Terms, privacy & licenses
In short: NetherFlow is a free, open-source music player made by Volodya.rua (GNU GPL v3). It doesn't host any music, videos or lyrics: it finds them on other services (YouTube and YouTube Music, Audius, Apple's iTunes catalog, LRCLIB, NetEase Cloud Music and Kugou) and shows them to you directly from those services. If you choose to save a song for offline listening, the app downloads it from YouTube and keeps it inside the app, on your device only. NetherFlow has no accounts, no ads of its own and no tracking of what you do, and the developer keeps none of your data: NetherFlow's own relay passes on only encrypted messages it can't read and keeps no logs. The one thing it counts is installs (Count me once, below), with nothing about you. NetherFlow is a neutral tool: it doesn't host, store, sell or make money from any content, and it doesn't support, encourage or take part in piracy or any unlawful use. What you choose to do with it is your own responsibility.
Terms of Use
1. Who we are
NetherFlow ("the app") is developed and published by Volodya.rua ("the developer", "we", "us"). By installing, opening or using the app, you agree to these Terms of Use and to the Privacy Policy below. If you don't agree, don't use the app and uninstall it.
NetherFlow is free and open-source software: its source code is public and licensed under the GNU General Public License version 3, with a few additional terms (see section 10). These terms are about using the app and the services it connects to; they don't limit what that license lets you do with the code.
You may use NetherFlow only if you can form a binding agreement with the developer and are not barred from doing so by law. NetherFlow is not directed to children: you must be at least 13, or the minimum age for digital consent where you live if that is higher (for example 16 in parts of the European Union). If you are under 18, use NetherFlow only with a parent or guardian's involvement. The app asks you to accept these terms and the Privacy Policy before you use it, and again when they change; that acceptance is how you agree to them.
2. What NetherFlow does
NetherFlow is a player interface. It searches public catalogs, plays songs from YouTube through FlowStream (NetherFlow's own engine), and shows lyrics published by third-party lyrics services. It also plays podcasts, from each show's own feed and host, and audiobooks recorded by LibriVox's volunteers, from the Internet Archive. LibriVox's recordings are in the public domain in the United States; some of the books may still be under copyright in other countries (where copyright lasts longer after an author's death), so check the law where you live before you listen to or save one. It also plays live concert recordings from the Internet Archive's Live Music Archive, which bands allow the Archive to share for non-commercial listening; each recording stays its band's, under the Archive's terms. NetherFlow does not host, upload, sell or distribute any music, video, podcast, audiobook or lyrics, and the developer makes no money from any of it. NetherFlow does not support, encourage or take part in piracy or any other unlawful use: it is a neutral tool, and what you choose to do with it is your responsibility alone. Content is streamed directly from those third parties to your device; the only copies the app keeps are the songs, episodes and chapters you choose to save for offline listening (section 6), which stay on your device. All content belongs to its respective owners (artists, labels, publishers, podcasters, readers and the services themselves). Podcasts and audiobooks are their makers' own: the developer doesn't choose, check or endorse what they say.
3. Content is for personal, non-commercial use only
The music, videos, podcasts, audiobooks, lyrics and artwork you reach through NetherFlow belong to their owners, not to the developer: use them only for your own personal, non-commercial listening. Apart from saving songs, episodes and chapters for your own offline listening inside the app and making story clips (both in section 6), you must not use NetherFlow to download, record, copy, redistribute, broadcast, publicly perform, or commercially exploit any content, or to break any law that applies to you.
4. Third-party services and their terms
NetherFlow relies on independent services that have their own terms, which also apply to you when the app uses them, including YouTube's Terms of Service, Google's Terms of Service, Apple's Media Services terms, Spotify's Terms of Use (when you import from it), Audius's Terms of Use, LRCLIB, NetEase Cloud Music, Kugou, the AMLL lyrics database and LyricFind (whose lyrics YouTube Music shows), the Internet Archive's Terms of Use, and each podcast's own terms, set by its publisher. You are responsible for using NetherFlow in a way that respects those terms and the laws of your country.
The developer doesn't control these services. They may change, limit or stop working at any time, and NetherFlow may stop working with them as a result. Songs, videos, lyrics and timing may be missing, inaccurate or out of sync.
5. How NetherFlow plays, and advertising
NetherFlow plays audio, and any music video, straight from each service's own servers to your device, through its own engine (FlowStream), and it shows no advertising of its own. It does not add, block, skip or alter advertising, and it keeps any video out of view while the lyrics are shown. Content is streamed directly from third parties to your device; the only copies NetherFlow keeps are the ones you choose to save for offline listening (section 6). If you choose to play on a TV or speaker on your network, that device fetches the song directly from the same service.
6. Saving for offline listening, and story clips
NetherFlow can save a song you choose, with its cover and, if you choose, its lyrics, so you can listen without an internet connection. To do this it downloads the song's audio from its YouTube upload with FlowStream, NetherFlow's own engine, just as YouTube serves it (nothing is re-recorded or re-encoded); or, when the artist's own upload of the song is on Audius, the file Audius serves for it. Saved songs stay inside the app on your device, for your own personal listening only: you must not extract, copy, share, sell or distribute them.
YouTube's Terms of Service don't allow downloading content unless YouTube itself shows a download button for it, so saving songs this way breaks YouTube's terms. It may also not be permitted by the rights holders or by copyright law where you live. Whether to use it is your decision and your responsibility. Only save content you are allowed to keep a copy of, and delete saved songs if you are asked to or are no longer allowed to keep them. The developer provides no content and never receives the songs you save.
