SleepyTabs - Tab Suspender & Manager

Name: SleepyTabs - Tab Suspender & Manager
Rating: 4.85 (20 reviews)
Author: Sato

By: Sato

SleepyTabs is a browser extension that helps you manage browser tabs by automatically putting inactive tabs to sleep to save memory and improve browser performance.

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Install

Features & Capabilities

SleepyTabs automatically suspends inactive tabs to save memory and boost browser performance. It uses the browser's tabs.discard API to unload tabs efficiently while keeping data local to your device.

Key features include automatic tab sleeping, intuitive controls, 10+ themes and wallpapers, a Caffeine List to prevent sites from sleeping, granular configuration, privacy-first operation, cross-browser synchronization, and easy import/export of settings. It also supports pinned, grouped, private, and reader-mode tabs, plus keyboard shortcuts for quick management.

User Growth & Download Statistics

Add-on Privacy & Security Task Management Open Source Developer Tools

By:

Sato

Daily users:

1,548 69

Rating:

4.85

(20)

Version:

1.9.9 Last updated: 2026-05-12

Version code:

6259001

Creation date:

2025-05-27

Risk:

Permissions:

Size:

256.46KB

Email:

sp*****@gmail.com

URLs:

Website

Full description:

Source:

Firefox Add-ons Store

Data ingested on:

2026-06-19

Compare stats and ranking:

Ranking

# 2,569 ▲ 69

Other rankings

#231 in Tabs ▲ 11

#9 in spend keyword 37 ▼ 1

#27 in wa sender keyword 31 ▼ 1

#41 in restore tabs keyword 36

#44 in new tabs keyword 42 ▲ 1

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For Developers

Monetize with App Pass Boost with Extension Booster

Contact the developer

Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.

Developed by:

Sato

Firefox Add-ons Store

https://addons.mozilla.org/firefox/addon/sleepy-tabs/

Email:

sp*****@gmail.com

Website:

https://gitlab.com/satoru8/sleepytabs/-/issues

Permission Change History

2026-01-30: Version 1.6.4 → 1.9.0

Add Permissions: downloads

2025-10-29: Version 1.5.7 → 1.6.0

Add Optional permissions: scripting

2025-10-16: Version 1.4.5 → 1.5.0

Add Permissions: tabGroups

Remove Optional permissions: tabGroups

2025-10-05: Version 1.3.13 → 1.4.0

Remove Permissions: tabGroups

Add Optional permissions: tabGroups

2025-09-29: Version 1.3.7 → 1.3.11

Remove Permissions: activeTab

Add Optional permissions: <all_urls>

2025-09-03: Version 1.2.10 → 1.2.18

Add Permissions: activeTab

2025-08-25: Version 1.2.5 → 1.2.9

Add Permissions: notifications sessions

2025-08-17: Version 1.2.3 → 1.2.5

Add Permissions: tabGroups

2025-07-14: Version 1.1.1 → 1.1.3

Remove Host permissions: <all_urls>

Remove Permissions: scripting

2025-06-21: Version 1.1.0 → 1.1.1

Add Permissions: contextMenus

User Reviews

The add-on is praised for active development, rich feature set, and strong performance (notably RAM savings) and serves well as a Marvelous Suspender replacement. Users highlight a polished UI and useful features like a sidebar and settings sync. However, reliability issues with waking/restoring tabs and occasional tab-state losses exist, along with UX gaps such as manual exclude list entry and non-actionable URLs for reopened discarded tabs.

Pros

Active development and responsive developer support.
Feature-rich with extensive customization options.
Notable RAM savings and performance improvements.
Effective replacement for The Marvelous Suspender with strong functionality.
Easy-to-use interface with solid integration (sidebar, settings sync).

Cons

Wake/restoration can be unstable: tabs may reposition or fail to restore after sleep.
Occasional loss of tab state or 'close tab' errors when waking/discovering pages.
Discarded tabs after the timer expires can be hard to reopen due to non-actionable URLs.
Exclude list management is manual; no quick-add button to whitelist sites.

Recent reviews

Finally, a nicely done extension that won't reload tabs when cycling through them!! Wish I'd heard of it sooner! Thanks to the dev!!

by Ag*****, 2026-04-10

Thanks for this extension, I was using "Tab Suspender Mini" that isn't bad either, but this one it's better. Please fix the [Export] in the "General" tab, it's not working, at least for me. Thanks for the option [Create Custom Theme], but please add the possibility to edit the new created ones, the Export/Import options are working just fine.

by Ne*****, 2026-04-02

by Fi*****, 2026-03-29

View all user reviews ›

Is SleepyTabs - Tab Suspender & Manager Safe?

Risk impact

Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

SleepyTabs - Tab Suspender & Manager requires a few sensitive permissions. Exercise caution before installing.

Risk impact analysis details

Critical Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
Medium ******* ******* ************* ***** *** ** ******* *** **** ******* ****** ******** *******
Medium ****** ********** ** ******** ********** *** ********* ******* ******** ****** ******** ****** ********

Risk likelihood

Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

SleepyTabs - Tab Suspender & Manager is probably trust-worthy. Prefer other publishers if available. Exercise caution when installing this add-on.

Risk likelihood analysis details

High This extension has low user count. Unpopular extensions may not be stable or safe.
Medium **** ********* *** ******* ** *** **** * ******* *** ******* *** *** ** ****** ** *****
Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
Good **** ********* *** **** **** *******