Local-first by default
The core editor parses and changes local MIDI data inside the browser. This gives you a fast workflow and means opening a file does not automatically send it to Miditor. Our Privacy Policy explains the boundary in detail.
About / The project
About Miditor
Miditor combines a MIDI player, piano-roll editor and audio converter in one focused browser workspace—so musicians can move from listening to editing without uploading a project.
01 — Purpose
MIDI tools without the detour
Miditor exists to make common MIDI tasks immediate. A musician, student, producer or developer should be able to open a standard MIDI file, hear the arrangement, inspect its notes and make useful changes without first installing a full digital audio workstation or creating an account.
The result is a free online MIDI workspace built around the file itself. The online MIDI player provides playback and visualization, while the MIDI editor adds piano-roll editing, track controls, tempo changes, velocity tools and detailed event work.
02 — Principles
How Miditor is designed
Useful before complicated
Miditor brings playback, visualization, piano-roll editing and audio export into one interface. The goal is not to imitate every feature of a studio DAW; it is to make focused MIDI work approachable.
Open-web access
The primary tools work in a modern browser across desktop platforms. Pages are statically rendered for speed and accessibility, while interactive editing runs only where it is needed.
03 — Toolkit
From MIDI notes to finished audio
MIDI contains performance instructions rather than recorded sound. Miditor helps make those instructions understandable: tracks appear on a timeline, notes appear in a piano roll and performance data can be adjusted directly. When a project is ready to leave the MIDI world, the MIDI to WAV converter and MIDI to MP3 converter render playable audio through the browser-based sound engine.
The MIDI to sheet music converter now provides a local notation preview with track selection, rhythm quantization and PNG or print-to-PDF output. More advanced capabilities such as AI-assisted note spelling, tuplets and independent voice cleanup remain research items. We prefer an honest description of what works today over pretending an unfinished feature is available.
04 — Origins
Built on open-source foundations
Miditor continues development from Signal, an open-source MIDI sequencer created by ryohey. The project retains the original MIT License and attribution. That foundation makes a capable browser editor possible and gives the work a transparent technical lineage.
Feedback from real MIDI workflows guides what comes next. If you find a compatibility issue, have a focused feature request or want to understand the project better, visit the Contact Miditor page.
Quick answers
Frequently asked questions
What does Miditor do?
Miditor lets you play, inspect, edit and convert MIDI files in a modern web browser, with a piano roll and local-first processing.
Why is Miditor local-first?
Keeping the main MIDI workflow in the browser improves privacy, shortens the path from opening a file to editing it, and avoids requiring an account for basic tools.
Is Miditor connected to the Signal project?
Yes. Miditor continues development from the open-source Signal MIDI sequencer and retains its MIT license and attribution.