A podcast episode or an audiobook's chapter is saved as the file its host publishes for listeners to download, not through FlowStream: the podcast's own host, or the Internet Archive for LibriVox's recordings, which are in the public domain in the United States (see section 2). Saved episodes and chapters stay inside the app on your device too; a podcast stays its publisher's, under its own terms.
A live concert's song can be saved only when the Internet Archive offers that show for download. Shows the Archive keeps for streaming only are never saved, and a recording you save stays its band's, for your own personal listening.
"Make a story" creates a short video (about 15 seconds of the song, with its cover and lyrics) for you to share. Whether to post it is your decision and your responsibility: the song, cover and lyrics belong to their owners, and the platform you post to (for example Instagram) applies its own music and copyright rules and may mute or remove it.
Sing's AI karaoke separates a song's voice from its music on your device, for your own listening while it plays. The separated parts are never saved, shared or used in story clips.
7. No affiliation; trademarks
NetherFlow is an independent project. It is not affiliated with, funded by, authorized by, endorsed by or sponsored by YouTube, Google, Apple, Spotify, Audius, LRCLIB, NetEase, Kugou, the AMLL lyrics database, LyricFind, the Internet Archive and its Live Music Archive, LibriVox, AutoEQ, Discord, any podcast or its publisher, or any artist, label or publisher, or any of their affiliates or subsidiaries. YouTube is a trademark of Google LLC; iTunes and Apple Music are trademarks of Apple Inc.; all other names, logos, album artwork and trademarks belong to their respective owners and are shown only to identify the content you chose to play.
8. Reporting content; copyright
NetherFlow hosts no music, video or lyrics; it shows content from the services in section 4, and the little it carries for you (an encrypted shared playlist on the relay) it cannot read. If you own rights in content and believe it is being made available through NetherFlow in a way that infringes them, tell the developer (see Grievances and Contact) with: the content concerned and where it appears in the app; enough detail to find it; your contact details; a statement that you believe in good faith the use is not authorised; a statement, under penalty of perjury where that applies, that your notice is accurate and that you are the rights owner or authorised to act for them; and your signature (electronic is fine).
The developer reviews every notice in good faith and, where appropriate, removes or blocks the content or source in the app and may remove the content from the relay. The developer will, where appropriate, limit or end access for anyone who repeatedly makes infringing content available. If content you shared was removed and you believe that was a mistake, you may send a counter-notice with the same kind of detail, and the developer will consider it in good faith.
9. Acceptable use
You must not use the app for anything unlawful, or to send automated or excessive requests to any service. A playlist you edit together, and its name, can be seen and changed by everyone who has its link: don't use one to pass on anything unlawful, or anyone's private information, and share its link only with people you trust. If you publish a changed version of NetherFlow, its license requires you to share it under the same license with its source code, to keep the credit "NetherFlow by Volodya.rua" on its credits screen, and to give it a name and icon of its own, so nobody mistakes it for the original (see section 10). Remember that you, not the developer, are responsible for what your version does.
10. Open source and intellectual property
NetherFlow's source code, design and artwork are © 2026 Volodya.rua and licensed under the GNU General Public License version 3, with the additional terms in NOTICE (see Licenses & credits): anyone may use, study, copy, change and share them, as long as what they pass on stays under the same license with its source code, keeps the credit "NetherFlow by Volodya.rua", and uses a name and logo of its own. The name NetherFlow, its logo and the name Volodya.rua are not licensed to anyone. NetherFlow 1.3.1 and earlier were released under the MIT License, and copies of those keep it. The license covers NetherFlow itself only: it gives no rights to the music, videos, podcasts, recordings, lyrics or artwork of others, or to anyone's trademarks. The open-source components NetherFlow includes keep their own licenses (see Licenses & credits).
11. No warranty
The app is provided "as is" and "as available", without warranties of any kind, express or implied, including fitness for a particular purpose, accuracy, availability and non-infringement, to the maximum extent permitted by law.
Headphone correction follows measurements published for each headphone model (by AutoEQ), which may not match your own pair; charts, playlists and suggestions come from third parties and may be wrong or unsuitable; a playlist edited together can be changed by anyone with its link, and the relays keeping it may lose it (your own copy stays on your device). Keep the volume at a safe level, especially with the volume booster, the equalizer or headphone correction on.
Flashing light. Some of NetherFlow's looks flash and move quickly, including Extreme lyrics' Strobe look and backgrounds and screen edges that pulse with the beat. If you have photosensitive epilepsy or are sensitive to flashing light, keep Extreme lyrics off and choose calmer looks, and stop using the app straight away if you feel unwell.
In a car. Don't look at or handle your phone while you drive. Control the music with Android Auto, your car's own controls or your voice, and follow the road laws where you are. NetherFlow can start or resume music by itself when your car connects; you can turn that off in Settings › Play when connected (and, if you switched it on, Settings › Start by itself in the car).
12. Limitation of liability
To the maximum extent permitted by law, the developer is not liable for any indirect, incidental, special, consequential, exemplary or punitive damages, or for any loss of or damage to data, profits, goodwill, devices or use, however caused and on any theory of liability, arising out of or related to NetherFlow, any third-party service, terms or content, or your inability to use any of them, even if the developer was told such damage was possible. Because NetherFlow is free and the developer receives nothing from you, the developer's total liability for all claims together is limited to the greater of what you paid for NetherFlow (zero) and the lowest amount the mandatory law where you live allows. Some places don't allow some of these limits, so some may not apply to you.
