Chart Editor

Create custom charts, import osu!mania beatmaps, and package tracks for distribution.

UPDATED Sep 23, 2026

The built-in chart editor lets you compose and test beatmaps directly in your web browser. Because the editor shares the core gameplay renderer, you can inspect note placement, test audio synchronization, and verify density without leaving the interface.

Creating a new chart

  1. Select CHART EDITOR from the game menu.
  2. Load an audio file in MP3, OGG, or WAV format.
  3. Configure the base BPM and starting offset, then snap the initial downbeat to the waveform.
  4. Place tap notes, extend hold durations, and adjust beat subdivisions such as 1/4, 1/8, 1/12, or 1/16.
  5. Save the chart to local browser storage.

Draft charts saved in your browser are marked as local charts. You can play them in single-player mode at any time. Local charts cannot be picked in multiplayer rooms because other players do not have the corresponding audio and chart data on their devices.

Importing osu!mania beatmaps

You can import existing charts by dragging and dropping .osz, .zip, or .osu files directly into the Rhythmio window:

  • The importer parses timing points, scroll velocity changes, tap notes, and long notes automatically.
  • Key modes from 4K up to 8K are recognized and converted into native Rhythmio difficulty profiles, labelled by lane count (such as HARD 4K or INSANE 7K).
  • Imported audio and background assets are cached in browser storage for instant loading.

Chart packaging and multiplayer sharing

Exporting a chart produces a standard package containing audio files and a beatmap.json manifest:

{
  "title": "Song Title",
  "artist": "Artist Name",
  "bpm": 175,
  "offset": 45,
  "difficulties": [
    {
      "name": "EXPERT 4K",
      "keyCount": 4,
      "noteCount": 1420,
      "hash": "a8f3b2c..."
    }
  ]
}

The manifest includes a cryptographic hash for each difficulty. In multiplayer lobbies, the server compares this hash across all connected players. When every participant has the identical hash, the host can select the chart for competitive play.