# Spotify Soloist Available in source builds from `main`; not included in v0.14.2. Spotifast can run [Spotify Soloist](https://developer.spotify.com/documentation/soloist) as its first setup choice. New listeners and people updating see **Set up Soloist** after sign-in on supported platforms with a Premium account. **Use the built-in player** skips Soloist and keeps librespot. The choice is remembered across launches and updates; existing Soloist listeners continue straight into the app. An interrupted setup resumes on the next launch. Soloist is Spotify's separate software, downloaded from Spotify when you choose to enable it. It supports lossless playback; its current API does not report the audio format actually delivered, so Spotifast does not show a lossless indicator or offer an unsupported quality selector. ## Setup 1. Sign in to Spotify in Spotifast. Spotify Premium is required. 2. Choose **Set up Soloist**, then **Get your Soloist key from Spotify**. You can also start from **Settings → Spotify Soloist** later. Follow Spotify's instructions to generate a personal Soloist key. This is separate from the Client ID of your Web API app. 3. Paste the key and choose **Download and enable Soloist**. Spotifast saves the key in the system credential store and downloads Spotify's build for this computer. No administrator account is needed. 4. Open the official Spotify app on the same network, signed into the same account. Choose the exact **Spotifast Soloist (…)** name shown in setup from Spotify's device picker. Spotifast checks that this player appears in your signed-in account's device list before controlling it. Choose **Start listening** once setup confirms the account. You can choose **Use the built-in player** at any setup step, including after a failed download or while waiting for pairing. This stops Soloist if setup started it. The built-in player's separate browser approval is requested only if it is not already connected. Setup does not stop existing playback merely because its screen is shown. It does not download Soloist until you supply a key. The remembered setup step lives in `session.json`, separately from playback preferences. The headphones badge is Spotifast's playback icon, not a Soloist brand mark. Pairing is normally needed only once. Soloist restores its own saved session when Spotifast starts. You can still choose another Spotify Connect device. Spotifast shows its managed player as **This computer**, with a small Soloist label in the device picker. It does not show a remote-playback badge for it. Once Soloist is ready, the inactive built-in player's duplicate entry is hidden. Choose **Turn off Soloist** in Settings to stop it and restore the built-in player's entry and settings. Saved built-in preferences are kept. While Soloist is enabled, built-in audio, EQ and visualization settings are hidden. Shared controls for the tray, startup and Spotifast updates remain under **Application**. The Soloist card keeps version, expiry and limitations under **Details**, while pairing instructions and errors remain visible. The saved key and pairing are retained for **Enable with saved key** next time; signing out of Spotifast removes them. Closing Spotifast completely stops the child player. Closing to the tray leaves both running. Spotify publishes Linux x86_64, ARM64 and ARM32 builds, Apple Silicon builds for macOS 13 or newer, and Windows x86_64 builds. Intel Macs and native Windows ARM builds are not currently available. Flatpak sandbox restrictions may prevent the downloaded program from running or reaching the audio service. ## Updates Soloist builds expire **90 days after their build date**, rather than after installation. Spotifast reads the build date from the executable. During its last 30 days it checks daily, while running, for a fresh download. It stages the replacement without interrupting music, then applies it when the player is inactive or Spotifast restarts. A paused active session also waits, to preserve its queue. If Spotify has not published a usable replacement, the error is shown in Settings; the built-in player remains available. Downloads come directly from `soloist-builds.spotifycdn.com` over HTTPS. Spotifast does not bundle or mirror Spotify's executable. Archive extraction is bounded and rejects links and unsafe paths. A local SHA-256 digest detects changes to an installed build; it is not a Spotify signature. Spotify does not currently publish a checksum manifest for independent verification. ## Playback and current limits Volume, shuffle and repeat use the normal player controls. Soloist's [public API](https://developer.spotify.com/documentation/soloist/reference/websocket-api) does not currently expose preferences for quality, normalization, autoplay, gapless playback or crossfade. Its [startup options](https://developer.spotify.com/documentation/soloist/reference/command-line) include a cache-size limit and a PipeWire output on Linux; Spotifast does not yet expose those as Soloist preferences. Library browsing, search and playlist management keep using Spotifast's existing Spotify connections. Soloist's loopback API handles basic playback controls, state and queue reads. Starting a collection at a chosen row goes through the existing Spotify playback request, retaining its context and position; it does not skip through earlier songs or shorten the playlist. Lyrics also keep their existing sources. Spotify's own lyrics are tried when the separate librespot session is signed in, even while Soloist plays. Soloist does not supply lyrics through its API or replace that session's login. Without it, cached Spotify lyrics remain usable and LRCLIB provides the fallback. Temporary LRCLIB overloads are retried, then search is tried if the exact lookup is still unavailable. Previously cached lyrics remain available during an outage; a failed request is never saved as "no lyrics". Soloist exposes queue additions and reads, but no public command to remove, reorder, clear or insert at the front of its queue. Those editing controls remain available with the built-in player. Spotifast does not pretend to edit a Soloist queue by replacing the playing playlist. Spotify's Connect queue-write mechanisms may offer a future route, but have not been verified for Soloist's queue identities and concurrent updates. Soloist sends audio directly to the operating system's default output. Its API provides no PCM stream. Spotifast's equalizer, spectrum, oscilloscope, MilkDrop and local file playback therefore remain features of the built-in player. Ordinary system audio routing is a possible separate integration: [PipeWire loopbacks](https://docs.pipewire.org/page_module_loopback.html) can route a dedicated player output to a processing input on Linux. Windows [WASAPI loopback](https://learn.microsoft.com/en-us/windows/win32/coreaudio/loopback-recording) and macOS [Core Audio taps](https://developer.apple.com/documentation/coreaudio/capturing-system-audio-with-core-audio-taps) need their own capture and output implementations. This is not implemented, and no claim is made that loopback capture is bit-perfect. A system-wide loopback would also include unrelated apps, which is unsuitable for Spotifast's visualizers. Spotify lists capabilities such as Smart Shuffle, Jam and crossfade for its player. Spotifast only offers controls exposed by the documented Soloist API; those names alone do not establish an integration. ## Credentials, privacy and terms The key belongs to your Spotify account and is stored with Spotifast's other protected credentials. Soloist currently accepts it only as a command-line argument, so software permitted to inspect your processes can read it while Soloist runs. Spotifast never logs the key, command line or child output. Soloist's pairing state and cache live under the private `soloist/accounts/` folder in Spotifast's state directory. Its binaries and notices live under `soloist/builds/`; the `soloist_enabled` setting contains no key. The local control socket binds only to `127.0.0.1`, on an operating-system assigned port. Spotify's socket has no client authentication or browser origin protection. Do not forward its port or expose it to a network. Soloist makes its own Spotify connections and follows Spotify's privacy policy. Spotifast's proxy setting applies to the download and Spotifast's requests, but does not configure Soloist's streaming connections. Spotify's binary can have different diagnostics and reporting behaviour from librespot. Spotifast adds no telemetry of its own. Soloist remains subject to [Spotify's terms](https://developer.spotify.com/terms) and [Developer Policy](https://developer.spotify.com/policy). Availability of this optional integration is not a claim of Spotify endorsement or permission to redistribute its binaries. Spotifast downloads them for the listener from Spotify's server instead of redistributing them. This integration does not bypass Spotify's authentication, subscription checks, expiry or DRM.