13. Your responsibility
To the extent permitted by law, you agree to defend, indemnify and hold harmless the developer from and against any claims, demands, damages, losses and costs (including reasonable legal costs) arising out of or related to your use of NetherFlow, your content, your breach of these terms or of any third party's terms, or your breach of any law or of anyone's rights. This does not cover a loss to the extent the law does not allow it to be shifted to you.
14. Your content
Some features let you create or share content: playlists you make or edit together, "Mix with a friend" links, the names and reactions you use in Listen together, and the anonymous song matches your app may add to NetherFlow's shared match cache. You keep whatever rights you have in what you create. You are responsible for it, and you confirm that you have the right to share it and that it is not unlawful, infringing, or someone else's private information. Only to run the feature you chose, you give the developer a limited, non-exclusive, worldwide, royalty-free licence to transmit, store and display that content as the feature needs (for example, to carry an encrypted shared playlist on the relay so people with its link can open it). That licence ends when the content is deleted or the feature stops, except for copies others already received. The developer may remove content, or limit or end a feature, where it is unlawful, infringes someone's rights, or breaks these terms.
15. Assumption of risk; release
NetherFlow is a tool for reaching content and services that other people provide and control. You use it, and every feature in it, at your own risk and discretion. To the maximum extent permitted by law, you release the developer from any claim arising out of content you reach, save, create or share through NetherFlow, out of any third party's service, terms or content, and out of your own choice to use a feature that a third party's terms may not permit (such as saving for offline listening). Nothing here takes away a right you cannot give up under the mandatory law where you live.
16. Disputes
If you have a concern, please contact the developer first (see Grievances and Contact): nearly everything can be settled that way, without a formal dispute. To the fullest extent the law allows, you and the developer agree that any dispute will be brought only on an individual basis, and not as part of any class, consolidated or representative action, and you each give up any right to a jury trial. These terms are governed by the law of India and subject to its courts (section 20). None of this takes away any right you cannot give up under the mandatory consumer-protection law of the country where you live, including any right to bring a claim in your own country's courts or before a local consumer body.
17. Grievances and complaints
The developer, Volodya.rua, is also the grievance officer for NetherFlow. If you have a complaint about content, a possible rights infringement, privacy, or these terms, email volodya.rua@gmail.com with the details. The developer will acknowledge your complaint within 24 hours and aim to resolve it within 15 days, or sooner where the law requires. The developer will act on a valid order from a court or an authorised government authority within the time the law requires, and will take down or disable content or a source where it is lawful and appropriate to do so.
18. General
These terms, with the Privacy Policy and the licence (NOTICE), are the entire agreement between you and the developer about using NetherFlow, and replace anything said before. If any part is found unenforceable, the rest stays in effect and that part is narrowed only as much as needed. The developer not enforcing a term at some point is not a waiver of it. You may not transfer your rights under these terms; the developer may transfer its rights and obligations, for example if the project passes to a new maintainer, without reducing your rights. The developer is not responsible for delays or failures caused by things beyond its reasonable control. Terms that by their nature should continue (on content ownership, disclaimers, no warranty, liability, release, indemnity, disputes and these general terms) survive after you stop using NetherFlow. These terms create no rights for anyone other than you and the developer.
19. Changes and ending
We may update these terms; the app will show the new version and ask you to accept it again. We may change, suspend or discontinue the app at any time. You can stop using it at any time by uninstalling it.
Official releases are published by the developer on NetherFlow's GitHub page. Copies from anywhere else may have been changed by someone else: the developer isn't responsible for them.
20. Governing law
These terms are governed by the laws of India, without regard to conflict-of-law rules, and the courts of India have jurisdiction over any dispute about them. Nothing in these terms limits rights you have under mandatory consumer-protection laws of the country where you live, including any right to bring a claim in your own country's courts. If any part of these terms is found unenforceable, the rest stays in effect.
21. Contact
Questions, copyright notices or privacy requests: Volodya.rua, the developer of NetherFlow. Email volodya.rua@gmail.com, or message @volodya.rua on Instagram.
Privacy Policy
Summary
NetherFlow has no accounts, no ads of its own and no tracking of what you do, and since its source code is public, anyone can check that. The developer doesn't collect or sell any personal data, and keeps none: NetherFlow's own relay (below) only passes on, and for shared playlists keeps, encrypted messages it can't read, with no logs. The only thing it counts is installs: each install adds 1 to a public number, once, with nothing about you, unless you untick Count me once (see the relay, below). To work, the app also talks directly from your device to the third-party services listed below, which receive the information described there under their own privacy policies.
Stored only on your device
- Your settings: mood, background and its quality (or the quality the app picked for your device), lyric animation (and Extreme lyrics, their look, emoji and music video), font, size and alignment, timeline and beat styles, the island and its glow, volume, repeat, equalizer and loudness.
- Lyric-sync adjustments you made for individual songs.
- Your search history: recent searches and recently played songs (you can clear it in the search screen).
- Your library: liked songs and playlists (and playlists you import).
- When you import everything from Spotify, NetherFlow first tells you which parts of the file it uses, and goes ahead only if you agree. The data file you pick (my_spotify_data.zip, or the files in it) is read on your device and never uploaded or kept. Only YourLibrary.json and your Playlist files are opened; the others (your listening history, searches, payment details, location, voice input, messages, Spotify's inferences about you and the rest) are never loaded, apart from their names in the file's list. What it finds joins your library, looked up as described below.
- Your listening stats: time listened by day, hour, part of the day (morning, afternoon, evening, late night), song, artist and genre (Library › Your stats).
- Autoplay's memory: the songs you've heard lately (so they aren't picked again soon) and how much you like each artist it picks, from what you skip, play through or like.
- Songs, podcast episodes and audiobook chapters you saved for offline listening, with their covers and, if you chose, their lyrics (you can remove them in the Library).
