Subby

Play your own subtitles (VTT/SRT) over any HTML5 video on any website.

Subby puts your own subtitles on any video, on any website. Watching a lecture, talk, or clip that has no captions — or the wrong ones? Drop in a subtitle file and Subby overlays it right on top of the player. It works on virtually any HTML5 video (lecture tools like echo360 and Panopto, course platforms, and most streaming sites), even fullscreen. Load your subtitles • Supports SubRip (.srt), WebVTT (.vtt), and SubStation Alpha (.ass / .ssa) • Open from the popup, or just drag the file onto the page • Got more than one video on the page? Pick which one to caption Make them look right • Font size, font family, and text colour • Smooth, rounded outline with adjustable colour and width • Background colour and opacity • Position top, middle, or bottom — or drag the subtitle anywhere on the video • Add your own font files (.ttf/.otf/.woff/.woff2) and use them instantly Get them in sync • Nudge the timing offset with a slider or keyboard shortcuts ([ and ]) • Live preview shows the lines around the current moment • Tap-sync: click the instant a line is spoken to line everything up • Sync Subtitle Speed: mark an early line and a late line to fix subtitles that slowly drift out of sync (wrong-framerate files) • Your sync is remembered per page, so it’s ready next time Your privacy comes first Subby keeps everything on your device. Your settings and subtitle files never leave your computer — no accounts, no tracking, no analytics, nothing sent to any server. Free and open. If it saves you some time, you can buy me a coffee from the popup. ☕