AI mastering online: hear it free. Pay only if you keep it.
Drop a track. No signup, no install. One master €2.99.
New First month free on Starter – then 4.90 EUR/moThe mastering tool is loading…
Open the mastering tool →ZERRRO Engine is an AI mastering tool that runs in your browser. Upload a premaster and it checks bit depth, true peak, clipping and loudness for free. Then pick a genre, a character and a loudness target while your track plays in a loop, drag the EQ dots or type what you want in plain words, and hear every change immediately. Render the master, A/B it against your mix at matched loudness and decide. Download the 24-bit WAV and MP3 for one credit, or subscribe if you master often.
Shape it live. Make it loud.
Pay only if you love it.
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Format, true peak, clipping, loudness and your BPM — checked in seconds, with a plain verdict and four quick notes on where your mix stands.
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Your track plays in a loop while you pick a genre — the target adapts to what your mix already has. Or hit ZERRRO Magic and it picks genre, strength and character for you.
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Drag the EQ dots, type a wish like “brighter, less mud”, choose a character and a loudness. You hear every change the moment you make it.
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One click renders the master. A/B it against your original at the same level, read the real, measured numbers — then decide. Not there yet? Change anything and render again, free.
What producers say
Straight from the “How does it sound?” form inside the tool.
“I have some experience with similar tools and I have to say that I really liked this one. The editing options together with the AI model and the user-friendly environment are a great combination with interesting results. Good job guys. I will definitely use it again.”
“Pay as you go option is Class!”
“Wow. This actually is insanely good”
“Amazing mastering. I spent a long time trying to master my track myself, but only the zerrro engine gave me a result I was truly happy with. Really powerful tool.”
Rated “Great”
“Nice everything”
“I really like the depth you brought to my track!”
“perfect. i love the flexibility of this tool. Haven’t seen anything like this”
“Loving the mastering function, especially the different sub genres that offer different dynamics. […] This is genuinely one of the better AI mastering tools I’ve used.”
Rated “Great”
“I love the flexibility and being able to describe the sound I want. […] Overall the AI is great.”
“Perfect!”
“love that you can shape your own sound on the go”
Rated “Great”
“Very nice”
Preview free.
Pay only for the download.
- The master you just heard, full length
- 24-bit WAV + 320 kbps MP3
- Download link right away and by email
- Every master included, WAV + MP3
- Cancel anytime
Honestly? We’re still in beta.
ZERRRO Engine is new and improving every week. It’s already producing great masters — but it’s not perfect yet, and you might hit a rough edge. That’s exactly why the preview is free: try it on a real track, and if it’s not right, you’ve lost nothing but a few minutes. If you tell us what didn’t work, we’ll fix it.
Questions producers ask
Is the AI mastering really free?
Mastering and listening are free. You hear the finished master in full, A/B it against your own mix at matched loudness and render it again as often as you like without paying anything. You pay only when you want the files: one credit costs €2,99 and unlocks that track completely.
What do I get when I unlock a master?
The master you heard, full length, as 24-bit WAV and 320 kbps MP3. True peak never goes above 0 dBTP, and streaming masters stop at −1 dBTP. The download link appears right away and is sent by email, and the files stay in My Masters for 12 months.
Which loudness should I pick?
For streaming, a master around −14 LUFS keeps its dynamics, because Spotify, Apple Music and YouTube normalise anyway. For the club, most house and tech house releases sit around −9 LUFS; dense techno goes louder. You pick the target in the tool and hear the difference before you decide.
How does it compare to LANDR or eMastered?
The main difference is the workflow: your track plays in a loop while you change genre, character, EQ dots and loudness, and you hear each change the moment you make it. You judge the result against your own mix at matched level and pay per track or per month, with no card needed for the preview.
How should I export my premaster?
Export a WAV at 24-bit, at your project’s sample rate, with about 3 to 6 dB of headroom and no limiter on the master bus. The free premaster check reads bit depth, sample rate, true peak, clipping and loudness before anything is processed and tells you in plain words whether the file is usable. Full export guide →
Do my credits expire?
Credits you bought outright never expire. Masters included in a monthly plan are available while the plan runs. Every track you have unlocked stays downloadable in My Masters for 12 months.
Your next release
deserves a real master.
Drop a track at the top of this page. Free, right now — decide after.
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