Tor Browser and Onion URL Testing

Browserling offers free online cross-browser testing of onion websites in the Tor browser. We have installed the Tor browser on our cloud servers and we stream this browser to you. You don't need to install it yourself and you don't need any additional software as Browserling is simply powered by JavaScript and HTML5. The Tor browser is configured to automatically connect to the Tor network (also known as the onion network) as soon as you load it, and you can instantly open regular and onion links in it.

We have installed the ten latest Tor browser versions from 7.5 to 13 (currently the latest version). As soon as a new version gets released, we'll get it installed on our cloud browser platform as well.

Try Tor browser in Browserling now!

To try the online Tor browser, enter a regular URL or an onion link in the field below, and press the Test Now button:

The demo version offers three minutes of free Tor testing but to unlock unlimited testing sessions, you'll have to get the developer plan.

Tor Browser Testing FAQ

What is the Tor browser?

The Tor browser is a web browser that was created to provide enhanced privacy and anonymity for users when browsing the Internet. The abbreviation "TOR" stands for "The Onion Router" and it refers to the underlying technology and network that the browser uses to achieve these goals. It routes web traffic through a network of relay servers, making it difficult for anyone to trace a user's online activities back to their location or identity.

Which browser is the Tor browser based on?

The Tor browser is based on the Firefox browser. However, it has been modified and enhanced to provide additional privacy and security features to help protect users' anonymity while they browse the Internet.

What are the differences between Firefox and Tor browser?

Some of the key differences between Firefox and Tor browser are the following:

  • No Browser History. The Tor browser does not keep any browsing history or store details about the user's activities.
  • Disk Avoidance. By default, the Tor browser doesn't write web-related data (such as cookies and local storage) to the disk. This minimizes traces left on the device after a browsing session.
  • Isolated Cookies. The Tor browser ensures that cookies from different websites are isolated from each other, preventing cross-site tracking.
  • HTTPS Everywhere. The Tor browser has the HTTPS Everywhere browser extension included and enabled by default to ensure connections to websites are secure via HTTPS whenever possible.
  • NoScript and uBlock Origin. The Tor browser includes the NoScript and uBlock Origin extensions to block scripts and ads, which can be potential vectors for tracking or exploiting browser vulnerabilities.
  • Fingerprinting Protection. The Tor browser has protections against browser fingerprinting, which is a technique websites use to identify and track users based on their device and browser configurations.
  • Disabled WebRTC. WebRTC is disabled to prevent potential IP address leaks.
  • Fixed Window Size. To combat browser fingerprinting based on screen resolution, the Tor browser window defaults to a fixed size.
  • Uniform User Agent. The browser presents a uniform user agent to websites, making it harder to fingerprint based on browser or OS version.
  • No Auto-fill. The browser does not use auto-fill for addresses or passwords to minimize personal data leakage risks.

What is the Tor browser's user agent?

The Tor browser uses a basic user agent string to make its users look as similar as possible. This obfuscation technique helps to prevent user fingerprinting based on user agent variations. The exact user agent string varies depending on the Tor browser version and the platform. As we have installed all the latest Tor browser versions in Windows 10, we quickly went through them and here are the user agent strings for the last ten Tor browser versions:

  • Tor browser 13: Mozilla/5.0 (Windows NT 10.0; rv:109.0) Gecko/20100101 Firefox/115.0
  • Tor browser 12.5: Mozilla/5.0 (Windows NT 10.0; rv:102.0) Gecko/20100101 Firefox/102.0
  • Tor browser 12: Mozilla/5.0 (Windows NT 10.0; rv:102.0) Gecko/20100101 Firefox/102.0
  • Tor browser 11.5: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Firefox/91.0
  • Tor browser 11: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Firefox/91.0
  • Tor browser 10.5: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Firefox/78.0
  • Tor browser 10: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Firefox/78.0
  • Tor browser 9.5: Mozilla/5.0 (Windows NT 10.0; rv:68.0) Gecko/20100101 Firefox/68.0
  • Tor browser 9: Mozilla/5.0 (Windows NT 10.0; rv:68.0) Gecko/20100101 Firefox/68.0
  • Tor browser 8.5: Mozilla/5.0 (Windows NT 6.1; rv:60.0) Gecko/20100101 Firefox/60.0
  • Tor browser 8: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0
  • Tor browser 7.5: Mozilla/5.0 (Windows NT 6.1; rv:52.0) Gecko/20100101 Firefox/52.0

To find the user agent of another Tor browser version or another browser, you can also use our What's My User Agent? online tool.

