Caption Cleanroom · local caption QA

Free WebVTT caption validator

Paste or choose a WebVTT file to inspect timestamps, overlaps, empty cues, line shape, and a reading-density heuristic entirely in your browser. WebVTT cue identifiers are preserved when converting.

Private local review

No upload, account, analytics, browser storage, or customer-data collection is part of this tool. Warnings are guidance, not accessibility or platform certification.

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Need a format change? Use VTT to SRT conversion or SRT to VTT conversion.