SubFlex is a consumer product built for firefox users who watch streaming video with subtitles.

Yes — SubFlex is free to use.

What platforms does SubFlex run on?

SubFlex runs on the web and embeddable surfaces.

Is SubFlex still active?

Unverified. SubFlex 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 SubFlex?

Similar projects tracked by PulseGate include Subflix, +Sub, and Subtitles.

SubFlex is developed by Extension Flex.

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SubFlex

Name: SubFlex
Author: Extension Flex

mozilla.orgVideo & media players

SubFlex is a Firefox extension that synchronizes and customizes subtitles on streaming videos. It provides multi-point sync anchors, dialogue search and scrubbing, subtitle speed adjustment, and tools for correcting timing drift.

FreeWebEmbeddable

Visit mozilla.org

Overview

7 features

In the Video & media players space, SubFlex takes a focused approach. It focuses on keeping subtitles synchronized with streaming videos when timing drifts or scenes have been cut. SubFlex is a consumer product aimed at firefox users who watch streaming video with subtitles. SubFlex costs nothing to use. It runs on the web and embeddable surfaces.

It is developed by Extension Flex, and it first shipped in 2026. Among its 7 catalogued features are multi-point sync, sync anchors, and dialogue scrubber. The interface is available in 32 languages, including Czech, German, and Greek.

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

Multi-point sync
Sync anchors
Dialogue scrubber
Dialogue search
One-click sync
Speed adjustment
Drift correction

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

Indexed12 Sept · 01:38 UTC
SubFlex - Subtitle Controller verified via Firefox Add-ons
Source: Firefox Add-ons · Open

Frequently asked questions about SubFlex

What is SubFlex?: SubFlex focuses on keeping subtitles synchronized with streaming videos when timing drifts or scenes have been cut. It is catalogued under Video & media players on PulseGate.
Who is SubFlex for?: SubFlex is a consumer product built for firefox users who watch streaming video with subtitles.
Is SubFlex free?: Yes — SubFlex is free to use.
What platforms does SubFlex run on?: SubFlex runs on the web and embeddable surfaces.
Is SubFlex still active?: Unverified. SubFlex 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 SubFlex?: Similar projects tracked by PulseGate include Subflix, +Sub, and Subtitles.Subflix +Sub Subtitles
Who makes SubFlex?: SubFlex is developed by Extension Flex.
When did SubFlex launch?: SubFlex first shipped in 2026.

At a glance

Pricing: Free
Platforms: Web
First seen: 12 Sept 2026
Built for: Firefox users who watch streaming video with subtitles
Model: B2C
Solves: Keeping subtitles synchronized with streaming videos when timing drifts or scenes have been cut.

Registered as

Firefox Add-ons: subflex-subtitle-controller

Developer

Extension Flex

Index record

Indexed: 12 Sept 2026
Lifecycle: Alive
First seen: Sept 2026
Last seen: 12 Sept 2026

Identity audit (13)

Slug: subflex-subtitle-controller-mozilla-org
Lifecycle state recorded: 12 Sept 2026
Verification state: Indexed for public listing
Listing state: Listed: yes
Index status: Included in index
Latest evidence snapshot: 12 Sept 2026
Timeline basis: Indexed-at chronology (no inferred launch/funding milestones).
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: 12 Sept 2026
Canonical URL: https://addons.mozilla.org/en-US/firefox/addon/subflex-subtitle-controller

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