The Stack browser: what it does and where it breaks down

Someone running a browser with forty open tabs eventually hears about Stack, the macOS browser that puts web pages side by side as cards instead of stacking them into a tab strip. The screenshots look like an answer. What is harder to find is a plain account of what the product is right now: which version people are talking about, how a person actually gets in, and which of the advertised capabilities are shipped versus planned. All three of those questions have concrete answers on the vendor's own pages, and the answers matter more than the screenshots.

The short version is that Stack is a Chromium based browser built on a forked Electron, it is in closed beta rather than general release, and several of the things a daily driver browser needs are listed on the roadmap rather than in the build.

Cards instead of tabs, and what that actually changes

The core idea is spatial. Rather than a row of shrinking tab titles, Stack places open sites as cards arranged side by side in a horizontal space. Two or three cards can be visible at once, which means a chat window and a document can sit next to each other without a second application window and without splitting the screen manually.

Cards are grouped into what Stack calls Flows. A Flow is the named container: one for a client, one for study, one for shopping. The vendor's own examples on the pricing page use exactly that pattern, with names like work-work, personal, study, news, and shopping. Navigation between Flows is keyboard first, and the product pushes a mode it calls Fly Mode, reached with Command and Escape, for jumping around without reaching for the trackpad.

Separately from Flows, Stack supports multiple profiles, and the plan comparison lists unlimited profiles on every tier including the free one. This is the distinction that gets lost in most write ups. A Flow arranges what is on screen, and a profile decides which account is signed in. Two Flows inside one profile share one Gmail session. Anyone evaluating the product for the specific problem of two work accounts and one personal account needs to test the profile behavior, not the card layout, because those are separate mechanisms solving separate problems. The same split shows up in every tool in this category, and it is worth reading how a per app workspace draws that boundary before assuming a visual grouping equals an identity.

Two different products share the name

Search results for Stack mix two generations of software, and advice written for one does not apply to the other.

Stack Legacy is the term the vendor uses for the earlier version, developed and maintained from 2019 to 2021. It served as the proof that the card model was worth building, and it is the version most of the older reviews and YouTube walkthroughs describe. The current product is a separate build. According to the roadmap text on the pricing page, the application was rebuilt from the ground up in December using native technology, with better memory behavior and a structure meant to scale.

The practical consequence is that a tutorial from 2021 may describe menus, shortcuts, and extension behavior that no longer match. It also means a reader who installed Stack years ago and abandoned it was probably using Legacy, so a fresh evaluation is not a repeat of the old one. When reading any third party review, the first question is which generation it covers, and the second is its date.

Getting in is a step of its own

Stack is not a download and run product. The FAQ on the pricing page states directly that it is in a closed beta phase and not yet publicly available, and lists three routes in:

No, Stack is currently in a closed beta phase and not yet publicly available. However, early access is being granted to Stack Legacy users, people on the waitlist, and those who purchase Lifetime Licenses.

An invitation code, received through the waitlist or a community partnership, is entered on the start screen. A paid lifetime license unlocks access through the associated email or a connected wallet. Existing Legacy users can pull the new build from inside Legacy itself. Anyone who downloads the installer without one of those three things has an application that stops at the door.

Platform support is Mac and Windows. The installers published on the download page cover Intel Macs, Apple silicon Macs, and Windows. Linux is listed as unavailable, and the answer giving an estimated Linux timeline still reads Q4 2023, which is a useful signal in itself about when that page was last revised. Anyone budgeting time for an evaluation should account for the access step before the setup step, because the waitlist path does not have a stated turnaround.

The engine underneath, and what it implies for memory

Stack runs on Chromium, and the vendor is explicit that it reached Chromium through Electron rather than by building a browser shell from scratch. The FAQ describes forking Electron and adding native components, including a native scroll view so that dragging horizontally through cards feels native rather than like scrolling a web page.

Two consequences follow, and both are stated on the same page. First, memory per card is roughly memory per Chrome tab, because the engine is the same. Putting twelve services on screen as cards does not make them cheaper to run than twelve tabs. Second, the product ships a card suspension mechanism that puts a card to sleep when work on it is finished, which is the lever that keeps a large arrangement from consuming everything.

