Audio Trim API
Convert mp3, wav, flac, m4a, aac, ogg, opus files to mp3, wav, flac, m4a, aac, ogg, opus with a single POST request. Upload a file as multipart/form-data and the API returns a download URL for the converted file.
Input
mp3, wav, flac, m4a, aac, ogg, opus
Output
mp3, wav, flac, m4a, aac, ogg, opus (audio/mpeg)
Credit cost
1 per file
Max file size
Per plan (10–500 MB)
Endpoint
https://api.fileswitch.co/api/v1/converter/audio-trimAuthentication is optional for guests and recommended for production. Send either an API key or a JWT access token as a Bearer token. Authenticated requests deduct 1 credit from your balance; failed conversions are refunded. See Authentication for details.
Quick start
The same request in every supported language. Each example uploads a file and prints the downloadUrl from the response.
curl -X POST https://api.fileswitch.co/api/v1/converter/audio-trim \
-H "Authorization: Bearer fc_YOUR_API_KEY" \
-F "file=@input.mp3" \
-F "start=0" \
-F "duration=0" \
-F "end=0" \
-F "fadeIn=0" \
-F "fadeOut=0"Parameters
Send file plus any optional options. Every option is optional and falls back to its default when omitted.
| Field | Type | Default | Description |
|---|---|---|---|
| file | binary | — | The file to convert. Accepts .mp3 , .wav , .flac , .m4a , .aac , .ogg , .opus |
| start | number | 0 | Trim start in seconds. Min: 0 |
| duration | number | 0 | Trim duration in seconds; 0 = to the end of the file. Min: 0 |
| end | number | 0 | Alternative end time in seconds; 0 = ignored. Min: 0 |
| fadeIn | number | 0 | Fade-in duration in seconds. Min: 0 |
| fadeOut | number | 0 | Fade-out duration in seconds. Min: 0 |
{
"file": "input.mp3",
"start": 0,
"duration": 0,
"end": 0,
"fadeIn": 0,
"fadeOut": 0
}Response
Every conversion endpoint returns the same success / message / data envelope. The data object is a Conversion record with a temporary downloadUrl.
{
"success": true,
"message": "Conversion completed",
"data": {
"id": "b10a5f2e-8c1e-4b3a-9c1d-2e3f4a5b6c7d",
"inputFormat": "html",
"outputFormat": "pdf",
"inputFileName": "document.html",
"outputFileName": "document.pdf",
"inputFileSize": 45210,
"outputFileSize": 88431,
"status": "completed",
"error": null,
"creditCost": 2,
"downloadUrl": "/api/v1/converter/download/conversions%2Fb10a5f2e-8c1e-4b3a-9c1d-2e3f4a5b6c7d%2Foutput.pdf",
"createdAt": "2026-07-31T13:00:00.000Z",
"completedAt": "2026-07-31T13:00:02.000Z"
}
}Prepend https://api.fileswitch.co/api/v1 to the downloadUrl and download with the same credentials. Files are retained temporarily and auto-deleted. See the full field reference in Response Schema.
Related conversions
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