Audio Joiner
Merge MP3, WAV, M4A, FLAC, OGG, and OPUS files into one track, in the order you choose. Mixed formats are fine; everything is aligned before joining. Runs in your browser, and your files never leave it.
Merge audio without handing it to a server
Joining files is usually a chore that ends with an upload form: pick files, send them to someone's server, wait in a queue, download the result. This tool skips all of that. FFmpeg (the same open-source engine inside most audio software) runs in your browser through WebAssembly, so the merge happens on your own machine. We never see your files, so we can't store them, leak them, or train on them. Voice memos, lecture recordings, demo takes: they stay yours.
Mixed formats join cleanly
Real folders are messy: an MP3 from one app, a WAV export, an M4A voice memo. The joiner decodes every file and aligns them to a common sample rate and channel layout before merging, so mixed sources become one consistent track instead of a file that jumps in volume or speed halfway through. Drag the order you want, top to bottom, then export.
The honest quality note
A merge means one re-encode into your chosen output format. Export WAV, FLAC, or AIFF and that encode is lossless, nothing is thrown away. Export MP3, M4A, OGG, or OPUS and you spend one generation of lossy encoding; at 320 kbps it stays inaudible for most listeners. What to avoid is joining, splitting, and re-joining lossy files repeatedly, because each pass stacks another small loss.
Audio joiner: common questions
Are my audio files uploaded to a server?
No. The joiner is FFmpeg compiled to WebAssembly, running inside your browser. Your files never leave your device; we never see them, store them, or train on them.
Can I join files with different formats or sample rates?
Yes. Each file is decoded and aligned to a common sample rate and channel layout before joining, so an MP3, a WAV, and a voice memo can merge into one clean track.
Does joining reduce the audio quality?
The joined track is re-encoded once in your chosen format. Export WAV or FLAC for zero loss, or MP3 and M4A at 320 kbps to keep any difference inaudible for most listeners.
How many files can I join?
There is no fixed limit; the practical bound is your device's memory since everything is processed locally. Joining a dozen typical songs or a folder of voice memos is no problem.
Who makes this?
We're the small team behind Xport Studio, a private, fully offline app for AI vocals, stems, and mastering. These free tools are side experiments we wanted to share. No upsell, but if you're curious about the bigger thing, take a look.