- The first moments of the last 100 songs you played (about 256 KB each), kept on your device so they start instantly, and never synced. Turn it off or clear it in Settings › Instant start.
- Album covers and playlist pictures you've seen (the newest 4,000), kept on your device so they show at once next time, and never synced.
- The list you were playing and, with Shuffle on, its shuffled order and which of its songs you've heard, so Next and Shuffle carry on after NetherFlow is closed. Kept on your device only, never synced.
- The pictures you chose for the Pictures background, made smaller to fit a screen (at most 2,560 pixels across), and how they're dimmed, blurred and changed. Kept on your device only: never synced or uploaded, and never put in story clips, Listen together or anything you share. Remove them all where you chose them (Your pictures › Clear).
- AI karaoke's files (about 67 MB: the ONNX Runtime engine and the Spleeter voice-and-music model): built into the Windows app; on Android, only if you chose Get AI karaoke (remove them in Settings › AI karaoke › Remove). With Sing's AI karaoke on, the song playing is read once more from where it plays (its service, or your saved copy) and separated into voice and music on your device, in memory only: none of it is kept or sent anywhere. (There's no AI karaoke on Linux.)
- On Windows, the voice pack (about 107 MB, or 126 MB on a computer whose graphics card it can use: the Whisper speech recognizer and the ONNX Runtime engine), only if you chose Get the voice pack; remove it in Settings › Voice pack › Remove. With it, what you say is turned into words on your computer (partly on its graphics card, where it can) and never sent anywhere. A newer version of the pack is downloaded only if you agree. (There's no voice control on Linux.)
- The artists you follow (kept on your device). For each, NetherFlow checks Apple for new releases about twice a day (see the Apple row below); on a computer, if you allow it, it shows a system notification when there is a new release, and on a phone an in-app message.
- On Android, a light copy of your library for the car (Android Auto): your liked songs, recently played and playlists, each song as its id, title and artist (up to 500 per list), kept in the app's private files so the car can show them while the app is closed. NetherFlow hands this only to Android's media service, which shows the list to Android Auto and Google's assistant (checked by their app signature) and to the system media controls; any other app gets only the play controls, not the list. To start or resume music in the car, NetherFlow also checks, on the phone only, whether Android Auto is connected and which sound output is in use (Bluetooth, a cable or USB); nothing of that is sent anywhere.
- The Bluetooth devices you told NetherFlow are, or aren't, your car, by the name each one reports, so it knows when you're in the car. Kept on this phone only, never synced or sent; forget them any time in Settings › Forget my cars.
- Podcasts you follow, audiobooks you're listening to, where you left each episode and chapter, and your listening speed for them.
- The headphones you picked for headphone correction (Equalizer › Headphones), and its settings.
- That you accepted these terms, and which version; whether Count me once was ticked, and whether this install has been counted (so it's never counted twice).
- A YouTube "visitor" id (visitorData) that YouTube gives on your first search, kept so playback keeps working; it isn't an account and isn't tied to you.
- Phone ↔ PC sync copies your library, history and stats directly between your own devices on your local network, encrypted with a key made from the code shown (as 12 numbers, or as a QR code to scan): it never goes through anyone else's server. Listen together sends only what the session needs (the song, where it's at, names, reactions), encrypted, through NetherFlow's relay (or, if it can't be reached, a public one).
- Sharing a playlist (Library › Share) makes a link and a QR code that carry the playlist's name and its songs. Usually it's a short link: NetherFlow encrypts the playlist on your device with a random key, keeps the encrypted copy on its relay (below), and puts the key only in the link, after the #, which browsers never send. The relay can't read it, and deletes it a year after the link was last opened. If the relay can't be reached, the playlist goes inside a longer link instead, and nothing is uploaded. Either way, anyone you give the link to can see what's in it. Opening the link shows a page on GitHub Pages (github.io), which, like any website, receives the opener's IP address; the part of the link holding the songs, or their key, is not sent to it; for a short link, the page fetches the encrypted copy from the relay and unlocks it in the opener's browser. That page looks the songs up at Apple and shows their covers from Apple and YouTube.
- "Mix with a friend" (Library) makes a link that carries your top songs (up to 40: their titles, artists and ids) and the name you type, inside the link itself, like a shared playlist. Nothing is uploaded, but the link shows your listening taste to anyone you send it to, so share it only with people you want to see that.
- A playlist you edit together with others ("Edit together") is the exception: so that everyone with its link can open and change it, it is kept on the relays described below (NetherFlow's own, and for now the public ones as a backup), encrypted on your device with a key made from the code in its link. Anyone who has the link can see and change the playlist, so share it only with people you trust; "Stop editing together" keeps your own copy and stops sending changes; the copy on the relays stays for the others who have the link, until the relays drop it (NetherFlow's relay deletes it 12 months after its last change). Opening such a link on its web page reads it from those relays too.
This stays on your device and is never sent to the developer. Uninstalling the app (or clearing its data) deletes it.