That is an honest trade and worth naming plainly. A spatial layout does not reduce resource usage on its own. It reduces the searching, and the memory question is handled separately by suspending what is not in use. Anyone who currently has forty tabs open because closing them means losing the thread will hit the same ceiling in cards unless the suspension habit comes with the move.

Where it breaks down today

Three gaps are documented by the vendor, and each one decides whether this can be a main browser or a second one.

Chrome extensions are not supported in the current build. The FAQ says so in one line, then describes extension support as the top priority with work already underway. The home page separately markets compatibility with favorite Chrome extensions as a feature, so a reader comparing the two pages is seeing an intention and a current state side by side. For anyone whose password manager, ad blocker, or clipper is non negotiable, this is the deciding fact.

Importing from another browser is also not available yet. History, bookmarks, saved sessions, and passwords have to be reached some other way during an evaluation, and the FAQ describes gradual import support as being added alongside extensions. The roadmap on the same page lists a password manager and a download manager as parts of the next milestone, which means those are planned rather than present.

The third gap is the state of the build itself. The installers linked from the download page are version 4.9.13-beta.1, and the files served from the vendor's own storage carry a last modified date of 10 October 2024. Live collaboration, the multiplayer capability the product is organized around, is labelled coming soon on both the home page and the plan comparison. The Blog entry in the site navigation points to a separate host that does not complete an HTTPS connection. None of those items is a verdict. Together they describe the tempo a person is buying into.

Question	What the vendor states
Availability	Closed beta, access by invitation code, waitlist, purchase, or upgrade from Legacy
Platforms	Mac (Intel and Apple silicon) and Windows. Linux not available
Engine	Chromium, reached through a forked Electron
Chrome extensions	Not supported in the current build, described as the top priority
Import from another browser	Not available yet, being added gradually
Live collaboration	Coming soon
Current installer	4.9.13-beta.1, files dated 10 October 2024

Who is behind it

For a product sold partly as a bet on its roadmap, the shape of the company is part of the product description.

The site footer identifies the entity as Stackers, registered in Delaware. The pricing page names Peak Capital, Lunar Ventures, 500Startups, and Wayra X among its backers, and states a total of eleven investors across ten countries. Alongside that institutional funding, the home page announces a listing on WeFunder, which is a route for users to take an equity stake rather than merely a licence.

The same page describes a limited run of lifetime licences whose revenue is directed at shipping the first version of live collaboration, and gives two stated reasons for selling them: raising upfront money that demonstrates viability, and growing a committed community. An earlier version of the same move is described in the FAQ, where supporters who bought lifetime licences during 2020 are named Stack Angels, a step the answer attributes to the financial pressure of that period.

None of that is unusual for independent software, and the transparency about it is better than average. It does establish what kind of thing is being adopted. This is a small team funding development partly from its users, running a closed beta, with the headline capability still ahead of it. A reader who is comfortable with that can evaluate the browser on its merits. A reader who needs a finished tool with a support contract is looking at the wrong stage of product.

Who the shape fits, and who it does not

The card model answers a specific complaint: too much time spent hunting for a window that is already open. For a person who works across a handful of web services all day and switches between them constantly, having three of them visible at once and the rest one keystroke away is a real change in how the day feels.

It answers a different complaint less well. Someone whose actual problem is that the same service is signed in to three accounts needs the profile layer, and needs to verify that notifications, downloads, and session state behave the way the plan implies. Someone whose problem is that macOS Command Tab lands on the browser rather than on a specific service will find that a single application window keeps that behavior no matter how the inside is arranged. That is a structural property of any tool that puts everything in one process, which is why the alternatives in this category differ mainly in how strictly each service is kept in a window of its own and how many services they are prepared to host, something a list of supported services makes concrete faster than any feature page.

The honest framing is that Stack is an ambitious product in an unfinished state, sold partly as a bet on where it is going. That is a reasonable thing to buy if the destination is appealing and the money is small. It is a poor thing to buy if the expectation is a finished replacement for the browser currently running the workday.

What to check before anything else

Install the beta only after access is secured, then test one thing: open the same service in two profiles and confirm that both stay signed in at once. If that holds and the missing extensions are survivable, keep Stack as a second browser for a fortnight and watch whether the card habit sticks. If profile separation is the actual requirement and the wait for extensions is not acceptable, compare what a browser that keeps each service in its own window does differently before committing time to any migration.