If you want to understand how to check what data Firefox browser collects, the key is knowing where Mozilla stores telemetry, studies, and privacy settings.
This guide shows you how to inspect those controls, what data categories may be involved, and which options affect sharing.
Firefox is built with privacy controls, but it can still send technical and usage data unless you review the right menus.
A few minutes of checking can reveal exactly what is enabled and what you can turn off.
What Firefox Data Collection Usually Includes
Firefox may collect different types of data depending on your settings, installed features, and participation in optional programs.
Mozilla uses much of this information to improve stability, security, performance, and product decisions.
- Technical data: browser version, operating system, device type, crash reports, and performance metrics.
- Usage data: feature interactions, startup time, page load performance, and settings usage.
- Interaction data: clicks on Firefox interface elements, search usage, and add-on behavior.
- Diagnostic data: memory usage, errors, hang reports, and other troubleshooting signals.
- Studies and experiments: limited participation in feature tests or A/B experiments.
Firefox is not designed to collect the contents of your browsing in the same way as a tracking service, but telemetry can still include browser behavior details that many users prefer to control.
How to Check Firefox Telemetry Settings
The fastest way to review data collection is through Firefox’s built-in privacy controls.
These settings vary slightly by version, but the path is generally the same across modern desktop releases.
Open the Privacy and Security settings
- Open Firefox.
- Select the menu button in the top-right corner.
- Choose Settings or Preferences.
- Click Privacy & Security in the left sidebar.
Scroll until you find the Firefox Data Collection and Use section.
This area is the most important place to inspect if you want to understand what the browser may be sending to Mozilla.
Review the data collection checkboxes
In this section, Firefox may show one or more options such as:
- Allow Firefox to send technical and interaction data to Mozilla.
- Allow Firefox to install and run studies.
- Allow Firefox to send backlogged crash reports on your behalf.
Each checkbox represents a different type of sharing.
If a box is selected, that category is enabled.
If you want less data collection, uncheck the options you do not want.
How to Inspect Firefox Studies and Experiments
Mozilla sometimes uses studies to test new features or UI changes on a limited group of users.
If you are checking how to check what data Firefox browser collects, you should also verify whether studies are enabled.
Look for the studies setting
In Privacy & Security, find the option related to studies or experiments.
If enabled, Firefox can download and run limited experiments that may gather device and usage information relevant to the test.
Users who value tighter privacy often disable studies unless they specifically want to help test Firefox features.
Turning this off usually reduces the browser’s participation in product experiments.
Check remote settings and feature rollouts
Firefox may also receive configuration updates and feature rollouts through Mozilla infrastructure.
These are not always traditional telemetry, but they can still influence which features appear and how the browser behaves.
You do not usually need a separate menu for this, but it helps to know that data-related behavior can come from both explicit privacy settings and background product systems.
Use About:Telemetry for a Deeper Look
Firefox includes diagnostic pages that expose what the browser is reporting.
The most useful one for advanced users is about:telemetry.
Open the telemetry page
- Type about:telemetry into the address bar.
- Press Enter.
- Review the dashboard sections that appear.
This page can show categories such as environment data, subsystems, events, hang reports, and performance information.
It is not always simple to read, but it gives a clearer view of the kinds of metrics Firefox can record.
What to look for on the page
- Session information: browser session counts and startup details.
- Environment data: general hardware, OS, and Firefox configuration details.
- Scalars and events: aggregated counts tied to browser actions.
- Histograms: performance measurements such as timing and frequency.
If you are trying to audit what the browser records locally before anything is transmitted, this page is one of the clearest tools available inside Firefox.
Check Crash Reporting Controls
Crash reports can contain valuable diagnostic details, but they are also part of Firefox data collection.
If you want to check what data Firefox browser collects, review the crash reporting option separately from general telemetry.
Look for settings that allow Firefox to send crash reports automatically.
When enabled, Firefox may transmit technical information about failures, stack traces, and memory conditions that help Mozilla identify bugs.
Disabling crash reporting will reduce the amount of diagnostic data sent when the browser or tabs fail unexpectedly.
Review Firefox Account and Sync Settings
Firefox Sync is a separate feature from telemetry, but it affects what data is stored and synchronized across devices.
If you use a Firefox Account, review what is being synced.
Common sync categories include:
- Bookmarks
- History
- Open tabs
- Passwords
- Add-ons
- Settings
Sync is end-to-end encrypted for certain data types, but it still involves cloud storage and cross-device transfer.
If your goal is minimum data sharing, check which sync items are enabled in your Firefox Account settings.
How to Reduce Firefox Data Collection
Once you know what is enabled, you can limit collection without breaking core browser functions.
These are the main controls most users should review.
- Disable technical and interaction data sharing.
- Turn off studies and experiments.
- Disable automatic crash report submission.
- Review and limit Firefox Sync categories.
- Consider using strict tracking protection settings.
- Clear cookies and site data on a schedule if you want less persistent browsing data.
Some users also install privacy-focused add-ons, but add-ons should be chosen carefully because they themselves can access browsing data.
Prefer reputable extensions from the Mozilla Add-ons ecosystem.
Where to Find Mozilla’s Data Practices Documentation
Firefox settings show what is enabled on your device, but Mozilla’s documentation explains how the company handles collected data.
For a full audit, read the privacy policy and telemetry documentation on Mozilla’s official site.
Look for references to:
- Telemetry and data collection categories
- Optional studies
- Crash reporting
- Data retention and aggregation
- How Mozilla uses and shares technical information
This documentation is useful because it clarifies the difference between browser telemetry, synced account data, and browsing content stored locally on your device.
Mobile Firefox Data Collection Checks
Firefox on iPhone and Android has privacy controls too, but the menus differ from desktop.
If you use Firefox mobile, check the app settings for privacy, data sharing, and default browser permissions.
On mobile, you should review:
- Data sharing or usage analytics options
- Tracking protection settings
- Default browser and permissions
- Account sync behavior
- Notification and storage permissions
Because mobile operating systems also collect their own diagnostics, it helps to separate Firefox’s settings from the device-level privacy controls in iOS or Android.
Quick Checklist for Auditing Firefox Data Collection
If you want a simple audit process, use this checklist:
- Open Privacy & Security.
- Find Firefox Data Collection and Use.
- Review technical data sharing.
- Disable studies if you do not want experiments.
- Check crash reporting options.
- Open about:telemetry for deeper visibility.
- Review Firefox Account sync categories.
- Read Mozilla’s privacy and telemetry documentation.
These steps give you a practical view of how to check what data Firefox browser collects and how to decide which parts of that collection you are comfortable allowing.