Shared with third-party services when you use the app
| Service | When | What it receives |
|---|---|---|
| Apple iTunes Search API & Apple image servers | When you search (songs, and podcasts in Library › Podcasts), to show album and podcast artwork and 30-second previews, to fetch Apple's top podcasts for your country, and for Explore's "New from artists you play" (the names of the artists you play and like most, looked up there), and, if you follow artists, about twice a day to check each followed artist's id for new releases; and, when you import everything from Spotify, the names of the artists and podcasts you follow there (with each podcast's publisher), to find them; and, after an import, the title and artist of each song that still has no cover, one every few seconds (on a phone only on Wi-Fi), to find its cover | Your search text, or those songs', artists', podcasts' or publishers' names, your country, your IP address and basic device/browser information. Apple Privacy Policy |
| YouTube (Google) | To find and play the songs you choose, to save the ones you choose for offline listening, to read a playlist or album you import from a YouTube or YouTube Music link (and, if 'Kept in sync' is on, again about once a day to add its new songs), and (desktop, with Extreme lyrics' music video on) to find and play the song's official music video behind the lyrics, muted; and, with Sing's AI karaoke on, to read the song once more and separate its voice from the music on your device. NetherFlow fetches these streams from YouTube's own servers (youtube.com and googlevideo.com) with its own engine, FlowStream, instead of through YouTube's embedded player | The song's title and artist (or the link of a playlist or album you import), your IP address and device information. These requests carry a YouTube "visitor" id (not an account, not tied to you) so playback keeps working. Google Privacy Policy |
| YouTube Music (Google) | As you type a search (suggestions), when you search, to fetch the lyrics of the song playing (provided by LyricFind), for Explore (your country's charts, new albums, moods and genres, and their playlists), to make the mixes made for you (Your mix, Discover, Weekly picks and Today's mix), and, with Autoplay on, to find songs like the one playing when your list ends (its radio) | What you type in the search, the ID of the video playing, your country, for the mixes the IDs of a few songs you like or play most, your IP address and basic device information. Google Privacy Policy |
| Each podcast's own host (and the measurement services its links may pass through, such as Podtrac) | When you open a show, play an episode, or save one for offline listening. On the computer, the feed and saved episodes come through NetherFlow's own built-in server, on your computer, as most hosts don't let a page read them directly | Your IP address and basic device information, and which episode you play or save; podcast hosts commonly count downloads this way. Each host has its own privacy policy, usually linked from the show's website |
| Internet Archive (archive.org) | When you open Library › Audiobooks or Live concerts, search for a book, a band or a show, open one, or play or save a chapter or a song (LibriVox's recordings, and concert recordings from the Archive's Live Music Archive), and when a search finds an artist, their name, to look for their live concerts | Your search text or the artist's name, which book, show, chapter or song, your IP address and basic device information. Internet Archive Terms of Use and Privacy Policy |
| Audius | When a song plays or is saved, to look for the artist's own upload of it there, and to play or save that upload | The song's title and artist, and your IP address. Audius Privacy Policy |
| LRCLIB | To fetch lyrics | The song's title, artist and length, and your IP address. lrclib.net |
| NetEase Cloud Music | To fetch word-by-word lyric timing | The song's title, artist and length, and your IP address. music.163.com |
| Kugou | To fetch word-by-word lyric timing | The song's title, first artist and length, and your IP address. kugou.com |
| AMLL lyrics database (on GitHub, raw.githubusercontent.com) | When word-by-word lyrics are on, to fetch the open (CC0) word-by-word lyrics of the song playing | Which lyric entry (it encodes the song's id), and your IP address. GitHub Privacy Statement |
| GitHub (Microsoft) | To look for a newer NetherFlow, about once a day and when you open Settings, and to tell you when one is out. On NetherFlow's own Android app this daily check runs in the background even when the app is closed, so it can show a notification; the portable and .deb desktop copies, which can't update themselves, also make the daily check. You can turn these update notifications off in Settings › Update notifications. When you choose to update, to download it (the Windows installer and NetherFlow's own Android app; not an app store's). On Android, when you choose Get AI karaoke, to download its files once (about 67 MB), checked against their known fingerprints (the Windows app has them built in). And when you open Equalizer › Headphones, the list of headphones and, for the ones you pick, their correction (AutoEQ's published results, from raw.githubusercontent.com) | Your IP address and basic device information. GitHub Privacy Statement |
| Spotify, Apple Music | When you import a playlist, an album or a song from its link (pasted, scanned from a QR code, or shared to NetherFlow), or everything from Spotify, and, if 'Kept in sync' is on, about once a day after that to add a playlist's new songs: to read that public page and, for a long playlist, the rest of its songs from the service's own web player; for everything from Spotify, your saved albums, one at a time and slowly (a Spotify short link, spotify.link, first goes through Branch, the link service Spotify uses for them) | The link you pasted, scanned or shared (for everything from Spotify, each saved album's link), and your IP address. Spotify's privacy policy, Apple's, Branch's |
| Spotify's image server (i.scdn.co) | When a song from Spotify isn't matched yet (in a playlist you imported, or a Spotify song link you scanned, pasted or shared), to show its album cover (kept only on your device, like other covers you've seen, and never passed on; a shared or edit-together playlist carries the song without the cover) | Your IP address and basic device information. Spotify's privacy policy |
