🥁 Beat Audio Slicer

Cut an MP3 or WAV on the beat and keep the groove

About this tool

Trim a song so the cut lands on the beat, not on a random millisecond. Drop an MP3 or WAV and the tool detects the tempo straight away, then draws the waveform with the beat grid over it. Drag the two handles (or type the start and end times in seconds) and the marks pull themselves onto the grid: 1/4, 2/4, 4/4 (one whole beat) or a full bar. Play the selection right in the page to hear it before you render, then download the trimmed track as MP3 or WAV. The tempo, the grid and the exact cut times are shown the whole time, so loops and ringtones come out clean on the first try. Free, no signup, no watermark.

Drop an MP3 or WAV. The tempo is detected right away, the beat grid is drawn across the waveform and the snap step appears underneath.

Your track *

⬆ Drag & drop a file here

MP3 or WAV. Nothing is uploaded anywhere - the file is analysed and cut on the server that runs this page.

Waveform and beat grid

Upload a track and the tempo shows up here.

Drag the handles to set the cut, drag the wave to move along, scroll to zoom. The strip at the bottom is the whole track. 🔁 Loop

Drag the two handles to mark the start and the end. Ticks show the detected beat grid; the darker band is what you keep.

Snap to the beat grid

Marks jump to the nearest point of the grid as you drag or type. 4/4 keeps whole beats, which is what most cuts want.

Pick the output format, add a fade if you like, then cut the track.

Output format

MP3 quality

Used only for MP3 output.

Fade in (seconds)

0 leaves the start as it is.

Fade out (seconds)

0 leaves the end as it is. A short fade hides a cut that lands mid-note.

Normalise loudness Even out the loudness (-14 LUFS)

Bring the cut to a steady streaming-style level.

File name (optional)

Leave empty to keep the original name with -beat-cut at the end.

API

POST /api/tools/beat-audio-slicer/run (multipart/form-data) → JSON with outputs[].url, a zip link and a config_url.

Every run also hands you the config JSON (button above). It is the request body - POST it straight back to replay the exact generation:

curl -X POST -H 'Content-Type: application/json' \\
  --data @genbox-config-beat-audio-slicer.json \\
  /api/tools/beat-audio-slicer/run

For AI agents · API specs

Technical specs

Category	video
Slug	`beat-audio-slicer`
Run endpoint	`POST /api/tools/beat-audio-slicer/run`
Content type	`multipart/form-data` (with file uploads) or `application/json`
Response	JSON: `job`, `notes`, `outputs[].url`, `zip`, `config_url`
Rate limit	API: 1 request / minute / IP. Live preview and image renders have their own separate limits, plus a short global cooldown between renders (storm protection). Over a limit you get HTTP `429` + a `Retry-After` header (local requests are unlimited)
Machine-readable spec	`GET /api/tools/beat-audio-slicer`
OpenAPI 3.1 (Swagger)	this tool (JSON) · all tools

Request body

Every parameter accepted by the run endpoint, in request-body order. Fields are optional unless marked required. The same schema is published as OpenAPI 3.1. Upload files with multipart/form-data; a JSON body replays a saved config.

Parameter	Type	Required	Default / allowed values	Description
`audio`	file	required		MP3 or WAV. Nothing is uploaded anywhere - the file is analysed and cut on the server that runs this page.
`waveform`	beatslice	no		Drag the two handles to mark the start and the end. Ticks show the detected beat grid; the darker band is what you keep.
`snap`	select	no	`1/4` · `2/4` · `4/4` · `bar` · `off`	Marks jump to the nearest point of the grid as you drag or type. 4/4 keeps whole beats, which is what most cuts want.
`start_seconds`	number	no	`0`	Second you cut from. Typing a value snaps it to the grid unless snapping is off.
`end_seconds`	number	no	`0`	Second you cut to. 0 means the end of the track.
`format`	select	no	`same` · `mp3` · `wav`
`bitrate`	select	no	`320` · `256` · `192` · `128`	Used only for MP3 output.
`fade_in`	number	no	`0`	0 leaves the start as it is.
`fade_out`	number	no	`0`	0 leaves the end as it is. A short fade hides a cut that lands mid-note.
`normalize`	checkbox	no		Bring the cut to a steady streaming-style level.
`filename`	text	no		Leave empty to keep the original name with -beat-cut at the end.

Call it from an agent

GET /api/tools/beat-audio-slicer - machine-readable spec of this tool (inputs, category, API block).
GET /api/tools - list of every tool plus the categories.
POST /api/tools/beat-audio-slicer/run - run it. Accepts multipart/form-data (with files) or a raw application/json body. Returns JSON with outputs[].url, zip and config_url.
The config_url JSON is the request body - POST it back to replay the same generation.

# agent example
curl -s https://genbox.eu/api/tools/beat-audio-slicer/run \\
  -H 'Content-Type: application/json' \\
  --data @genbox-config-beat-audio-slicer.json

Rate limits

Max 1 request per minute per IP on the run endpoint.
Over the limit you get HTTP 429 with retry_after (seconds) - wait that long and retry.
Higher limits and API keys are coming soon: an API key will lift the per-IP throttle. Not available yet.