Join multiple videos into one locally - in the chosen order, no upload.
Running locally on your device ...
Running locally on your device ...
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Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
Join several recordings into one compilation, combine clips from one recording session, or just make two videos playable back-to-back - this tool stitches the dropped videos together in the chosen order.
Important and honest: every video must share the same picture size - mismatched sizes would need either distortion or black bars, both a silent quality compromise this tool deliberately avoids. If the sizes do not match, the tool reports that clearly as an error.
Everything runs locally in the browser with mediabunny (MPL-2.0, self-hosted, no third-party CDN) on the browser's native WebCodecs API. Your videos are not uploaded.
Many online video mergers upload each file to a server, cap the number or total length of clips on the free tier, or stamp a watermark on the result. Here, merging runs unlimited, free and without a watermark, because everything happens locally in the browser - on any device with a current, WebCodecs-capable browser.
| Input formats | MP4, M4V, MOV, MKV, WEBM |
|---|---|
| Output format | MP4 |
| Batch processing | Yes |
| Processing | Locally in your browser (WebCodecs) |
| File upload | None |
Limitations: Every video must share the same picture size (no automatic cropping or scaling). Full re-encode, so it takes longer than a pure stream copy. Each file ~600 MB limit individually, ~1.2 GB in total (the browser tab's memory limit: because merging decodes and re-encodes several videos at the same time, streaming does not help here the way it does for single-file tools; the 1.2 GB total follows from both files needing to sit in memory at once).
No. The whole merge happens locally in your browser.
Yes, as long as the picture size matches - MP4, MOV, MKV and WebM can be mixed.
The tool honestly refuses with a clear error message instead of distorting or adding bars.
Yes, provided an audio track exists and the browser has a matching codec for it.
A small, usual re-encoding loss is unavoidable because the videos are recomposed.
Yes, in any current mobile browser with WebCodecs support - the files stay just as local as on desktop.
No to both. No account, no watermark - only the total video size is bounded by your device memory.
Yes. They are not uploaded, only assembled locally in the browser - that works even in airplane mode.
Trim video · Convert video · Replace video audio · Video thumbnail · Video watermark · Video speed