| NetherFlow's relay (run by the developer on Cloudflare's network) | During Listen together: to pass the session's messages between the people in it. For a playlist edited together: to keep its latest copy and pass its changes between the people who have its link. For a short share link: to keep the shared playlist and hand it to whoever opens the link | Messages encrypted on your device with a key made from the session's or the playlist link's code (the song, where it's at, names, reactions; or the playlist's name and songs), so the relay passes and keeps them scrambled: the developer can't read them. It keeps no logs and stores no IP addresses. It keeps nothing from Listen together. It keeps a playlist edited together as its latest encrypted copy, deleted 12 months after its last change, and a short share link's playlist, encrypted with a random key that exists only in the link, deleted a year after the link was last opened. Working out a session's or a link's code from what it sees would take years of computing; anyone you give a code or a playlist's link to can see what's sent. Count me once: when you accept these terms, a box called Count me once is ticked to start with in NetherFlow's own releases and in any installed copy on a computer (a copy of the Android app built by anyone else starts unticked, and a copy run from the source code never counts). If it's ticked when you agree, the app sends the relay one empty message, once for this install, and the relay adds 1 to a single public number, the install count on NetherFlow's GitHub page (shown there through shields.io, which fetches only the number). The relay keeps that number and nothing else: no ID, no time, no details of your device. Like any web request, the message carries your IP address and the standard details your device's web engine adds; the relay uses only the address, held in its memory while it runs to stop one address sending many counts, and never writes it down. Untick the box to skip it, or count later in Settings › Privacy (called Install count in the Glass theme). Nothing links the number to you, so a count already added can't be found or taken back; reinstalling, clearing NetherFlow's data, or a count whose answer never came back may count again. Cloudflare, whose network it runs on, sees your IP address when you connect, under its own privacy policy, and its servers may be in any country. Cloudflare's privacy policy |
| Public MQTT relays (EMQX, HiveMQ, Eclipse Mosquitto), as a backup | For Listen together, only when NetherFlow's relay can't be reached. For a playlist edited together, to keep it in step for members on older versions of NetherFlow | Messages encrypted on your device with a key made from the session's or the playlist link's code (the song, where it's at, names, reactions; or the playlist's name and songs), so the relay passes and keeps them scrambled. A kept playlist stays there until it's replaced or the relay drops it. These relays, unlike NetherFlow's own, are public test servers that anyone can connect to, and they may delete anything at any time. They, and anyone else on them, see only scrambled messages: working out a session's code or a link's code from them would take years of computing. Anyone you give a code or a playlist's link to can see what's sent. The relay sees your IP address. EMQX, HiveMQ, Mosquitto |
| Your phone's speech service (Android; usually Google's) | Only when you tap the mic button or Drive mode's Speak, and only if your phone can't turn speech into words by itself: to turn the one sentence you say into words | A recording of that sentence (NetherFlow sends it none of your library), under the speech service's own privacy policy. NetherFlow doesn't choose the service or see where the recording goes; it gets back only the words, which it uses like a typed search. Google Privacy Policy |
| Microsoft's online speech service (Windows) | Only when you tap the mic button, and only if you've turned on Online speech recognition in Windows' own settings: to turn the one sentence you say into words. Otherwise Windows works the words out on your computer | A recording of that sentence (NetherFlow sends it none of your library), under Microsoft's privacy statement. NetherFlow gets back only the words. Microsoft Privacy Statement |
| Hugging Face (huggingface.co and its file servers) | Only on Windows, when you choose Get the voice pack: to download the speech recognizer once, checked against known fingerprints | Your IP address and basic device information. Hugging Face Privacy Policy |
| jsDelivr (cdn.jsdelivr.net) | Only on Windows, when you choose Get the voice pack: to download the ONNX Runtime engine once, checked against known fingerprints | Your IP address and basic device information. jsDelivr Privacy Policy |
| Discord (its app on your computer) | Only with Discord status on: to show the song you're playing on your Discord profile | The song's title, artist, album, cover link and progress, and a link to the song on YouTube (its Listen on YouTube button), sent to the Discord app on your computer, which shows them to your friends there. Discord's privacy policy |
| Your TV or speaker (on your own network: Wi-Fi or cable) | Only when you open Play on a TV or speaker: to ask the devices on your network which can play (NetherFlow keeps nothing it learns, including their names), and, when you pick one, to tell it what to play; for a Fire TV without NetherFlow open, to ask it to open NetherFlow | The song's address (YouTube's, Audius's, the podcast host's or the Internet Archive's), its title, artist, album and cover link, and that it comes from "NetherFlow on a phone" or "on a computer". The device then fetches the song and cover itself from those services, which see its IP address; its own software, from its maker, handles what it plays under that maker's privacy policy. Nothing goes through NetherFlow's servers. |
| Other devices on your Wi-Fi (NetherFlow on a TV) | Only on a TV, while NetherFlow is open there and "Let phones and computers on this Wi-Fi play here" is on (Settings): to announce itself on your network and answer devices that look for something to play on, and to take their play, pause and move requests. The TV shows which device is playing | They see the name "NetherFlow on" and the TV's model, and a random id that isn't tied to you. A song sent this way is fetched by the TV itself from its service (secure https addresses only) and isn't added to the TV's history, taste or mixes; its lyrics are looked up as for any song. |
Android permissions
- Internet: to search and play music.
- Notifications (optional): to show what's playing while the app is in the background, and, in NetherFlow's own app from GitHub, to tell you when a newer NetherFlow is out (turn that off in Settings › Update notifications). Music still plays if you say no.
- Foreground service (media playback): to keep playing when you switch apps or turn the screen off.
- Network state: to tell whether you're on Wi-Fi, so liked songs save themselves for offline only then.
- Microphone (optional, asked the first time you tap the mic button or Drive mode's Speak): to hear one spoken command or search after each tap. Android shows its microphone indicator while it listens. Where your phone can, the words are worked out on the phone; NetherFlow keeps no recording and gets back only the words.
- Display over other apps (optional, off until you switch it on from Settings › Start by itself in the car): only so NetherFlow can open itself in the background when Android Auto connects or the car asks for a song. It never draws anything over other apps.
- Keep awake: to keep the phone and its Wi-Fi awake while a song plays, so the music doesn't stop when the screen goes off.
- Vibration: used only by MobiVib, which is off unless you turn it on.
