in settings (about:preferences#search)

- Browsing history suggestions appear in a section of address bar results labeled “Firefox Suggest”, and include the page title and URL.
3. Enable the feature:
- Type “about:config” into the Firefox address bar
- Set the value of places.semanticHistory.featureGate to true
4. Enable debugging icons:
- Still in “about:config”, create a new boolean pref named browser.urlbar.showDebuggingIcons and set its value to true
- This will add a small ‘s’ to the page’s favicon in history suggestion results to help identify the result was one determined by the new semantic matching capability:

- You may alternatively see a small ‘a’ in a page's favicon. This indicates a direct match based on the existing adaptive history logic.
- This pref is intended to help with foxfooding, and can be disabled after testing is completed.
5. The vector database will take ~10 minutes to build, and will happen in the background. Semantic history suggestions may be less relevant during this time.
Feedback
Feel free to comment below if you have any questions or need support.
- Perform searches for items in your history as you normally would:
- Observe the results that are shown in the Firefox Suggest section, looking for semantic results that have the “s” icon.
- Consider the following questions:
- Do the history suggestions help you find pages when you remember the topic but not the exact words?
- Are you finding relevant pages in your history more easily than before?
- Compared to before, how much easier is it to find pages in your browsing history?
- Are you seeing more unexpected results?
- If so in either case, for any particular kinds of searches?
- Add each of your results to the comments section of this post:
- What you typed to find it
- Were the results what you were looking for, or were they unexpected?
- Example: “I was trying to find the NBA subreddit and I typed “basketb and the result I got was…”
- What semantic history results were shown, if you’re comfortable sharing
Bugs/ General Feedback
If you find issues or would like to provide general feedback, please feel free to comment in this post as well.
A big thanks in advance for your participation 💪