# Tor Browser

Application: The Tor Project

Also called tor, torbrowser, the onion router browser

The Tor Project, Browsers

A Firefox ESR fork from the Tor Project that routes traffic over the Tor network. On Windows the process is firefox.exe.

## What you need to know

Tor Browser is a Firefox ESR fork that uses Tor. Stock Firefox does not.

The Tor Project ships a hardened Firefox ESR that connects through Tor circuits. The process name is firefox.exe. Stock Mozilla Firefox is a different install and does not onion-route your tabs.

- **What is it?**: Firefox ESR that uses the Tor network

  **Same as Firefox?**: No. Different build and traffic path

  **Same as Mullvad Browser?**: No. Mullvad does not use Tor

Feex says

If I see firefox.exe under a Tor Browser folder, I treat it as Tor, not Mozilla Firefox. I would not "fix" it by installing stock Firefox on top.

## What is Tor Browser?

Tor Browser is the Tor Project's Firefox ESR-based browser. It starts a Tor client and sends browser traffic over Tor. The window process is firefox.exe inside the Tor Browser folder.

## If you have never used it

If you need the Tor network in a browser, this is Tor Browser, not stock Firefox. Download it from torproject.org/download. It is a Firefox ESR fork that builds circuits through Tor. Sites see a Tor exit, not your home IP. Mullvad Browser looks similar and does not use Tor. Stock Firefox from mozilla.org is a different product.

## What is it used for?

**Browse over Tor**

HTTP(S) through Tor circuits. This is the product job. Stock Firefox does not do this.

**Onion sites**

.onion addresses the Tor client can reach. A normal browser cannot open those without extra software.

**Fingerprint-resistant defaults**

Window size, letterboxing, and NoScript-style defaults the Tor Project ships. They can break some sites on purpose.

## Who is it for?

- People who were told to use Tor Browser, not "Firefox plus a VPN"
- Users who need .onion reachability
- Anyone who saw firefox.exe and assumed Mozilla Firefox

## Current status

Actively developed. Releases follow Firefox ESR plus Tor Project patches. This article is the Windows desktop bundle.

## How old is it?

The Tor Project shipped a dedicated browser bundle in 2008. Firefox itself is older. Current Tor Browser is still an ESR fork, not a Chromium reskin. A 2004 "Privoxy plus Firefox" guide is not this installer.

## Versions

Major channels first. Exact build numbers are not all verified here.

Stable

Alpha

## System requirements

Values follow the publisher's public guidance. Workload still changes the real need.

### Minimum

| CPU              | A 64-bit processor current Tor Browser lists for Windows          |
| ---------------- | ----------------------------------------------------------------- |
| RAM              | 2 GB class can start it. Circuits and content processes want more |
| Operating system | Windows 10 or Windows 11, per the Tor Project install docs        |

## Resource profile

- **CPU demand**: Circuit setup plus the page

  **RAM demand**: Firefox content processes

  **Network demand**: Tor is slower than a direct connection. That is expected

## Installed processes

These executables belong to this product when it is installed.

| firefox.exe | Tor Browser window and content processes |
| ----------- | ---------------------------------------- |
| tor.exe     | Tor client the bundle starts             |

## Startup components

Tor Browser is not meant to sit in Windows Startup. You launch it when you want a Tor session. It does not replace your default browser unless you set that.

## File locations

| Typical portable-style folder | A Tor Browser folder you chose, often under the user profile |
| ----------------------------- | ------------------------------------------------------------ |
| Do not confuse with           | C:\Program Files\Mozilla Firefox\\                           |

## File formats

HTML, PDF, PNG, JPEG

## Common problems

### Sites break or look letterboxed

Security level and fingerprint defenses shrink the canvas. That is Tor Browser, not a GPU failure.

### People update Firefox and break the bundle

Do not overwrite this firefox.exe with Mozilla's installer. Update from the Tor Project.

## Getting unstuck

### Confirm the folder is Tor Browser

firefox.exe next to a Tor Browser Start Tor Browser shortcut is this product. Program Files\Mozilla Firefox is stock Firefox.

### Use the onion button and circuit display

A new circuit is a Tor Browser control. Changing Windows proxy settings by hand is the wrong first step.

### Download only from torproject.org/download

Fake Tor installers are a long-running scam. Verify the signature the manual describes.

## Alternatives

Mullvad Browser if you want the same hardening without Tor. Stock Firefox if you want a normal Gecko browser. A VPN app is not a Tor Browser replacement.

## Official help and downloads

Start with the vendor. Random exe sites are not a support channel.

| Download       | [www.torproject.org/download/ ](https://www.torproject.org/download/)Official Windows package       |
| -------------- | --------------------------------------------------------------------------------------------------- |
| User Manual    | [tb-manual.torproject.org/ ](https://tb-manual.torproject.org/)Install, verify, and security levels |
| Support portal | [support.torproject.org/ ](https://support.torproject.org/)Circuits, bridges, and errors            |
| Project site   | [www.torproject.org/ ](https://www.torproject.org/)What the Tor Project ships                       |

## Related hardware

A modest CPU is enough. The delay is usually the Tor path, not a missing gaming GPU.

## Technical details

Technical details

ESR-based version numbers change on the Tor Project train. This article does not pin a build.

## Related

These entities connect to this article. Type is shown on every link.

[Mullvad Browser: Application](https://feex.it/wiki/software/mullvad-browser)[Mozilla Firefox: Application](https://feex.it/wiki/software/mozilla-firefox)[What is a Windows process: Guide](https://feex.it/wiki/software/system/what-is-a-windows-process)

## Sources and verification

Reviewed by Feex editorial. Last verified August 2026 Status: Feex Reviewed. [How we research](https://feex.it/wiki/research).

- [Tor Browser download ](https://www.torproject.org/download/)· Official Windows package
- [Tor Browser User Manual ](https://tb-manual.torproject.org/)· Official manual
- [Foxhole process map ](https://foxhole.feex.it/)· First-party samples on Windows PCs. Not a lab benchmark.

## Was this article useful?

A yes or no is enough. Pick a reason if you want, or add a short note.

Quick facts

The short identity of this page. Specs, sources, and the full story stay in the article.

- **Developer**: The Tor Project

  **Category**: Web browser

  **Process**: firefox.exe

  **License**: Free and open source

  **First released**: 2008

  **Official site**: [torproject.org](https://www.torproject.org/)

  **Mapped by Feex**: Seen on Windows PCs in Foxhole

Feex Reviewed: Last verified August 2026

---

Source: [Canonical Feex Wiki page](https://feex.it/wiki/software/tor-browser/)

[Developer guide](https://feex.it/wiki/developers/) | [API policy](https://feex.it/developers/api-policy/) | [Agent guidance](https://feex.it/wiki/llms.txt)