ONDIS is a browser-based audio mastering tool developed by Modulink, designed specifically for tracks generated by artificial intelligence music platforms such as Suno, Udio, ElevenLabs, Stable Audio, and Riffusion. The application processes audio entirely within the user's browser using the Web Audio API, meaning no audio data is transmitted to external servers. This approach ensures that unreleased or private tracks remain on the user's device throughout the mastering workflow. The tool provides a three-step workflow. Users first export a track from their AI music generator and drag the file into the browser interface. Supported file formats include MP3, WAV, and FLAC, though FLAC decoding depends on browser compatibility (working in Chrome and Edge). In the second step, users select a preset such as Club or Warm Analog, or they can upload a reference track to automatically adjust the EQ tilt toward that track's tonal balance. Manual fine-tuning controls are also available, including three-band shaping with a dedicated subsonic filter, true mid/side widening for stereo enhancement, and loudness optimization targeting streaming levels (e.g., -14 LUFS) or club loudness. A transparent limiter manages peak levels. Users can instantly A/B compare the raw upload with the processed master while playback continues. In the third step, the user renders a clean offline master and downloads it as either WAV or MP3. Key features include in-browser mastering with all presets and controls, true LUFS metering, 24-bit and high-bitrate export, multi-band reference matching, saved presets and processing chains, batch mastering for consistent album loudness, and stem-aware processing. During the beta phase, all premium manual fine-tune controls are temporarily unlocked for testing. The application is intended for musicians and producers who generate audio with AI tools and need a quick, private way to polish the final mix for distribution or personal use.