VTT → JSONL
Convert VTT files to JSONL entirely in your browser — no upload, no watermark, no sign-up.
Drop files here
or browse from your device
images · audio · video · documents · archives · up to ~500MB
Your first conversion lands here automatically — saved on this device only, never uploaded.
100% Private
Runs in your browser. No upload.
Instant
No queue, no server roundtrip.
Offline-ready
Works after first load.
Converting VTT captions to JSONL keeps the timings intact while matching the syntax your player, platform or browser actually parses. JSONL (JSON Lines) earns its place here: append-friendly, streamable records for large datasets and ML pipelines. WebVTT is the subtitle format the HTML5 video element expects, adding styling, positioning and metadata cues on top of SRT's structure.
WebVTT is the subtitle format the HTML5 video element expects, adding styling, positioning and metadata cues on top of SRT's structure.
Timings and caption text transfer exactly; only the syntax around them changes. Styling and positioning cues survive when JSONL supports them and are dropped when it does not, and timestamp precision is preserved to the millisecond.
What you gain with JSONL: Append-friendly, streamable records for large datasets and ML pipelines.
Drop your VTT file above and Morphio decodes it locally, then re-encodes it as JSONL using WebAssembly + the browser's native codecs. Nothing is ever uploaded — your files stay on your device. Batch as many files as your machine can handle. See exactly how in-browser conversion works.
Open the VTT to JSONL page, drop your document on the drop zone and press convert. Morphio runs local parsers such as pdf.js that execute in your own tab, so the VTT data never leaves your device and no server ever receives a copy.
Text and structure are read locally, so nothing is retyped, re-uploaded, or sent to an OCR service. Converting VTT to JSONL only rewrites the container and encoding you asked for — the source file on your disk is never modified.
Yes. The free plan covers 10 conversions a day with files up to 200 MB and adds no watermark or sign-up. Morphio Pro ($5/month, or $29 once for lifetime access) removes the daily cap and raises the per-file limit to 5 GB.
No. The content is remapped from VTT into JSONL structurally, so nothing is re-compressed. Only features JSONL has no way to express are left behind.
Yes — drop the whole batch in and each file is processed in turn on your own machine. The practical limit is your device's memory and patience, not a server quota, because nothing is queued anywhere else.
No. The conversion runs entirely inside your browser using WebAssembly, so the file never leaves your device — you can disconnect from the internet after the page loads and it still works.