Atrium Browser
A tiled Mac browser, with an iPhone and iPad companion, that keeps many signed-in logins to one site open at once.
About
Atrium Browser is a tiled Mac browser: one window holds several signed-in logins to the same site at once, each in its own tile. Bookkeepers, social media managers, ad agencies, virtual assistants, multi-store sellers, and families managing shared travel accounts keep every login open together instead of logging out and back in all day.
A Multitab is a saved layout: pick a destination, choose how many accounts, and Atrium Browser lays them out in a clean gallery, each tile its own isolated session. Sign in once per tile and it stays signed in. Folders and auto-categories keep a dozen-plus accounts organized, and a saved layout reopens by name from Spotlight or Alfred.
Atrium Browser ships with a built-in Model Context Protocol (MCP) server, so Claude or any MCP-speaking client can read, navigate, and act inside the tiles you allow. Banking, Cards, and Investing folders are walled off from AI by default, and every action happens inside the same visible, signed-in session you set up yourself.
Folders and tiles sync to the iPhone and iPad companion app, along with your saved passwords, paired by scanning a QR code and encrypted end to end. Atrium Browser is free for up to three accounts, a one-time $29 covers up to 12, and an optional Premium membership adds hosted AI.
Per-tile login isolation
Each tile keeps its own local, signed-in session, so accounts keep cookies isolated and do not bleed into each other. Open the same site in every tile and stay signed into a different account in each one.
Multitab layouts
Save a set of isolated logins as one named layout: point it at a destination, sign in to each tile once, and reopen the whole gallery any time, or launch it straight from Spotlight.
Built-in MCP server for AI agents
A local Model Context Protocol server lets Claude or any MCP client read, navigate, and act inside the tiles you allow, while Banking, Cards, and Investing stay walled off by default.
Follow, Focus, and full controls
Follow mode drives every tile from one address bar; Focus spotlights a single tile and dims the rest. Every tile keeps its own back, forward, reload, and address bar.
Cross-device sync
Folders, tiles, and saved passwords sync to the iPhone and iPad companion app, paired by scanning a QR code on the Mac and encrypted end to end.
Light on your Mac
Only the tiles you are looking at run live. The rest freeze to a snapshot, and the whole grid suspends when the window moves to the background, so even a full gallery stays easy on the Mac.