Free · Linux · No install

Get the subtitles.
Skip the video.

Paste a YouTube URL, pick a language and a format, get a subtitle file. That's the whole app. The video is never downloaded, skip_download is hardcoded on.

Castmorphic Subtitles showing a fetched video's language list on the left and format picker with an SRT, VTT, TXT, and Raw choice on the right

Small on purpose

No account, no telemetry, no browser required. One window, one job.

Four formats, one download

Pick the one that fits what you're doing with it.

SRT
Standard subtitle file with timestamps. Works everywhere.
VTT
WebVTT, the format most web video players expect natively.
TXT
Plain transcript. Timestamps and formatting stripped out, just the words.
Raw
Whatever YouTube actually served, unconverted.

Questions

Does it download the video as well?

No. Only the subtitle track is fetched. Skipping the video download is hardcoded on in the app and cannot be switched off, so nothing large is ever requested from YouTube or stored on your machine.

What subtitle formats can it save?

Four. SRT is the standard timestamped subtitle file. VTT is WebVTT, which web video players expect. TXT is a plain transcript with the timestamps stripped out. Raw is whatever YouTube served, unconverted.

What does it need installed to run?

Only python3, version 3.10 or newer, which current Linux desktops already ship. The window, the browser engine and the Python packages all travel inside the AppImage, so there is nothing to install and no Docker or account involved.

Download Castmorphic Subtitles

Single AppImage. No install, no Docker, no account.

Self-contained: the window, the browser engine and the Python packages all ship inside the AppImage. Needs only python3 (3.10+), which every current Linux desktop already has. Full details and source on the GitHub repo.