Convert MP3 to JSON Online Free

Drag & drop your .mp3 file here, or click to browse

Converts to JSON on secure servers · 1 free a day, files up to 25 MB · no signup

Your first conversion each day is free (files up to 25 MB). A $2.99 one-time Day Pass unlocks 24 hours and ends by itself.

Extract the technical metadata and ID3 tag data of any MP3 file as structured JSON — title, artist, album, bitrate, sample rate, duration, and stream details. Powered by ffprobe.

By ChangeThisFile Team · Last updated: October 2026

Quick Answer

ChangeThisFile turns an MP3 into a JSON description of the file: ID3 tags (title, artist, album), codec, bitrate, sample rate, channels, and exact duration. It runs ffprobe on our server and returns ffprobe's own -show_format -show_streams JSON, so existing ffprobe parsers work unchanged. It does not transcribe speech or export the waveform. Your first conversion each day is free for files up to 25MB; a $2.99 Day Pass covers more conversions and files up to 100MB.

First daily conversion free No signup required Encrypted transfer · Async jobs kept up to 24h Queued when needed Updated October 2026

MP3 Audio vs JSON: Format Comparison

Key differences between the two formats

Feature	MP3	JSON
Type	Binary audio container with ID3 metadata	Plain-text structured data
Purpose	Store compressed audio with embedded tags	Describe key/value hierarchies
Human-readable	No — binary payload	Yes — opens in any text editor
Contains	MPEG audio frames, ID3v1/ID3v2 tags, optional cover art	Strings, numbers, arrays, nested objects
File size	Several MB per song	A few KB of metadata
Use case	Music playback and distribution	Library indexing and tagging workflows
Compatible with	Every media player and device	Every programming language

When to Convert

Common scenarios where this conversion is useful

Audit tags across a music library

Export each MP3's ID3 tags to JSON and check them in a script or spreadsheet for missing artists, albums or years. This route is read-only; fix the tags in a tag editor.

Validate podcast deliveries

Confirm an MP3 episode meets a podcast network's spec — 44.1 kHz, stereo, 128 kbps or higher — by inspecting the JSON before uploading.

Build a searchable audio archive

Pipe MP3 metadata into a database to power search and filtering by artist, album, year, or duration without scanning the audio every time.

Verify download integrity and tagging

After downloading or transferring MP3 files, confirm the bitrate, sample rate, and tag completeness against a manifest using the JSON output.

Diagnose audio quality issues

Inspect the codec profile and bitrate of an MP3 to find out whether it was re-encoded from a lower-quality source or transcoded multiple times.

Who Uses This Conversion

Tailored guidance for different workflows

Developers

Convert MP3 config files to JSON for compatibility with different tools or frameworks
Transform MP3 API responses to JSON for debugging, logging, or documentation

Validate the converted JSON output with a linter to catch any structural issues from the conversion

Watch for data type coercion (e.g., numbers becoming strings) when converting between MP3 and JSON

Data Analysts

Convert MP3 exports to JSON for importing into spreadsheet software, databases, or BI tools
Transform MP3 datasets to JSON for sharing with teammates who use different analysis tools

Check that column delimiters and quote escaping are handled correctly in the converted JSON file

Preview the first few rows of the JSON output to verify headers and data alignment

System Administrators

Convert MP3 configuration to JSON when migrating between infrastructure tools or platforms
Transform MP3 log exports to JSON for ingesting into monitoring or analysis systems

Back up the original MP3 config before converting, especially for production systems

Test the converted JSON in a staging environment before deploying to production

How to Convert MP3 Audio to JSON

1

Upload your MP3 file

Drag and drop your .mp3 file onto the converter, or click to browse. The free tier accepts files up to 25MB; eligible paid browser access accepts up to 100MB.
2

Server-side metadata extraction

Your file is uploaded over an encrypted connection and inspected with ffprobe. ID3 tags, codec, bitrate, duration, and sample rate are serialised as JSON.
3

Download the JSON

Click Download to save the resulting .json file. Your original MP3 is automatically deleted from our servers after processing.

Automate this conversion

Convert MP3 Audio to JSON via API

Integrate this conversion into your pipeline with 3 lines of code. Free tier: 25 conversions/month.

curl -X POST https://changethisfile.com/v1/convert \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "file=@input.mp3" \
  -F "target=json" \
  -o output.json --fail

const form = new FormData();
form.append('file', fileInput.files[0]);
form.append('target', 'json');

const res = await fetch('https://changethisfile.com/v1/convert', {
  method: 'POST',
  headers: { 'Authorization': 'Bearer YOUR_API_KEY' },
  body: form
});
const blob = await res.blob(); // your converted JSON file

Replace YOUR_API_KEY with your free key — no credit card needed.

Get a free API key

Frequently Asked Questions

What does the MP3 to JSON output look like?

Two top-level keys, "streams" and "format". A 3-second test MP3 returned "codec_name": "mp3", "sample_rate": "44100", "channels": 1, "duration": "3.030204" and "bit_rate": "129393", with its ID3 tags under format.tags: {"title": "Test Tone", "artist": "ChangeThisFile", "album": "Samples"}. Field names are exactly ffprobe's.

Does this convert the audio itself to JSON?

No. The JSON describes the file; it contains no audio samples and no transcript. For speech as text you need a transcription tool such as Whisper. Its JSON output (a segments array with start, end and text) can then be turned into subtitles with the JSON to SRT converter.

Which ID3 tag versions are supported?

ffprobe reads both ID3v1 and ID3v2 tags, including extended ID3v2.3 and ID3v2.4 frames. All recognised tags appear under the format.tags object in the JSON output.

Are cover art images included in the JSON?

Embedded album art is detected and listed as an attached_pic stream, but the image bytes themselves are not inlined into the JSON. Use the MP3 to JPG or MP3 to PNG converter if you want to extract the artwork.

Is the MP3 to JSON conversion free?

Your first conversion each day is free, with no signup and no watermark, for files up to 25MB. For more conversions the same day or files up to 100MB, a one-time $2.99 Day Pass unlocks unlimited conversions for 24 hours. No account or subscription is needed.

Are my files kept private?

Yes. Files up to 15MB are deleted as soon as the converted file is sent back; larger files run as a background job and are deleted automatically about a day later.

What does the output look like?

The JSON has two top-level objects: 'format' (container info, duration, bit_rate, and a 'tags' object with ID3 values) and 'streams' (an array describing each audio stream). This matches the standard ffprobe -show_format -show_streams JSON schema.

Can I parse the JSON in code?

Yes. The output is plain JSON. Use JSON.parse() in JavaScript, json.load() in Python, or any JSON parser in your language of choice.

Will the JSON tell me if my MP3 is variable bitrate?

Yes. ffprobe reports the average and overall bitrate, and you can detect VBR by the difference between bit_rate and the stream-level bit_rate. The codec_long_name will also show 'MP3 (MPEG audio layer 3)' with frame layout details.

Does this work on mobile?

Yes. The converter runs in any modern mobile browser. Upload an MP3 from your device and download the JSON directly.

What if my file is not a valid MP3?

If ffprobe can't parse the file, the converter returns an error rather than partial metadata. Re-export from your editor or DAW and try again.

Can I get the same JSON without uploading?

Yes, if FFmpeg is installed: ffprobe -v quiet -print_format json -show_format -show_streams song.mp3 > song.json produces the same JSON this page returns. The web converter exists so you don't have to install anything.

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