- Camera (optional, asked the first time you open one of its two scanners: Library › Import › Scan a QR code, or Settings › Sync with computer › Scan the code): to read a QR code. What it sees is read on your device and never kept or sent, and the camera turns off when the scanner closes. If you say no, you can still pick a picture of a code.
- Wi-Fi multicast (used on TVs only, while NetherFlow is open there and "Let phones and computers on this Wi-Fi play here" is on): so phones and computers on your Wi-Fi can find NetherFlow on the TV.
- Install apps (NetherFlow's own app from GitHub only, and only once you allow it): to install an update you chose to download.
NetherFlow uses the camera only while one of those two scanners is open, and reads a picture or a file only when you pick it yourself. It uses the microphone only for one sentence after you tap the mic button or Speak; on Windows too, where Windows' own microphone privacy switch decides whether it may. The one exception is Hey NetherFlow (Windows, with the voice pack, off unless you turn it on): while it's on, the microphone stays on whenever NetherFlow is open, even minimized. Everything it hears, other people's voices included, is turned into words on your computer only to check for "Hey NetherFlow", and anything else is dropped at once. Nothing is recorded, kept or sent anywhere. To help the recognizer hear names, NetherFlow gives a recognizer on your device the names in your library, never an online speech service. It does not access your location or contacts, or any other photos or files.
The website
NetherFlow's website (volodya-rua.github.io/NetherFlow) has no cookies, no analytics and no forms. It is hosted by GitHub Pages, which receives visitors' IP addresses (GitHub Privacy Statement). Everything its pages need is served from there, and its home page also asks GitHub for NetherFlow's latest release, to link the right downloads. A shared playlist's page works as described above.
Children
NetherFlow is not directed at children under 13 (or under 16 where local law requires). YouTube and other services used by the app have their own minimum-age rules.
Your rights
Depending on where you live (for example under the GDPR, the CCPA, or India's Digital Personal Data Protection Act), you may have rights to access, correct or delete personal data, and to complain to a data-protection authority. The developer holds no personal data it can link to you: NetherFlow's relay keeps only encrypted playlists it can't read and one install count with nothing linking it to anyone, without logs: one edited together is deleted 12 months after its last change, a short share link's a year after it was last opened. The developer never sells or shares your personal data: there is none to sell, and NetherFlow runs no advertising network and no third-party trackers. So there is nothing we could find for you to access, correct or delete; for data held by the services above, contact them using the links in the table. For any privacy question or request, contact the developer, who is also NetherFlow's grievance officer (see the Terms, "Grievances and complaints" and "Contact"); you will get a reply within the time the law requires.
Changes
If this policy changes, the app will show the updated version and ask you to accept it again. Effective date: 2 November 2026.
Licenses & credits
NetherFlow © 2026 Volodya.rua · free and open-source software under the GNU General Public License version 3, with the additional terms below. It comes with no warranty. You may share and change it under that license; its source code is at github.com/volodya-rua/NetherFlow. A HuCla build (human × Claude): its idea, vision and direction are Volodya.rua's, who tests and publishes it; most of its code is written by Claude, Anthropic's AI.
- Credit: every copy and every changed version keeps the credit "NetherFlow by Volodya.rua", with a link to github.com/volodya-rua/NetherFlow, on its about, credits or licenses screen.
- A name and icon of its own: a changed version uses its own name and icon, and doesn't claim to be NetherFlow or to come from Volodya.rua.
- No endorsement: the name Volodya.rua can't be used to promote a changed version.
- No trademark rights: the license gives none to the name NetherFlow, its logo or the name Volodya.rua.
These are additional terms under section 7 of the license; their full wording is in NOTICE. NetherFlow 1.3.1 and earlier were released under the MIT License, and copies of those keep it.
Open-source software
| Component | Used in | License |
|---|---|---|
| Electron © Electron contributors, GitHub Inc. | Desktop app | MIT · license text |
| Chromium and Node.js (bundled with Electron) | Desktop app | BSD-style and others · full list in LICENSES.chromium.html, shipped inside the desktop app |
FFmpeg © the FFmpeg developers (bundled with Electron, as its own library, ffmpeg.dll; on Linux libffmpeg.so) | Desktop app (playing audio and video) | GNU LGPL 2.1 or later · license text · source (the version Electron's Chromium uses) |
| Capacitor © Drifty Co. (Ionic) | Android app | MIT · license text |
| electron-updater © Loopline Systems, electron-builder contributors, with the libraries it uses (builder-util-runtime, fs-extra, js-yaml, semver, sax, argparse and others) | Desktop app (updates) | MIT; ISC, Blue Oak 1.0.0 and Python-2.0 for some of its libraries · all license texts |
| three.js © three.js authors | Desktop app (Redline's 3D races) | MIT · license text · source |
| Fluent Emoji © Microsoft Corporation (the 3D emoji in the lyric styles and Extreme lyrics) | Desktop and Android app | MIT · license text · source |
| Android Jetpack (AndroidX) © The Android Open Source Project | Android app | Apache 2.0 · license text |
| Apache Cordova (Android framework) © The Apache Software Foundation. This product includes software developed at The Apache Software Foundation (http://www.apache.org/). | Android app | Apache 2.0 · license text |
jsQR 1.4.0 © Cosmo Wolfe and the jsQR contributors (jsqr.js) | Desktop and Android app (Library › Import › Scan a QR code) | Apache 2.0 · license text · source |
| ONNX Runtime Web 1.30.0 © Microsoft Corporation, with the third-party code it includes | Windows app (AI karaoke, built in; the voice pack, downloaded only if you choose) and Android app (AI karaoke, downloaded only if you choose) | MIT · license text · third-party notices · source |
| Spleeter 2-stem model © 2019-present Deezer SA (Deezer Research), as converted to ONNX int8 by Fangjun Kuang for sherpa-onnx | Windows app (AI karaoke, built in) and Android app (AI karaoke, downloaded only if you choose) | MIT · license text · source · conversion |
| Whisper base.en model (English) © 2022 OpenAI, as converted to ONNX by Hugging Face's onnx-community | Windows app (the voice pack, downloaded only if you choose) | MIT · license text (its Hugging Face card: Apache 2.0 · license text) · source · conversion |
Typefaces
Anton (Vernon Adams), Instrument Serif (Instrument) and Martian Mono (Evil Martians), all under the SIL Open Font License 1.1, included with the app (Anton, Instrument Serif, Martian Mono license texts).