What are the Tor browser's safety levels?

The Tor browser offers three safety levels. The first one is the default (standard) level and at this level all browser features are enabled. The second level is safer and JavaScript is disabled on non-HTTPs sites and audio and video elements don't auto-play. The third level is the safest and JavaScript is off on all sites and fonts are disabled.

What's the difference between the Tor browser and the Tor network?

The Tor browser is the application that allows individuals to access the Tor network for anonymous web browsing, while the Tor network (also known as the onion network) is the infrastructure that powers this anonymity and can be used for various types of Internet traffic beyond web browsing.

What is the Onion network?

The onion network is just another name for the Tor network. The name onion is used because of the way data is encrypted in layers, much like the layers of an onion. When data is sent over the Tor network, it is encrypted in multiple layers. As the data passes through each relay (node) in the Tor network, one layer of encryption is removed, revealing the next destination for the data but not the final endpoint. The Tor network consists of thousands of volunteer-run relays around the world. Data sent over the network typically passes through several randomly selected relays before reaching its final destination. By routing traffic through multiple relays and layers of encryption, the Tor network protects users from traffic analysis, a form of surveillance that can reveal who is communicating with whom over a network.

What types of network nodes make the Onion network?

There are three primary types of nodes in the Tor network. The data enters the network through an entry node, passes through one or more middle nodes, and finally leaves the network through an exit node. Only the exit node sees the final destination of the data, but it does not know the original source.

How many Tor exit nodes are there?

As of today, there are roughly 2,250 Tor exit nodes at any given time, although this is a rough estimate and the actual number can fluctuate. You can check the Tor Metrics page by Tor Project for the latest information.

How to find the IP address of a Tor exit node?

You can use our What's My IP Address? tool. If you're using a Tor browser, then this tool will show you the IP address of the last node (which is the exit node).

What are the differences between version 2 and version 3 of Onion protocol?

Here are some of the key differences between v2 and v3 of onion protocol:

  • Address Length: The v2 onion addresses were shorter, consisting of 16 characters followed by ".onion", for example, abcdefghij234567.onion. The v3 onion addresses are much longer, consisting of 56 characters followed by ".onion". This change enhances security and reduces the risk of certain types of attacks.
  • Cryptography: The v2 onion protocol used SHA1 and RSA1024 for its cryptographic operations. The v3 implements ed25519 for signature generation and verification and SHA3 for various cryptographic primitives, providing a stronger cryptographic foundation.
  • Protocol Enhancements: The v3 onion protocol introduces improved directory protocol designs and better onion address security against enumeration attacks. It also has better protection against guard node discovery and Sybil attacks.
  • Resistance to Attacks: The v3 onion protocol enhances resistance against various attacks, such as guard discovery attack.
  • Offline Keys: The v3 onion protocol supports and recommends the use of offline keys, ensuring that the main key can be kept offline to reduce risks.
  • Protocol Cleanup: The v3 onion protocol addresses several technical debts from v2, resulting in a more streamlined and efficient protocol.

Due to its various limitations and vulnerabilities, the Tor Project announced the phasing out of v2 onion services in 2020 and encouraged users and service operators to transition to v3 for improved security and privacy. In October 2021, v2 of the protocol was disabled.

What characters are allowed in an onion URL?

Tor .onion addresses use a specific subset of characters to encode their values. These addresses are generated through a hash of a public key and then encoded using base32. The base32 encoding scheme uses a 32-character set that consists of the English alphabet letters a-z and numbers 2-7, all in lowercase. So all the valid characters in an .onion URL are: abcdefghijklmnopqrstuvwxyz234567. Note that this does not include the entire alphanumeric set. It omits the numbers 0 and 1 and the uppercase characters. This is designed to minimize potential confusion between similar-looking characters, like "O" (letter oh) and "0" (digit zero) or "l" (letter el) and "1" (digit one).

What's the maximum length of an onion URL?

The length of a standard .onion address now is 56 characters, followed by the ".onion" suffix. It used to be 16 characters for v2 of the onion protocol but these shorter URLs have now been disabled in favor of the more secure and modern v3 URLs.

What is a hidden service?

A hidden service is a feature of the Tor network that allows users to offer various services, such as websites or messaging servers, without revealing their IP address and ensuring the privacy and anonymity of both the service operator and the users accessing that service. These services can only be accessed through the Tor network and have unique .onion domain names.

