Free Online Mastering, in Your Browser.
Real metering. True-peak safe.
Deterministic DSP, not a black-box model — the same input always gives the same output, and you can see and change every stage. Real LUFS and true-peak metering for Spotify, Apple Music, YouTube, club, broadcast and vinyl. No card, no subscription.
Hear it on your own track
Drop a file and listen. Three independent compressors work on lows, mids and highs separately — and you can watch each one as it happens. Nothing is uploaded; the processing runs on your device.
Mastering for every platform — Spotify, Apple Music, YouTube and more
Each platform normalises loudness differently. Quantara normalises toward the reference for your destination and holds a true-peak-safe ceiling — club, broadcast and vinyl targets included.
Genre presets: mastering tuned for 33 styles
Pop, Hip-Hop, EDM, Metal, Jazz, Afrobeats, K-Pop, Cinematic and more — each preset is a genre-aware starting point. You dial in every stage from there; mastering always responds to the track in front of you, not just a label.
Created with AI. Finished with Quantara.
Generators give you a mix. Mastering is what makes it sit alongside commercial releases — consistent loudness, true-peak safety for streaming codecs, and the final tonal balance.
Export from your generator, drop the file here, and hear every stage of the chain before you commit. The processing is deterministic DSP — not another model guessing at your track.
What a professional mastering chain gives you
Built by engineers, for producers.
15-Stage Mastering Chain
HPF, sub shelf, low-mid cleanup, presence, air EQ, noise and hiss reduction, a 31-band graphic EQ, harmonic saturation, glue compression, parallel compression, independent mid/side dynamics, true mid/side stereo width, side-channel EQ and a true-peak limiter. Every stage adjustable in real time, with A/B bypass.
all major Loudness Targets
Normalised references for Spotify, Apple Music, YouTube, Tidal, Amazon, Deezer and iTunes; loud creative presets for Club, Beatport and SoundCloud; plus specialised targets: EBU R128 broadcast and vinyl.
33 Genre Starting Points
7 categories: Pop & Mainstream, Urban, Electronic, Rock & Metal, Latin & World, Acoustic & Classical, and Other. Each is a sensible starting point for the genre — then you adjust to the actual track.
Real-time Metering
Live spectrum, BS.1770 loudness (LUFS), true-peak detection, waveform with click-to-seek, and gain-reduction read straight from the compressor and limiter — not estimated.
Reference Matching
Upload any commercial track as a reference and match its tonal balance, dynamics and loudness. Available on Pro and above.
Multi-Format Export
WAV 16-bit (CD quality), WAV 24-bit (studio), WAV 32-bit float (Label plan). True-peak limited at −1 dBTP, measured with 8× oversampling.
REST API Access
Label plan includes full API access with personal API keys. Automate your mastering pipeline, integrate with your DAW workflow or CI/CD system.
How online mastering works — three steps, full control
No plugin to install. Works entirely in your browser.
Upload your mix
Drag and drop any WAV, FLAC, MP3, M4A, AIFF or OGG file up to 500MB. Audio processing happens in your browser — your file is decoded and processed on your own device, and never uploaded for mastering.
Choose your target & dial in your sound
Pick a loudness target and a genre starting point, then fine-tune all 15 stages in real time. A/B bypass lets you hear exactly what each move does.
Export, normalised and true-peak safe
Click Export. Quantara measures the integrated loudness (BS.1770), normalises toward your target, and applies a true-peak limiter at your ceiling (default −1 dBTP). Free accounts get 3 exports/month; Pro and above are unlimited.
Free mastering plans — start free, scale when you're ready
No hidden fees. Cancel anytime. Annual plans save 2 months.
Free plan with 3 exports/month, plus Pro, Studio and Label tiers.
Open Studio to see current plans →Transparent mastering you can hear and measure
No invented numbers, no fake quotes. Judge it the way an engineer would — with your ears and real meters.
Hear every decision
A fully adjustable 15-stage chain with instant A/B bypass, so you can hear exactly what each stage does to your track. Everything runs in your browser — your audio is never uploaded.
Measured, not guessed
Loudness is metered to the BS.1770 standard, peaks are read as true-peak, and gain reduction comes straight from the compressor and limiter — not estimated from a spectrum.
Honest by design
Exports normalise toward each platform's loudness reference and hold a true-peak-safe ceiling, instead of crushing everything to a loudness-war number. For high-stakes releases, it complements critical listening rather than replacing your ears.