Features & Capabilities

+Sub is a powerful Chrome extension designed to enhance your video-watching experience by allowing you to load subtitles on any HTML5 video easily. Whether watching on Netflix, Amazon Video, YouTube, or embedded players in blogs, you can quickly add subtitles with just a few clicks.

The extension features a built-in subtitle search powered by TMDB and OpenSubtitles, enabling you to find your preferred subtitles in multiple languages. Alternatively, you can upload subtitle files from your local machine in popular formats such as *.srt, *.vtt, *.ass, and *.ssa. +Sub also offers synchronization capabilities, letting you adjust subtitle timing directly through an intuitive offset interface.

Beyond displaying subtitles, +Sub can show transcript text that is copyable and interactive—clicking on transcript segments jumps to corresponding video timestamps. For developers and power users, +Sub supports videos within iframes and provides open source access through its GitHub repository. Join the community on Slack for support and discussion.

User Growth & Download Statistics

Manifest V2 Add-on
By:
stefan.breitenstein
Daily users:
510 7
Rating:
4.38
(16)
Version:
6.5.6 Last updated: 2024-01-16
Version code:
5678262
Creation date:
2018-11-15
Risk:
Moderate risk impact Low risk likelihood
Permissions:
  • activeTab
  • storage
  • https://*.plus-sub.com/*
  • https://gqlos.plus-sub.com/*
  • https://*.opensubtitles.org/**/*
  • https://*.opensubtitles.com/**/*
  • webRequest
Size:
759.63KB
Email:
st*****@gmail.com
URLs:
Privacy policy
Full description:
See detailed description
Source:
Firefox Add-ons Store
Data ingested on:
2026-06-16
Compare stats and ranking:

Other platforms

Chrome
+Sub (v6.5.2)
10,000 3.78 (126)

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:
stefan.breitenstein
Firefox Add-ons Store
https://addons.mozilla.org/firefox/addon/plussub/
Email:
st*****@gmail.com

Permission Change History

2022-11-12: Version 6.2.3 → 6.3.0
Add Permissions: https://gqlos.plus-sub.com/*
Remove Permissions: https://gqldev.plus-sub.com/*

User Reviews

Pros
  • Works well on platforms like Paramount Plus and provides good subtitle timing and management.
  • Small set of permissions required, which enhances user privacy and security.
  • Valuable tool for expats needing subtitles in various languages.
Cons
  • Struggles to function properly on Netflix, with subtitles not displaying correctly in full-screen mode.
  • Frequent loading issues where the add-on does not start or show subtitles, leading to frustration.
  • Inconsistent performance across different platforms, particularly with Dailymotion and others.
Recent reviews
by 敬念*****, 2025-03-29

by 远离*****, 2025-02-19

It has always worked flawlessly, but recently it doesn't load, the waiting circle keeps spinning and nothing happens :( And it was the best plugin of this type.
by Fi*****, 2024-12-10
View all user reviews ›

Is +Sub 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.

+Sub requires a few sensitive permissions. Exercise caution before installing.

Risk impact analysis details
  • High Allows the extension to observe and analyze traffic in flight for the selected hosts.
  • 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.

+Sub has earned a fairly good reputation and likely can be trusted.

Risk likelihood analysis details
  • High This extension has low user count. Unpopular extensions may not be stable or safe.
  • Low **** ********* *** ******* **** **** * ****** **** ***** ******** *** **** ****** ** ** ****** *** *****
  • Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
  • Good **** ********* *** **** **** *******
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Best +Sub Alternatives

Here are some Firefox add-ons that are similar to +Sub: