Free MIDI test files and sample generator
A standard MIDI file: note events rather than recorded audio. Generate valid .mid sample files for testing sequencers, players and music tooling.
What is a .mid file?
MID: MIDI Music File. A MIDI file contains no recorded audio at all, only note events, timing and instrument selections, which is why a full song fits in a few kilobytes. That makes it structurally unlike every other audio format.
Why generate a test MIDI file?
- Test a sequencer, DAW import or music-notation tool.
- Verify event parsing and timing resolution.
- Check that audio tooling distinguishes event data from sampled audio.
What you can put inside a .mid file
You get 3 content options for MIDI, so the file holds something meaningful rather than random padding: Melody (scale), Chords, Drum pattern. For MIDI these are alternatives, so choose the one that matches what you need to test.
How a .mid file is identified
Every .mid file begins with 4D 54 68 64, "MThd", a MIDI header chunk. That is what a validator inspecting content rather than the file name looks for.
How the size lands on the exact byte
Text meta events carry the padding. Every note event is a fixed size, so the track length is arithmetic rather than a search.
Negative testing with broken MIDI files
- Invalid. Identifiable, but wrong inside, so it fails during parsing.
- Corrupted. The leading bytes are destroyed, so the
4D 54 68 64identifying a .mid is gone. Same length as the valid file. - Incomplete. Truncated part-way, so it is genuinely shorter.
- Empty. Chosen under Content rather than File Condition: valid structure, no data.
Which failure to reach for, and what to assert for each, is covered in how to make a corrupted file for testing. For upload limits and type checks see testing file upload validation.
Sample MIDI content
[MID], MThd header chunk (format 0, 96 ticks) + MTrk note events.
This shows the shape of the file. Your download is generated fresh at the size you choose, so the values will differ.
How to open and verify the file
Play in Windows Media Player or VLC; open in a DAW or MuseScore to see the notes.
Media type audio/midi · extension .mid · category Audio
Generate a .mid file → · questions about sizes, privacy or cost are answered on the site FAQ.
Frequently asked questions about MIDI files
What identifies a .mid file?
A .mid file begins with the bytes 4D 54 68 64, "MThd", a MIDI header chunk. Those bytes are what a content-sniffing validator looks for, and what the Corrupted condition destroys.
How can a .mid file be an exact number of bytes?
Text meta events carry the padding. Every note event is a fixed size, so the track length is arithmetic rather than a search.
What can go inside the MIDI file?
There are 3 content options for .mid: Melody (scale), Chords, Drum pattern. For MIDI these are alternatives, so pick the one matching what you need to test.
Can I download several broken MIDI files at once?
Yes, select more than one File Condition and you get one ZIP containing a .mid per condition, each named after its condition.
Can the MIDI file use UTF-16 or a byte-order mark?
No, and deliberately. A .mid file is a container rather than plain text, so rewriting its bytes as UTF-16 would not produce a UTF-16 document. It would produce a broken file. Use a text format such as CSV, JSON or XML for encoding tests.
How do I open or verify the MIDI file?
Play in Windows Media Player or VLC; open in a DAW or MuseScore to see the notes.