What is the deep web, dark web, and dark net?

The term "deep web" refers to the portion of the Internet that is not indexed by traditional search engines, such as Google or Bing. This includes password-protected websites, private databases, academic journals, forums and message boards, among other things. Unlike the "open web", which is readily accessible and searchable, the deep web requires specific credentials or authorization for access. Despite its mysterious-sounding name, the deep web comprises a vast majority of the Internet's content.

The "dark web" is a subset of the deep web that is intentionally hidden and requires specialized software like Tor to access. It is often associated with anonymity and privacy, allowing users to browse and communicate without revealing their identity. While it serves various purposes, including whistle-blowing and secure communication, the dark web is also known for hosting questionable content. Accessing the dark web itself is not illegal, but many activities conducted there may go against the law, so exercise caution and ensure you're adhering to the laws and regulations of your country.

The terms "dark web" and "dark net" are often used interchangeably, but they have slightly different meanings. The dark web refers specifically to the content hosted on dark net networks. The darknet is more about the underlying infrastructure. It refers to the actual network of private servers and routing protocols (such as the onion protocol) that make anonymous, unindexed services possible.

Why are the terms deep web, dark web, and dark net often confused?

The terms "deep web", "dark web", and "dark net" are often confused due to a lack of public understanding and media sensationalism that blurs their distinctions. All three relate to parts of the Internet that are not indexed by standard search engines, contributing to the perception that they are similar or interchangeable. Additionally, popular culture and media frequently focus on the more illicit aspects of these areas, reinforcing misunderstandings and creating an aura of mystery around all three terms. The overlap between these terms, such as the fact that the dark web is a part of the deep web and runs on dark net infrastructure, also adds to the confusion.

Why would someone create a dark web version of their website?

Creating a dark web version of a website can offer enhanced privacy and security for both users and site operators, ensuring the site content remains accessible despite censorship, surveillance, and other aspects. Here are some motivations behind organizations or individuals choosing to create dark web versions of their sites:

  • Censorship Resistance: In countries with strict Internet censorship, the dark web can provide a way for citizens to access information without governmental interference. Sites on the Tor network are much harder for authorities to block.
  • Privacy and Anonymity: The Tor network allows users to access content without revealing their IP address or other personal information, protecting them from surveillance and potential backlash, especially in countries where freedom of expression is curtailed.
  • Journalistic Integrity and Whistle-blowing: For entities like BBC, CNN, and The Washington Post, having a presence on the Tor network can provide a more secure platform for whistle-blowers to share information, ensuring secure communications between journalists and sources.
  • Broadened Reach: By being available on the Tor network, the organizations can ensure that they reach a wider audience, including those who for various reasons predominantly use the dark web for their browsing.
  • Demonstrating Commitment to Internet Freedom: By establishing a presence on the dark web, the entities can make a statement about the importance of Internet freedom, the open exchange of information, and the right to privacy.

What are the most popular hidden services?

Many renowned companies and institutions, including Facebook, Reddit, Twitter, BBC, CNN, and The Washington Post are offering the dark web versions of their websites and services. This move is largely motivated by a desire to ensure accessibility, especially in regions facing strict Internet censorship. Moreover, providing a presence on the dark web underscores their commitment to user privacy and freedom of information, while also catering to a growing audience that prioritizes online anonymity.

You may access them via these onion links:

What is a .onion domain?

A .onion domain refers to a special-use domain suffix that designates an anonymous, hidden service reachable through the Tor network. These domains are not accessible through traditional browsers or outside the Tor network. Onion domains are designed to ensure the privacy and anonymity of both the service provider and the users accessing the service. The physical location (IP address) of the server hosting the hidden service and the IP addresses of the users are obscured. The .onion address itself is generated using cryptographic methods. It's derived from the service's public key, ensuring that only the entity with the corresponding private key can operate that specific onion service.

How to open an .onion link online?

You can either install Tor browser yourself or use our online service. Enter the onion link address in the widget below and press the open button. It will instantly load a cloud version of the Tor browser and you can start browsing.

How to visit an Onion website without the Tor browser?

You can visit an onion website or an .onion link by simply going to our home page and selecting the Tor browser. We have preinstalled the Tor browser on our servers and you can instantly get access to an online Tor browser.

How to open an Onion website in Chrome or Firefox?

You can't open an .onion link directly in Chrome or Firefox as these browsers don't support the Tor network. However, you can use Browserling and get a cloud version of the Tor browser that works via Chrome or Firefox.

