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WAV to MP3 API

Convert wav files to mp3 with a single POST request. Upload a file as multipart/form-data and the API returns a download URL for the converted file.

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Input

wav

Output

mp3 (audio/mpeg)

Credit cost

2 per file

Max file size

Per plan (10–500 MB)

Endpoint

POSThttps://api.fileswitch.co/api/v1/converter/wav-to-mp3

Authentication 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 2 credits 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.

Example request
curl -X POST https://api.fileswitch.co/api/v1/converter/wav-to-mp3 \
  -H "Authorization: Bearer fc_YOUR_API_KEY" \
  -F "file=@input.wav" \
  -F "bitrate=192k" \
  -F "sampleRate=0" \
  -F "channels=0"

Parameters

Send file plus any optional options. Every option is optional and falls back to its default when omitted.

FieldTypeDefaultDescription
filebinary—The file to convert. Accepts .wav
bitratestring192k

Output audio bitrate; ignored for WAV output.

Values: 320k, 256k, 192k, 128k, 96k, 64k

sampleRatenumber0

Output sample rate in Hz; 0 keeps the source rate.

Range: 0 .. 192000

channelsnumber0

Output channel count; 0 keeps the source channels.

Range: 0 .. 8

Example request bodyjson
{
  "file": "input.wav",
  "bitrate": "192k",
  "sampleRate": 0,
  "channels": 0
}

Response

Every conversion endpoint returns the same success / message / data envelope. The data object is a Conversion record with a temporary downloadUrl.

Response bodyjson
{
  "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

MP4 to GIF

mp4 gif

MP4 to MP3

mp4 mp3

MP3 to WAV

mp3 wav

FLAC to MP3

flac mp3

Ready to convert wav → mp3? Start free — no credit card required.

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