✳ CAPTIONS · INSTAGRAM REELS
WebVTT captions for Instagram Reels
Caption QA + Instagram Reels compatibility. Drop a WebVTT file to validate it against Instagram Reels's caption rules. Stays on your device.
Instagram Reels · may accept WebVTT (verify with the platform) · post-text limit 2,200 characters
Sidecar .vtt file with timestamps; required by HTML5 <track>.
Source: https://developers.facebook.com/docs/instagram-platform/instagram-api-with-instagram-login/content-publishing/ · Verified 2026-09-12
What this checks
- Format auto-detection (SRT vs WebVTT) and parse errors
- Per-cue reading speed (warnings above 21 chars/sec)
- Negative timestamps and zero-duration cues
- Cue overlap and ordering
- Instagram Reels post-text character limit (2,200)
After validating, create all platform versions in the Creator: /tools/pack
Automate this in Koldflux