What to do if an Onion link doesn't open?

If you're getting a page not found error or connection issue, please first make sure you're using a Tor browser and not Chrome, Firefox, Opera, Safari, Edge, or any other browser. Only the Tor browser can open onion websites.

How to check if .onion site is up?

The simplest way to check if an .onion site is up is by opening a Browserling session (via and then navigating to the .onion site. If the Tor browser is unable to connect, then it's offline.

What does the error "Onionsite Not Found" mean?

If the Tor browser shows the error "Onionsite Not Found" (error code 0xF0), then the most likely cause is that the onion site is offline. There's little you can do in this case and you have to wait until the site comes back (try refreshing every now and then via F5).

What does the error "Onionsite Cannot Be Reached" mean?

If the Tor browser shows the error "Onionsite Cannot Be Reached" (error code 0xF1), then an internal Tor network error has occurred and you'll have to wait until Tor network starts working again (try refreshing every now and then via F5).

What does the error "Onionsite Has Disconnected" mean?

If the Tor browser shows the error "Onionsite Has Disconnected" (error code 0xF2), then the Tor network software was stopped by the onion site administrator and the web server is not reachable. In this case, you'll have to wait until the site administrator fixes the problem and restarts Tor service.

What does the error "Unable to Connect to Onionsite" mean?

If the Tor browser shows the error "Unable to Connect to Onionsite" (error code 0xF3), then the Tor network is overloaded or the onion site is too busy. You can try refreshing the site via F5 as it may be back any moment.

What does the error "Onionsite Requires Authentication" mean?

If the Tor browser shows the error "Onionsite Requires Authentication" (error code 0xF4), then the onion site requires a cryptographic key but none was provided. You have to ask the onion site administrator to announce the key of the Tor service on the Tor network.

What does the error "Onionsite Authentication Failed" mean?

If the Tor browser shows the error "Onionsite Authentication Failed" (error code 0xF5), then either the Tor service has been misconfigured by the onion site administrator or the Tor network has revoked the onion site's key. You should ask the onion site administrator to resolve this issue.

What does the error "Invalid Onionsite Address" mean?

If the Tor browser shows the error "Invalid Onionsite Address" (error code 0xF6), then you have entered an invalid onion site address. A valid onion website address is exactly 56 symbols long, contains only the letters a to z and digits 2 to 7, and ends with suffix .onion.

What does the error "Onionsite Circuit Creation Timed Out" mean?

If the Tor browser shows the error "Onionsite Circuit Creation Timed Out" (error code 0xF7), then the Tor network connection failed, possibly due to a poor network connection. Try to reconnect to the Tor network or restart the Tor browser.

Do you have a more convenient way to instantly load a Tor browser?

Yes, we do! We created this short URL and it will instantly load a Tor browser and preconnect to the Tor network. You can start browing the Onion links in seconds.

Is my IP address visible when using a Tor browser?

No. When you use the Tor browser, your IP address is not directly visible to the websites or services you access. The Tor network routes your Internet traffic through a series of at least three randomly selected nodes (an entry node, a relay node, and an exit node) before reaching its destination. Each step is encrypted in such a way that no single node knows both the originating and final destination of the data.

Can my IP address be detected via JavaScript when using a Tor browser?

No. The Tor browser is specifically designed to minimize the risks of IP address leakage, and this includes defenses against JavaScript-based techniques that might attempt to reveal your IP address.

What's the difference between an .onion domain and a .com domain?

Onion and com domains serve as top level domain identifiers for websites but they operate in very different environments and have distinct characteristics. Here's a comparison:

