Open Subtitles

Add subtitles to any HTML5 video sites such as Youtube, Netflix, Amazon Prime Video, Disney+, HBO Max and other stream sites.

Open Subtitles is a powerful Chrome extension designed to enrich your viewing experience across popular HTML5 video streaming platforms like YouTube, Netflix, Amazon Prime Video, Disney+, HBO Max, and many more. It automatically detects video titles and fetches matching subtitles from OpenSubtitles.com, enabling seamless subtitle integration on your favorite streaming sites.

Key features include support for multiple subtitle formats (*.srt, *.vtt, *.ass, *.ssa), drag-and-drop custom subtitle files, subtitle synchronization, and full customization of subtitle appearance including color, background, transparency, and font size. The extension also works on embedded iframes, allows transcription and text copying, and supports quick navigation through timestamps. Simply install and pin the extension, open a video, and enjoy enhanced subtitle functionality with just a click.

By:
stefan.breitenstein
Daily users:
2,243+ 12
Rating:
3.77
(13)
Version:
6.3.8 Last updated: 2023-10-02
Version code:
5631238
Creation date:
2022-05-18
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:
657.85K
URLs:
Website
Full description:
See detailed description
Source:
Firefox Browser Add-ons
Updated:
a day ago

Other platforms

Open Subtitles (v6.3.8)
10,000+ 3.64 (22)

User reviews

Users praise Open Subtitles for effectively adding subtitles to videos lacking them, especially on ad-free streaming sites like bilibili, offering useful features and ease of use. Common issues include subtitle desynchronization caused by ads interrupting videos, lack of robust subtitle timing offset adjustments, and overlapping text when font sizes are increased. Some sources may not work with the add-on. Overall, it is valued for its core functionality but struggles with timing sync where ads disrupt playback.
Pros
  • Works well for streaming videos without ads, especially on sites like bilibili.
  • Allows playing local subtitle files over remote videos, enabling subtitles where none exist.
  • Simple and effective for movies missing subtitles.
  • Works perfectly with many useful features.
  • Helps users watch videos with missing subtitles by combining video and subtitles from different sources.
Cons
  • Subtitles get out of sync when videos have ads because the add-on does not adjust subtitle timing for ads.
  • No built-in way to adjust subtitle offset time (only minor adjustment available) to fix sync issues.
  • When subtitle font size is increased, two-line subtitles may overlap, reducing readability.
  • Doesn't work on certain sources/websites, possibly due to compatibility issues.
Recent reviews
by Rob Bednark, 2025-04-05


View all user reviews ›

Extension safety

Risk impact

Open Subtitles 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.
  • Low ******* ****** ** *** ********* ******** ********************
Risk likelihood

Open Subtitles 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 **** ********* *** **** **** *******
Upgrade to see full risk analysis details

Compare add-ons

Similar add-ons

Here are some Firefox add-ons that are similar to Open Subtitles:

Popular extensions / apps

Here are some popular extensions / apps that you might be interested in: