Check a supplied subtitle file

Supported: .srt, .vtt, and .webvtt text files. Current browser-local limits: 5 MiB and 10,000 cues.

Or drag and drop one supported subtitle file here.

Privacy: Analyzed in this browser; subtitle contents are not sent to our application server in the default workflow.

Synthetic example created for Subtitle Preflight; CC0

Findings

No subtitle loaded

No subtitle loaded

Choose a file, paste subtitle text, or load a synthetic sample to see cue-level findings here. Export becomes available after analysis succeeds.

Ready for a subtitle fileChoose an SRT or WebVTT file, paste subtitle text, or load a synthetic sample.
Technical/readability preflight only — not certification or a substitute for media review.

The checker does not compare subtitles with audio or video and cannot verify accuracy, completeness, speaker identification, meaningful sounds, visual placement, accessibility or legal conformance, or client/platform acceptance.

What the checker reviews

SRT index sequence, timestamp syntax and order, overlap, minimum gaps, duration, CPS, WPM, line count, characters per line, empty cues, and adjacent duplicate text. WebVTT adds header, cue timing, malformed-block, and unsupported-setting diagnostics for the declared subset.

Choose and verify the rule profile

General readability v1.0 is an accepted product default with visible provenance and date. Edit thresholds for the applicable workflow, then rerun to clear stale results.

Review findings, not a universal pass score

Severity uses an icon, label, and text explanation rather than color alone. Responsive finding cards retain cue, timing, observed value, threshold, profile, explanation, and stable identifiers at desktop and mobile widths.

Export the evidence

CSV and HTML exports are generated locally and disabled until a fresh result exists.

Frequently asked questions

Does the checker edit my subtitles?

No. The workflow is non-destructive and report-only.

What happens with malformed blocks?

Recoverable parser diagnostics identify the source line while valid cues can still be reviewed.

Where are reports stored?

Only where your browser downloads them. There is no hosted report in the MVP.