Music Mastering API

Guide to Using the Music Mastering API

Music Mastering API

The Music Mastering API enables you to quickly build a service to prepare music tracks for distribution. This process removes many technical, time, and cost barriers that come with traditional music mastering. The Music Mastering API provides the functionality to evaluate different mastering profiles, and then create final mastered recordings with optimized loudness that are ready to share on streaming platforms.

Key features:

✓ Simple integration
✓ Free previews of different mastering profiles under fair use policy
✓ Wide file format support
✓ Optimize tonal quality
✓ Accurate loudness targeting
✓ Enhance stereo image

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Why use the Music Mastering API?

Unlike less intelligent methods of equalization, the Music Mastering API carefully analyzes the track and continuously adjusts how it applies the processing over the duration of the track, depending on the characteristics of the music. The music creator can evaluate mastering profiles using previews and adjust the intensity of the profile to further control how much processing is applied in the final master.

The Music Mastering API helps you prepare music to meet streaming service loudness requirements. This gives the music creator more control over how their material is experienced on streaming services. For example, if a track is mixed too loud, a music service may further process the track on upload or playback. Mastering to a specified loudness target before uploading to a music streaming service ensures that a track plays back as intended.


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Use our How-To guides to learn more about the Music Mastering APIs.

How to understand Music Mastering Preview Metrics
Learn more about your original music file media format, loudness, and EQ using the Music Mastering Preview metrics.

How to specify the output file format of your music master
Learn how to change the output format of your music master.


Supported audio formats

AACAdvanced Audio Coding - .m4a .mp4 .3gp .m4b .aac
AIFF IFFAudio Interchange File Format - .aif .aiff .aifc
FLACFree Lossless Audio Codec - .flac
WAVWaveform Audio File Format - .wav

Source files

When choosing source files for mastering, use lossless or uncompressed files with the highest sample rate, bit depth, and bit rate. Tracks that are heavily compressed or limited, restrict the ability of the mastering process to create the best sounding track.

Output format

The Music Mastering API returns the same file format, bit rate, bit depth, and sample rate as the source file that you provided unless you specify a different file format. To learn more, see the How to specify the output file format of your music master guide.

Mastering preview

The Music Mastering Preview API gives music creators the option to try out different music mastering settings for free (subject to the fair use policy). From a single Music Mastering Preview API call, you can get up to five 30-second previews with your choice of mastering profile, loudness setting, and stereo image enhancement, output to AAC format. Select the starting point for your preview or use the default starting point of 45 seconds into the track. Music Mastering Previews give music creators the opportunity to listen and evaluate different mastering settings and determine which one best suits their music. After the music creator has evaluated the previews, they may choose to purchase a full master of their music track processed using their favorite mastering settings.

Mastering profiles

The Music Mastering API offers a range of profiles that help shape the frequencies in the music track to meet the desired sound of the music creator. To help the music creator decide which profiles and loudness values to use, you can select up to 5 different profiles with the Music Mastering Preview API in a single call. After the music creator has chosen the profile that best matches their sound, they can use the preferred settings to create a final release-ready music master.

The list provided below is for guidance only. Explore the possibilities using the music creator's own music style and preferences.

Profile ValueDescriptionSuggested Use
aTight dynamics and ample brightness in the upper frequencies.Pop
bTight dynamics, a solid low-end, and mid-frequency clarity for vocal emphasis.Club, EDM
cBig bass presence and tight dynamics.Hip Hop
dHeavy bass and sub-bass presence.Hip Hop
eBig bass and sub-bass presence with additional openness in the mid and high frequencies.Hip Hop, Trap
fWide low-end processing with a light and ethereal tone.Lighter Electronic, EDM
gWide low-end processing with dark and moody tone.Darker Electronic, EDM
hWide dynamics and ample openness in the mids and highs to allow for a wide spectrum of sound.Electronic, EDM
iTight dynamics, and a well rounded, balanced tone.Pop, Rock, Country
jSmooth, tight dynamics, and a light lift in the upper frequencies.Rock, Country
kWide dynamics with a solid low and mid-frequency boost.Pop
lEmphasis on the mid-frequencies to highlight vocals.Vocal
mLight touch with ample mid-frequency clarity to let acoustic instruments shine in the mix.Folk, Acoustic
nWide dynamics, and warm full tones for orchestral instruments.Classical


Don't see a profile that works for your audio? Reach out to to make a suggestion for future preset development.

Mastering profile intensity

The intensity parameter controls how much of the tonal adjustment (dynamic equalization) is applied. Music creators can select a value from 0 to 100 percent. A value of 0 applies no tonal adjustment, while a value of 100 applies the full amount. If an intensity is not specified, the default value of 100 is applied.


The loudness parameter controls the target loudness in LUFS (Loudness Units relative to Full Scale). The default is a target level of -14 LUFS, and the level can be adjusted to meet a streaming provider's requirements. Check out the recommended target loudness for each streaming provider in the list below.

Loudness ProfileLoudness (LUFS)Maximum True Peak (dBTP)

To learn more, see the Loudness audio guide.

Stereo image enhancement

When enabled, stereo image enhancement intelligently analyzes the music track and applies the appropriate amount of stereo image widening or tightening to the low, mid, and high-frequency bands to achieve better stereo balance. This feature is enabled by the outputs[].master.stereo_image.enable parameter. This parameter is disabled by default so the existing processing calls are unaffected. This feature fixes stereo image balance problems that can be identified using the stereo image width metrics returned during a music mastering preview.