FLAC to MP3 Converter

Convert lossless FLAC audio to MP3 with bitrate, resampling, and channel controls

file· File resultOpen tool

Quick start

Call this tool from your code in three languages.

cURL

# 1) Request a presigned URL → returns { uploadUrl, storageKey }
curl -X POST 'https://api.elysiatools.com/api/upload/presign/flac-to-mp3' \
  -H 'Content-Type: application/json' \
  -d '{"filename":"audioFile.ext","contentType":"application/octet-stream","size":12345}'

# 2) PUT the file bytes directly to the presigned uploadUrl
curl -X PUT '<presigned uploadUrl>' \
  --data-binary @/path/to/file.ext

# 3) Call the tool, passing the returned storageKey for each file field
curl -X POST 'https://api.elysiatools.com/en/api/tools/flac-to-mp3' \
  -F 'audioFile=uploads/2026/01/01/your-tool-1700000000000-abc123.ext' \
  -F 'bitrate=192' \
  -F 'sampleRate=auto' \
  -F 'channels=auto' \
  -F 'keepMetadata=true'

API reference

Send a POST request with your inputs as JSON. File parameters require a separate upload first.

Endpoint

HTTP

POST https://api.elysiatools.com/en/api/tools/flac-to-mp3

Parameters

Name	Type	Required	Description
audioFile	fileupload required	Yes	Upload a FLAC file to convert to MP3
bitrate	select	No	—
sampleRate	select	No	—
channels	select	No	—
keepMetadata	checkbox	No	—

File-type parameters must be uploaded first via POST /upload/flac-to-mp3, then the returned filePath is passed to the corresponding file field.

Response format

File result

JSON

{
  "filePath": "/public/processing/randomid.ext",
  "fileName": "output.ext",
  "contentType": "application/octet-stream",
  "size": 1024,
  "metadata": {
    "key": "value"
  },
  "error": "Error message (optional)",
  "message": "Notification message (optional)"
}

MCP integration

Add this tool to your Model Context Protocol server so AI agents can list and call it.

Server configuration

Add this block to your MCP client configuration:

mcp.json

{
  "mcpServers": {
    "elysiatools-flac-to-mp3": {
      "name": "flac-to-mp3",
      "description": "Convert lossless FLAC audio to MP3 with bitrate, resampling, and channel controls",
      "baseUrl": "https://api.elysiatools.com/mcp/sse?toolId=flac-to-mp3",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

List available tools

After connecting to the SSE endpoint, list the exposed tools:

tools/list

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/list"
}

Call this tool

Invoke the tool by its id, passing arguments built from its parameters:

tools/call

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {
    "name": "flac-to-mp3",
    "arguments": {
  "audioFile": "https://example.com/file.ext",
  "bitrate": "192",
  "sampleRate": "auto",
  "channels": "auto",
  "keepMetadata": true
}
  }
}

Chain multiple tools in one session with a comma-separated toolId list, e.g. /mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp (max 20).

File parameters accept a public file URL only (https://…). Local paths, data: URIs, and Base64 strings are not supported.

Questions or issues? Contact [email protected]