What actually keeps two accounts apart

The problem

What leaks between two tabs

A browser profile is a directory on disk, and everything a site can write goes in it: cookies, localStorage, IndexedDB, the HTTP cache, service-worker registrations, permission grants. Two tabs in the same window share all of it. So does a second window. A site does not have to do anything clever to connect them — it simply reads the identifier it stored the first time.

The usual workarounds each close one channel and leave others open. An incognito window gets a fresh jar, but every incognito window shares one jar with the others, and closing them all throws away the session you wanted to keep. Container extensions partition cookies and storage while running inside the same browser process, on the same installed extensions and the same hardware fingerprint. A second browser gets you a second identity, and then a third account needs a third browser.

Profiles

A directory per profile

In Argus the unit of separation is the profile, and the profile is backed by its own user-data directory. Not a partition inside a shared one — a separate tree that Chromium is pointed at when the session starts. Each session starts from its own directory with nothing carried over from any other.

• ✓A dedicated user-data directory per profile — separate storage, cache, and cookie jar

Because the boundary is a directory rather than a setting, it scales the way the file system does. Hundreds of fully isolated profiles, each with its own storage, cookies and identity. The list is built for that scale rather than for a handful of tabs — folders, tags, search and filters, bulk launch and bulk edit, and a soft delete that sends a profile to Trash instead of destroying a session you may still want.

The browser

Nothing carries over from the last run

A separate directory is not enough on its own, because a browser tries hard to be helpful about the last time you used it. Restored tabs, a recovered session, a form the crash handler kept — each is a way for a previous run to reappear inside a new one, and for an account you closed on Tuesday to be open beside a different account on Wednesday.

• ✓Session restore is disabled, so a previous run cannot resurface in a new one

The browser

The proxy is applied at the network layer

Isolating storage while every profile shares one exit IP solves half a problem. In Argus the proxy belongs to the profile and is applied to the session itself, not through a proxy-switching extension of the kind a page can enumerate and read.

• ✓The proxy is applied at the network layer, not through an extension that a page can detect

What the address has to survive once it is applied — health checks, the sites that refuse it, and what happens when a check fails — is the subject of how proxies work in Argus.

The browser

The ports a site probes to spot automation

There is a detection technique that has nothing to do with storage: a page asks the browser to connect back to localhost on the ports that automation frameworks and remote-desktop tools listen on. An ordinary visitor's machine refuses; a machine running a debugging port answers, and the page has learned something no fingerprint would have told it.

• ✓A default block list covers remote-access ports that sites probe to detect automation

Cookie sets

Signing in once, without passing the password around

Isolation raises an obvious practical question: if every profile starts empty, does somebody have to sign in to each one? No — the session is a thing you can store and assign. Upload a cookie set once, then assign it to any profile that needs it.

• ✓A shared library — swap a set between profiles without re-uploading it
• ✓Import from a file or a whole folder at once
• ✓Cookies are seeded into the session at launch, so the profile opens already signed in

For a team this is the difference between a shared password in a group chat and a login that lives with the profile. Whoever opens it lands already signed in, and nobody needs the credentials to do the work. The agency setup is built on exactly this.

Honestly

What isolation cannot fix

Isolation guarantees two profiles share no state. It does not make them look like two different people, and on its own it will not keep accounts apart.

Two perfectly isolated profiles running on one machine still draw the same canvas, report the same GPU and keep the same clock — how fingerprinting works covers the device half. And they still leave from the same IP unless each one is given its own proxy. All three have to hold at once; any one of them alone is a setup that works right up until it does not.