The lyric font pairs (Settings › Lyrics font), from Google Fonts, included with the app; each under the SIL Open Font License 1.1 unless marked Apache License 2.0, with its license text: Abril Fatface, Playfair Display, Tilt Neon, Yellowtail (Apache 2.0), Press Start 2P, VT323, Rubik Vinyl, DM Serif Display, Rubik Glitch, Space Mono, Sedgwick Ave Display, Permanent Marker (Apache 2.0), Orbitron, Chakra Petch, Unbounded, Cormorant Garamond, Black Ops One, Special Elite (Apache 2.0), Bagel Fat One, Pacifico, Climate Crisis, Libre Bodoni, Pirata One, IM Fell English, Nabla, Bungee Spice, Shrikhand, Kalnia Glaze, Foldit, Fraunces, Cinzel, Sancreek, Corinthia, Shantell Sans, Anybody, Doto, Sour Gummy, Bangers, Xanh Mono, Tilt Prism, Monoton, Limelight, Poiret One, Nosifer, Kaushan Script.
The lyric faces for other scripts (Arabic, Bengali, Devanagari, Gujarati, Gurmukhi, Kannada, Malayalam, Tamil, Telugu and Urdu), from Google Fonts, included with the app; each under the SIL Open Font License 1.1, with its license text: Akaya Kanadaka, Akaya Telivigala, Akshar, Alkatra, Amiri, Anek Bangla, Anek Devanagari, Anek Gujarati, Anek Gurmukhi, Anek Kannada, Anek Malayalam, Anek Tamil, Anek Telugu, Aref Ruqaa, Arima, Baloo 2, Baloo Bhai 2, Baloo Bhaijaan 2, Baloo Chettan 2, Baloo Da 2, Baloo Paaji 2, Baloo Tamma 2, Baloo Tammudu 2, Baloo Thambi 2, Blaka, Chilanka, Coiny, Farsan, Galada, Gayathri, Handjet, Jaini, Kalam, Kavivanar, Kumar One, Lakki Reddy, Lalezar, Langar, Manjari, Marhey, Mina, Modak, Mogra, Noto Kufi Arabic, Noto Nastaliq Urdu, Noto Sans Telugu, Noto Serif Bengali, Noto Serif Gujarati, Noto Serif Gurmukhi, Noto Serif Kannada, Noto Serif Malayalam, Noto Serif Tamil, Noto Serif Telugu, Oi, Rakkas, Rasa, Reem Kufi, Rozha One, Sarpanch, Shrikhand, Tillana, Tiro Bangla, Tiro Devanagari Hindi, Tiro Gurmukhi, Tiro Kannada, Tiro Tamil, Tiro Telugu.
Redline's 3D races
The circuits and what's round them (the ground's cover, forests, buildings, grandstands, barriers, roads) are built from © OpenStreetMap contributors' map data, available under the Open Database License 1.0: so are the files NetherFlow makes from it, race/tracks.json and race/maps/ (tools/race-tracks.js makes them again). The heights are NASA's Shuttle Radar Topography Mission data (SRTM, public domain), through OpenTopoData.
The cars are 3D models by the people named below, under Creative Commons Attribution 4.0, made smaller for NetherFlow (their textures and meshes compressed, the largest simplified, badges, labels and stickers taken off). The cars' makers' names and designs are their trademarks; they don't endorse or sponsor NetherFlow.
- Porsche 911 (930) Turbo 1975 by Lexyc16
- Lamborghini Revuelto by Anatolian Studios
- Hoonicorn - A tribute to Ken Block (Updated) by Chaser-fan
- Lamborghini Temerario by Anatolian Studios
- BMW M4csl by Mpgs Studios
The website
NetherFlow's website also uses Mona Sans (GitHub), under the SIL Open Font License 1.1 (license text), plays three songs by HoliznaCC0, Retro Synths, Saturn and City In The Rearview, which are in the public domain under CC0 1.0 (details), and serves its own copies of three.js (MIT) and Lenis by darkroom.engineering (MIT, its license next to it in the website's vendor/lenis/ folder).
Content and data sources
Song search, artwork and previews: Apple iTunes Search API and YouTube Music. Playback: YouTube (and, behind Extreme lyrics, the song's official music video there), and Audius (artists' own uploads there). Lyrics: LRCLIB, NetEase Cloud Music, Kugou, and YouTube Music (lyrics by LyricFind). Explore's charts, new music, moods and playlists: YouTube Music. Podcasts: Apple's podcast directory and charts, and each show's own feed. Audiobooks: LibriVox's recordings (public domain in the United States), read by its volunteers and kept by the Internet Archive. Headphone correction: AutoEQ © Jaakko Pasanen, its published results under the MIT License, fetched when you choose headphones (not included in the app). Album artwork, songs, videos, podcasts, recordings and lyrics are the property of their respective owners. NetherFlow is not affiliated with any of these services.