What Is a Suspended Tab (and How It Frees Memory)

## Why it matters

Suspending a tab is the most direct way to reclaim memory without losing the tab itself. You've got twelve tabs open and your browser is sluggish. Close them and they're gone. You'd have to find them again or restore from history. Suspend them, and they're still there in your tab strip, but they're using almost no memory. Click one and it reloads and becomes active again instantly (or near-instantly, depending on your network).

This is what tab suspension does: it frees the resources a page was hogging whilst keeping the tab visible and clickable. That's the whole premise.

## How it works

When you suspend a tab, Scalpel calls Chrome's native chrome.tabs.discard() API. Here's what that does on the inside.

A normal, active tab has two things running: a renderer process (the part that paints pixels, runs JavaScript, holds the DOM) and a memory footprint (often 30–150 MB per tab, sometimes much more for heavy web apps). When discard() is called, Chrome tears down that renderer process. The memory gets freed. The tab still exists in your tab strip, but it's now in a discarded state. Its URL, title, favicon, and scroll position are preserved (Chrome keeps those in a lightweight state). When you click the tab, Chrome rebuilds the renderer process and loads the page from the network (or from the browser cache if it hasn't expired). From the user's perspective, the tab flashes briefly and reloads.

That reload is the trade-off: because the page reloads, any form input you typed but didn't submit will be lost. Scalpel protects against this with the unsaved-form-input exclusion (see below).

## What does not matter

Suspension is not hidden or secret. Your tabs don't disappear. A suspended tab looks normal in the tab strip: same title, same favicon, same position. You can tell it's suspended only when you look very closely (there's a subtle visual indicator, or you check chrome://discards). There's no placeholder page, no "click here to restore" message, no side-by-side view of active and suspended tabs. It's just a tab that reloads when you open it.

You don't have to suspend tabs to keep them. You can leave a tab open forever and it'll stay open. Suspension is optional. Scalpel only suspends when you ask it to (manually, via the timer, or via keyboard shortcut).

Suspension doesn't save your browsing history or cookies. A suspended tab keeps everything: its history, cookies, local storage, service workers. All of that survives the suspend and reload. Only the active memory footprint is freed.

## Code example

If you wanted to write your own suspender, here's what that API call looks like:

// Suspend (discard) the tab with ID 123
chrome.tabs.discard(123, (tab) => {
  if (tab.discarded) {
    console.log("Tab suspended. URL:", tab.url, "Title:", tab.title);
  }
});

// Restore a suspended tab by reloading it
chrome.tabs.reload(123);
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The discarded property tells you whether a tab is currently suspended. You can query all tabs and filter by that flag to count how many are suspended right now.

## How Scalpel shows it

Scalpel's popup displays a count of suspended tabs in this session. Every time you suspend a tab (manually, via a keyboard shortcut, or automatically from the inactivity timer), the count goes up. When you click a suspended tab, it reloads and the count goes down. The toolbar badge on Scalpel's icon also shows this count so you can see at a glance how many tabs you've freed.

In Scalpel's settings, you can turn on the tab statistics panel to see not just the count but also the estimated memory saved (roughly 85 MB per suspended tab) and a breakdown of what's protected (pinned tabs, audio tabs, sites on your never-suspend list, etc.).