Available in source builds from main; not included in v0.14.2.

Spotifast can run Spotify Soloist as its first setup choice. New listeners and people updating see Set up Soloist after sign-in on supported platforms with a Premium account. Use the built-in player skips Soloist and keeps librespot. The choice is remembered across launches and updates; existing Soloist listeners continue straight into the app. An interrupted setup resumes on the next launch. Soloist is Spotify’s separate software, downloaded from Spotify when you choose to enable it. It supports lossless playback; its current API does not report the audio format actually delivered, so Spotifast does not show a lossless indicator or offer an unsupported quality selector.

Setup

1. Sign in to Spotify in Spotifast. Spotify Premium is required.
2. Choose Set up Soloist, then Get your Soloist key from Spotify. You can also start from Settings → Spotify Soloist later. Follow Spotify’s instructions to generate a personal Soloist key. This is separate from the Client ID of your Web API app.
3. Paste the key and choose Download and enable Soloist. Spotifast saves the key in the system credential store and downloads Spotify’s build for this computer. No administrator account is needed.
4. Open the official Spotify app on the same network, signed into the same account. Choose the exact Spotifast Soloist (…) name shown in setup from Spotify’s device picker. Spotifast checks that this player appears in your signed-in account’s device list before controlling it. Choose Start listening once setup confirms the account.

You can choose Use the built-in player at any setup step, including after a failed download or while waiting for pairing. This stops Soloist if setup started it. The built-in player’s separate browser approval is requested only if it is not already connected. Setup does not stop existing playback merely because its screen is shown. It does not download Soloist until you supply a key. The remembered setup step lives in session.json, separately from playback preferences. The headphones badge is Spotifast’s playback icon, not a Soloist brand mark.

