Who should use SubSync Master?

SubSync Master is a consumer product built for people who watch online videos with subtitles.

Is SubSync Master free?

Yes — SubSync Master is free to use.

What platforms does SubSync Master run on?

SubSync Master runs on the web and embeddable surfaces.

Is SubSync Master still active?

Unverified. SubSync Master has not been re-checked since it entered the index, so there is no finding either way — and only a positive finding would say otherwise.

What projects are similar to SubSync Master?

Similar projects tracked by PulseGate include +Sub, SubFlex, and Sync Audio Tabs.

Who makes SubSync Master?

SubSync Master is developed by Ywirju.

When did SubSync Master launch?

SubSync Master first shipped in 2025.

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SubSync Master

Name: SubSync Master
Author: Ywirju

mozilla.orgSubtitles & captions

SubSync Master is a Firefox extension that lets viewers manually adjust subtitle timing to match video playback. It supports online video services and local SRT or VTT subtitle files, including services such as YouTube and Netflix.

FreeWebEmbeddable

Visit mozilla.org

Overview

6 features

In the Subtitles & captions space, SubSync Master takes a focused approach. It focuses on fixing subtitle timing mismatches while watching online videos or using local subtitle files. SubSync Master is a consumer product aimed at people who watch online videos with subtitles. SubSync Master costs nothing to use. It runs on the web and embeddable surfaces.

Behind SubSync Master is Ywirju, and it first shipped in 2025. Key capabilities include subtitle timing adjustment, SRT file support, and VTT file support. The interface is available in 32 languages, including Czech, German, and Greek.

Summary written by a language model from the project’s public pages.

Subtitle timing adjustment
SRT file support
VTT file support
YouTube support
Netflix support
Local subtitle syncing

Built with & integrations

Runs on

BrowserEmbeddable

Trust & compliance

Verified signals

HTTPSPrivacy Policy Terms of ServiceFree tierMulti-languageStore-verified publisher

Legal

Indexing history

What PulseGate has recorded for this listing

Indexed17 Sep · 10:31 UTC
SubSync Master verified via Firefox Add-ons
Source: Firefox Add-ons · Open

Frequently asked questions about SubSync Master

What does SubSync Master do?: SubSync Master focuses on fixing subtitle timing mismatches while watching online videos or using local subtitle files. It is catalogued under Subtitles & captions on PulseGate.
Who should use SubSync Master?: SubSync Master is a consumer product built for people who watch online videos with subtitles.
Is SubSync Master free?: Yes — SubSync Master is free to use.
What platforms does SubSync Master run on?: SubSync Master runs on the web and embeddable surfaces.
Is SubSync Master still active?: Unverified. SubSync Master has not been re-checked since it entered the index, so there is no finding either way — and only a positive finding would say otherwise.
What projects are similar to SubSync Master?: Similar projects tracked by PulseGate include +Sub, SubFlex, and Sync Audio Tabs.+Sub SubFlex Sync Audio Tabs
Who makes SubSync Master?: SubSync Master is developed by Ywirju.
When did SubSync Master launch?: SubSync Master first shipped in 2025.

At a glance

Pricing: Free
Platforms: Web
Built for: people who watch online videos with subtitles
Model: B2C
Solves: Fixing subtitle timing mismatches while watching online videos or using local subtitle files.

Registered as

Firefox Add-ons: subsync-master

Developer

Ywirju

Index record

Indexed: 17 Sep 2026
Lifecycle: Alive
Last seen: 17 Sep 2026

Identity audit (13)

Slug: subsync-master-mozilla-org
Lifecycle state recorded: 17 Sep 2026
Verification state: Indexed for public listing
Listing state: Listed: yes
Index status: Included in index
Latest evidence snapshot: 17 Sep 2026
Timeline basis: Indexed-at chronology. This listing's first-seen date was written by the catalog backfill, not observed here, so it is not treated as a sighting.
Name from: Derived from the project's own page and URL.
Category from: Assigned by a language model.
Summary from: Written by a language model from public pages.
Languages from: Detected by a language model, checked against the page's own declaration.
Last updated: 17 Sep 2026
Canonical URL: https://addons.mozilla.org/en-US/firefox/addon/subsync-master

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