  • Accessibility. Onion domains can only be accessed through the Tor network, typically using the Tor browser or other Tor-enabled tools. Com domains are accessible from any standard web browser through the regular Internet.
  • Anonymity & Privacy. Onion domains are designed to ensure anonymity for both the website operator and its visitors. The physical location and IP of the server hosting the hidden service are obscured. In com domains, the server's IP address is publicly visible and website operators and visitors can be tracked unless additional privacy measures are used.
  • Domain Generation & Ownership. Onion domains are derived from the service's public key through cryptographic methods and there's no central registry for .onion domains. Com domains are managed by domain registrars and overseen by the Internet Corporation for Assigned Names and Numbers (ICANN). They require registration and annual fees.
  • Encryption. Onion domains provide end-to-end encryption by default. The traffic between the user and the .onion service is encrypted, ensuring intermediaries can't decipher the content. For com domains, encryption (HTTPS) is optional but highly recommended. If a com website doesn't use a HTTPS certificate, then data is transmitted in clear text.
  • Certificate Authorities (CA). Onion domains don't have a specific CA as the Onion traffic is already encrypted but some .onion sites use SSL/TLS certificates from regular CAs for added trust. For com websites, SSL/TLS certificates are often issued by recognized CAs to enable HTTPS and confirm the website's authenticity.
  • DNS System. Onion domains don't rely on the traditional Domain Name System (DNS). The Tor network handles the resolution of .onion addresses. Com domains use the standard DNS system for domain resolution.
  • Duration & Renewal. Once a .onion domain has been generated, it remains valid as long as the owner has the corresponding private key and keeps the service running. Com domains are typically registered for a certain period (usually one year) and need to be renewed periodically.
  • Legal Considerations. Operating a com domain adheres to international and national laws, with legal recourse for misuse. Onion domains are lawless and are often associated with a higher risk of activities, given the anonymity they offer.
  • Search Engine Indexing. Com domains are indexed by standard search engines like Google, Bing, and Yahoo. Onion sites are not indexed by these search engines and require specific Onion web search engines or direct URLs to access.
  • Website Hosting. Hosting a com website is straightforward and can be done through numerous hosting services. Hosting an onion site requires specific configuration to maintain anonymity and need specialized hosting services.

How to get my own .onion link?

Getting your own .onion link is quite complicated and technical process but it can be summarized as following. First, download and install Tor, then configure it (via torrc file) as a hidden service, then generate a private key, which will automatically generate a random .onion address.

How to generate a vanity .onion link?

Generating a custom .onion link is also complicated and technical process that involves a lot of computational work. You essentially need to repeatedly generate cryptographic key pairs until you get a public key that, when hashed and encoded, starts with your desired string of characters.

How often is the Tor browser updated?

The Tor browser is updated roughly every 2-3 months with minor updates and roughly once a year with a major update. The minor updates include security updates, feature updates, underlying Firefox ESR updates, and misc maintenance updates.

When was the first Tor browser version released?

Tor browser v1 was released on January 30, 2008 and it was based on Firefox

When were other Tor browser versions released?

Here's a list of major Tor browser releases beyond version 1 (which was released in January 2008):

  • Tor browser v2 was released in 2009 and it was based on Firefox 3.0.4.
  • Tor browser v3.5 was released in December 2013 and it was based on Firefox 24 ESR.
  • Tor browser v4 was released in October 2014 and it was based on Firefox 31 ESR.
  • Tor browser v5 was released in August 2015 and it was based on Firefox 38 ESR.
  • Tor browser v6 was released in June 2016 and it was based on Firefox 45 ESR.
  • Tor browser v7 was released in June 2017 and it was based on Firefox 52 ESR.
  • Tor browser v8 was released in September 2018 and it was based on Firefox 60 ESR.
  • Tor browser v9 was released in October 2019 and it was based on on Firefox 68 ESR.
  • Tor browser v10 was released in September 2020 and it was based on Firefox 78 ESR.
  • Tor browser v11 was released in November 2021 and it was based on Firefox 91 ESR.
  • Tor browser v12 was released in December 2022 and it was based on Firefox 102 ESR.
  • Tor browser v13 was released in October 2023 and it was based on Firefox 115 ESR.

How many Tor browser users are there?

It's difficult to provide an exact number of Tor users due to the anonymized nature of the network. Estimates based on metrics provided by the Tor Project suggest that the number of directly connecting users can range 2 to 3 million per day. However, these numbers are rough estimates and fluctuate over time due to various factors like global events, increased awareness about online privacy, or changes in censorship policies in different countries.

Can you help us debug a Tor problem?

We'd love to help! We have all working Tor browser versions available (from 7 to 12) and have been following the development of the Tor browser for over 10 years. We're well-versed in every aspect of this browser. You can email us at and we'll help you with your Tor browser problem.

Can I embed a Tor browser in my application?

Yes, you can! We created a technology called Live API that lets you embed any browser in any application. For example, you can embed a live Tor browser in your web page or use Tor browser from Chrome.

Do you support headless Tor browser?

Not yet, but we're working on it. Coming soon, you'll be able to use our Headless API that will let you run headless Tor browser versions and test onion websites without seeing them.


For any additional questions about cross-browser testing in the Tor browser please contact us at or use our contact form.