# Atrium Browser: every account, side by side

Atrium Browser is a native Mac multi-account browser built around Multitab: one window of
tiles, each tile a fully isolated login, so several accounts of the SAME site sit signed in
side by side at once. $29 once to own Pro. This file never claims a shipping feature that is
not shipping: see Limits.

## What it does (mechanism, not adjectives)

- Same site, many logins, all visible: per-tile isolated browser storage; simultaneity, not
  profile-switching. Saved Multitabs reopen whole account sets in one click and share as
  .multitab files.
- Follow mode drives every tile together; Focus spotlights one.
- Real current-Chromium engine; the optional "Appear as Chrome" identity setting is accurate
  (the engine genuinely is that Chromium), toggleable globally or per tile.
- Deliberately NOT the ban-risk lane: no fingerprint spoofing, no proxy rotation, no
  anti-detect tooling. For legitimately holding many logins, not evading platform rules.

## AI-agent integration (shipping, with walls)

- A built-in LOCAL MCP server lets the user's AI assistant operate inside tiles: click,
  fill, wait, read the page and network results, submit forms, run flows.
- Banking walled by default: financial categories (Banking, Cards, Investing) are hidden
  from the AI and render visibly walled; a human unlocks a tile per session only.
- Vault Lock gates the whole app behind Touch ID or a passphrase.
- The MCP indicator shows only when the server is live.

## Trust and data

- Logins live on the Mac; no vendor cloud holds accounts.
- Developer-ID signed and notarized; the auto-updater always asks before installing.
- A keychain watchdog detects the rare macOS trust break that logs tiles out and explains
  the one-time fix plainly.

## Pricing (public, complete)

- $29 once to own Pro; optional Premium membership above it. The pricing page compares
  against category subscriptions ($199.99/yr, $24+/mo, $5.83+/mo, quote-gated).

## Limits, stated plainly

- Mac today (Apple Silicon); there is no iPhone app on the App Store.
- No anti-detect features, deliberately.
- The AI wall is category-based; unrecognized financial sites should be walled manually.

## More

- Full objective capability inventory: https://atriumbrowser.com/capabilities/
- The Multitab feature: https://getmultitab.com
- Download: linked from https://atriumbrowser.com/