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OpenSubs

Free plan ExtensionLinuxMacWebWindows

What OpenSubs is

OpenSubs is a freemium subtitle tool that transcribes, translates, styles, and burns captions into video, with processing performed in the browser. It accepts MP4, MOV, WebM, and MKV files. Whisper runs locally through WebGPU when available or WebAssembly otherwise, using Tiny, Base, or Small models. Translation covers 20 languages through Chrome’s on-device translation, user-provided provider keys, or paid cloud credits; Claude, OpenAI, and DeepL are named providers. Users can choose 12 subtitle styles, apply word-by-word highlighting, burn captions into MP4, or export SRT, VTT, and ASS files. The free plan costs nothing, billed forever, with no file-size limit or watermark. The Credits plan costs $5 a month for 1,000 credits. Browser extensions cover Chrome, Edge, and Firefox, and desktop builds exist for macOS, Windows, and Linux.

Who it suits

It suits creators who need browser-based transcription, translated captions, styled subtitles, or burned-in video. Extension and desktop options also support tab playback and local workflows.

What it does well

Processes video in the browser
Supports 20 caption languages
Offers 12 styles and word highlighting
Exports SRT, VTT, and ASS
Free plan has no file-size limit or watermark

What to know first

Cue timings and structure cannot be edited
Brand caption presets are unavailable
Desktop builds are unsigned release candidates
Cloud translation can send text or audio off-device

Plans

Plan	Billed and limits	Price
Free	forever · Speech recognition in browser · On-device translation · 12 styles · Word-by-word highlighting · Trimming and resolution control · MP4 burn · SRT, VTT and ASS export · No file-size limit or watermark	Free
Credits	for 1,000 credits · Cloud translation on OpenSubs’ backend · Credits never expire · Failed jobs cost nothing	$5, paid once

As opensubs.app lists them, read 11 Oct 2026. The maker's own page has the final word.

Verdict

OpenSubs provides local-first caption creation with broad format support, styling, and exports. Its free plan covers core tools, while credits support paid cloud translation.

Facts from OpenSubs's own pages

API key handling: User-provided API keys are held in page memory and are not stored or sent to OpenSubs, according to the site. · opensubs.app, 11 Oct 2026
Brand caption presets: No · opensubs.app, 22 Sept 2026
Browser extension: A free extension generates subtitles over video playing in a tab in Chrome, Edge and Firefox. · opensubs.app, 11 Oct 2026
Burn-in captions: Yes · opensubs.app, 22 Sept 2026
Caption languages: 20 · opensubs.app, 22 Sept 2026
Caption styling: Yes · opensubs.app, 22 Sept 2026
Desktop and CLI: Free desktop builds are offered for macOS, Windows and Linux; the command-line tool is built from source, and both require ffmpeg with the ASS filter for burning. · opensubs.app, 11 Oct 2026
Editing limit: Cue text can be edited, but cue timings cannot be changed and cues cannot be added, deleted or merged. · opensubs.app, 11 Oct 2026
Free plan: Yes · opensubs.app, 22 Sept 2026
Integrations: The site names Claude, OpenAI and DeepL as providers usable with a user’s own API key; keys are sent directly from the browser to the selected provider. · opensubs.app, 11 Oct 2026
Offline use: After initial downloads, the site says it works largely offline except for cloud translation. · opensubs.app, 11 Oct 2026
Privacy: The site says it has no video upload endpoint; subtitle text or trimmed audio can leave the device only when the user selects a cloud option. · opensubs.app, 11 Oct 2026
Purpose: OpenSubs transcribes, translates, styles and burns subtitles into video, with video processing running in the browser. · opensubs.app, 11 Oct 2026
Release status: The site identifies current builds as release candidates and says desktop builds are unsigned. · opensubs.app, 11 Oct 2026
Styling and export: OpenSubs offers 12 subtitle styles, word-by-word highlighting, MP4 burn-in and SRT, VTT and ASS export. · opensubs.app, 11 Oct 2026
Subtitle export: other formats · opensubs.app, 22 Sept 2026
Support: The site lists [email protected] for contact and problem reports. · opensubs.app, 11 Oct 2026
Transcription: It runs Whisper locally using WebGPU when available or WebAssembly otherwise, with Tiny, Base and Small models. · opensubs.app, 11 Oct 2026
Translation: It supports translation into 20 languages, using Chrome’s built-in on-device translation, user-provided provider keys or paid cloud credits. · opensubs.app, 11 Oct 2026
Video formats: The browser app accepts MP4, MOV, WebM and MKV videos. · opensubs.app, 11 Oct 2026

Where OpenSubs stands on Freedom251

AI Video Caption Generators#41 of 99