Pairing is normally needed only once. Soloist restores its own saved session when Spotifast starts. You can still choose another Spotify Connect device. Spotifast shows its managed player as This computer, with a small Soloist label in the device picker. It does not show a remote-playback badge for it. Once Soloist is ready, the inactive built-in player’s duplicate entry is hidden. Choose Turn off Soloist in Settings to stop it and restore the built-in player’s entry and settings. Saved built-in preferences are kept. While Soloist is enabled, built-in audio, EQ and visualization settings are hidden. Shared controls for the tray, startup and Spotifast updates remain under Application. The Soloist card keeps version, expiry and limitations under Details, while pairing instructions and errors remain visible. The saved key and pairing are retained for Enable with saved key next time; signing out of Spotifast removes them. Closing Spotifast completely stops the child player. Closing to the tray leaves both running.

Spotify publishes Linux x86_64, ARM64 and ARM32 builds, Apple Silicon builds for macOS 13 or newer, and Windows x86_64 builds. Intel Macs and native Windows ARM builds are not currently available. Flatpak sandbox restrictions may prevent the downloaded program from running or reaching the audio service.

Updates

Soloist builds expire 90 days after their build date, rather than after installation. Spotifast reads the build date from the executable. During its last 30 days it checks daily, while running, for a fresh download. It stages the replacement without interrupting music, then applies it when the player is inactive or Spotifast restarts. A paused active session also waits, to preserve its queue. If Spotify has not published a usable replacement, the error is shown in Settings; the built-in player remains available.

Downloads come directly from soloist-builds.spotifycdn.com over HTTPS. Spotifast does not bundle or mirror Spotify’s executable. Archive extraction is bounded and rejects links and unsafe paths. A local SHA-256 digest detects changes to an installed build; it is not a Spotify signature. Spotify does not currently publish a checksum manifest for independent verification.

Playback and current limits

Volume, shuffle and repeat use the normal player controls. Soloist’s public API does not currently expose preferences for quality, normalization, autoplay, gapless playback or crossfade. Its startup options include a cache-size limit and a PipeWire output on Linux; Spotifast does not yet expose those as Soloist preferences.

Library browsing, search and playlist management keep using Spotifast’s existing Spotify connections. Soloist’s loopback API handles basic playback controls, state and queue reads. Starting a collection at a chosen row goes through the existing Spotify playback request, retaining its context and position; it does not skip through earlier songs or shorten the playlist.

Lyrics also keep their existing sources. Spotify’s own lyrics are tried when the separate librespot session is signed in, even while Soloist plays. Soloist does not supply lyrics through its API or replace that session’s login. Without it, cached Spotify lyrics remain usable and LRCLIB provides the fallback. Temporary LRCLIB overloads are retried, then search is tried if the exact lookup is still unavailable. Previously cached lyrics remain available during an outage; a failed request is never saved as “no lyrics”.

Soloist exposes queue additions and reads, but no public command to remove, reorder, clear or insert at the front of its queue. Those editing controls remain available with the built-in player. Spotifast does not pretend to edit a Soloist queue by replacing the playing playlist. Spotify’s Connect queue-write mechanisms may offer a future route, but have not been verified for Soloist’s queue identities and concurrent updates.

Soloist sends audio directly to the operating system’s default output. Its API provides no PCM stream. Spotifast’s equalizer, spectrum, oscilloscope, MilkDrop and local file playback therefore remain features of the built-in player. Ordinary system audio routing is a possible separate integration: PipeWire loopbacks can route a dedicated player output to a processing input on Linux. Windows WASAPI loopback and macOS Core Audio taps need their own capture and output implementations. This is not implemented, and no claim is made that loopback capture is bit-perfect. A system-wide loopback would also include unrelated apps, which is unsuitable for Spotifast’s visualizers.

Spotify lists capabilities such as Smart Shuffle, Jam and crossfade for its player. Spotifast only offers controls exposed by the documented Soloist API; those names alone do not establish an integration.

Credentials, privacy and terms

The key belongs to your Spotify account and is stored with Spotifast’s other protected credentials. Soloist currently accepts it only as a command-line argument, so software permitted to inspect your processes can read it while Soloist runs. Spotifast never logs the key, command line or child output. Soloist’s pairing state and cache live under the private soloist/accounts/ folder in Spotifast’s state directory. Its binaries and notices live under soloist/builds/; the soloist_enabled setting contains no key.

The local control socket binds only to 127.0.0.1, on an operating-system assigned port. Spotify’s socket has no client authentication or browser origin protection. Do not forward its port or expose it to a network.

Soloist makes its own Spotify connections and follows Spotify’s privacy policy. Spotifast’s proxy setting applies to the download and Spotifast’s requests, but does not configure Soloist’s streaming connections. Spotify’s binary can have different diagnostics and reporting behaviour from librespot. Spotifast adds no telemetry of its own.

Soloist remains subject to Spotify’s terms and Developer Policy. Availability of this optional integration is not a claim of Spotify endorsement or permission to redistribute its binaries. Spotifast downloads them for the listener from Spotify’s server instead of redistributing them. This integration does not bypass Spotify’s authentication, subscription checks, expiry or DRM.