What is a .onion address?
A .onion address is the hostname of a service that is exposed only through the Tor network. Normal sites live at IP addresses listed in public DNS; if you know where a server is, you can attack it, block it, or subpoena its host. An onion service hides its location behind a rendezvous point. The address itself is a random string derived from the service's public key, which is why onion addresses look like a line of generated spam. The site operator gets a domain nobody can seize by asking the registry, because there is no registry.
How Tor actually routes your traffic
When you open a site through Tor, your browser builds a circuit through three relays selected from the public Tor network: a guard (entry) node, a middle node, and an exit node. Each hop decrypts one layer of the bundle, like peeling an onion. The three relays are operated by different people in different places, and each relay only knows its immediate neighbors in the chain.
- Guard node: knows your IP address, but has no idea what site you are visiting.
- Middle node: knows neither your IP nor the destination.
- Exit node: knows the destination and connects to it, but has no idea who you are.
This is how Tor solves the trust problem: you only need to trust that the three operators are not all the same person working together. Because they are dispersed and anonymous volunteers, collusion is hard. The name "onion" comes from this encryption layering, and it is also why every CleanRoom session runs Tor Browser by default: the network path is handled inside the session, on our side, not on your machine.
Why do sites use .onion addresses?
For services whose users need them, the reasons are concrete:
- Location hiding — nobody can find the server to knock it offline. This is why whistleblowing outlets and some news organizations operate onion mirrors.
- Anti-censorship — a domain cannot be taken down by a registrar, and a DNS filter cannot block a hostname it cannot see.
- End-to-end authenticated connection — the same cryptography that generates the address also authenticates traffic, so you can confirm the site is really the one its address claims to be, with no CA to compromise.
- For the operator, less liability — a site that serves sensitive content (survivor forums, leak platforms, advice for at-risk people) can exist without exposing who runs it.
Does Tor make you anonymous?
It raises the cost of linking you to your traffic enormously, but it is not a magic hood. Three honest limits:
- The exit node can see your plaintext to the final site. Tor encrypts between you and the exit node; if the site itself is plain HTTP, the exit node reads it. Always prefer HTTPS.
- Fingerprinting outlives the circuit. A browser that reports a unique screen size, timezone, or font set advertises who it is regardless of IP. Tor Browser works hard to make every user look identical for exactly this reason.
- Some sites simply refuse to serve Tor exit nodes. For those, no amount of routing helps — which is something you should hear from a tool before you pay for it. CleanRoom will not claim to force its way past a site that bans Tor.
How to open .onion sites
You need a client that speaks the Tor protocol. The standard way is Tor Browser: a hardened Firefox build that routes everything through Tor and spoofs your fingerprint to match the crowd. Install it, let it connect, and paste the .onion address into the address bar. Most onion sites load slowly the first time because they are personal machines on home connections, not CDN-fronted services.
The alternative is a service that runs Tor for you, which is how CleanRoom works. The Tor Browser profile is started inside the disposable session and streamed to your tab, so you can open a .onion address from any computer — including a locked-down work machine where you cannot install software. You never carry Tor on your device at all, and the profile dies with the session.
What the session limits mean for Tor
Tor is great at privacy and mediocre at speed. Relay selection, the extra hops, and onion routing add real latency, and sites behind Tor are sometimes run on modest hardware. We cap sessions at 60 minutes partly because of that latency: long Tor sessions on a busy circuit drift into unusable territory, and a 10–30 minute session keeps you on fresh circuits with a responsive browser. If you need to hold a Tor connection open for hours, run Tor Browser on a machine you control.
The honest bottom line
Tor is a privacy network, not a dark-web badge. It is built and funded by the Tor Project, a nonprofit, and its security properties are published, debated, and audited in the open. Use it to protect ordinary traffic: research you do not want attached to your name, reading you do not want your ISP to log, sites that treat their users'IPs as inventory. Everything disreputable that ever rode on Tor — marketplaces, abuse, scams — depends on the same infrastructure that protects a journalist interviewing a source in a risky country, and anti-abuse work happens inside the network too. Judge it the way you judge a hammer.
Related guides
- What is a disposable browser? — the full comparison with incognito mode, VPNs, and VMs
- Paying for services anonymously with Monero
- CleanRoom FAQ — including what happens to session data on close
Want to open a .onion site without installing anything? Launch a session (10 minutes, 75 cents, Monero).