Get a styled subtitle file into the one caption format browsers actually accept.
Open a project in the editor and go to Captions. You can start from a video you are captioning, or from nothing at all if you only need the file converted.
Bring in the ASS file. The cues and their timings are read in as they are, so nothing is re-timed and nothing is re-transcribed.
Export as VTT. You can also burn the captions into the video instead if you would rather they could never go missing.
No browser has native support for Advanced SubStation Alpha. If a caption file is going onto a web page through the <track> element, it has to become WebVTT, and there is no configuration that changes that.
The conversion keeps the dialogue and the timings. The styling does not survive in any meaningful way: ASS style blocks, override tags, karaoke timing and precise positioning have no WebVTT equivalent that a browser will render consistently.
If the appearance matters more than the captions being toggleable, burn the ASS file into the video instead and upload a plain MP4. That is usually the right call for anything that was typeset deliberately.
No. The HTML5 <track> element supports WebVTT only, so an ASS file has to be converted or burned into the video.
It is dropped. Fonts, colours, positioning and effects have no reliable WebVTT equivalent, so the output is plain captions with the original text and timings.
Free, in the browser, and the captions can be burned into the video in the same place.