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IMPLEMENTATION.md

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Implementation guidelines

How to write your own client.

Requirements

  • You must be able to send messages via a shard's gateway connection.
  • You must be able to intercept voice server & voice state updates from the gateway on your shard connection.

Significant changes v3.7.0 -> v4.0.0

v4.0.0 Migration Guide

All websocket ops are removed as of v4.0.0 and replaced with the following endpoints and json fields:

Older versions

Significant changes v3.6.0 -> v3.7.0

  • Moved HTTP endpoints under the new /v3 path with /version as the only exception.
  • Deprecation of the old HTTP paths.
  • WebSocket handshakes should be done with /v3/websocket. Handshakes on / are now deprecated.
  • Deprecation of all client-to-server messages (play, stop, pause, seek, volume, filters, destroy, voiceUpdate & configureResuming).
  • Addition of REST endpoints intended to replace client requests.
  • Addition of new WebSocket dispatch Ready OP to get sessionId and resume status.
  • Addition of new Session/Player REST API.
  • Addition of /v3/info, replaces /plugins.
  • Deprecation of Track.track in existing endpoints. Use Track.encoded instead.
  • Deprecation of TrackXEvent.track in WebSocket dispatches. Use TrackXEvent.encodedTrack instead.
  • Player now has a state field which contains the same structure as returned by the playerUpdate OP.
v3.7.0 Migration Guide

All websocket ops are deprecated as of v3.7.0 and replaced with the following endpoints and json fields:

Significant changes v3.3 -> v3.4

  • Added filters
  • The error string on the TrackExceptionEvent has been deprecated and replaced by the Exception object following the same structure as the LOAD_FAILED error on /loadtracks.
  • Added the connected boolean to player updates.
  • Added source name to REST api track objects
  • Clients are now requested to make their name known during handshake

Significant changes v2.0 -> v3.0

  • The response of /loadtracks has been completely changed (again since the initial v3.0 pre-release).
  • Lavalink v3.0 now reports its version as a handshake response header. Lavalink-Major-Version has a value of 3 for v3.0 only. It's missing for any older version.

Significant changes v1.3 -> v2.0

With the release of v2.0 many unnecessary ops were removed:

  • connect
  • disconnect
  • validationRes
  • isConnectedRes
  • validationReq
  • isConnectedReq
  • sendWS

With Lavalink 1.x the server had the responsibility of handling Discord VOICE_SERVER_UPDATEs as well as its own internal ratelimiting. This remote handling makes things unnecessarily complicated and adds a lot og points where things could go wrong. One problem we noticed is that since JDA is unaware of ratelimits on the bot's gateway connection, it would keep adding to the ratelimit queue to the gateway. With this update this is now the responsibility of the Lavalink client or the Discord client.

A voice connection is now initiated by forwarding a voiceUpdate (VOICE_SERVER_UPDATE) to the server. When you want to disconnect or move to a different voice channel you must send Discord a new VOICE_STATE_UPDATE. If you want to move your connection to a new Lavalink server you can simply send the VOICE_SERVER_UPDATE to the new node, and the other node will be disconnected by Discord.

Depending on your Discord library, it may be possible to take advantage of the library's OP 4 handling. For instance, the JDA client takes advantage of JDA's websocket write thread to send OP 4s for connects, disconnects and reconnects.

Protocol

Reference

Fields marked with ? are optional and types marked with ? are nullable.

Opening a connection

You can establish a WebSocket connection against the path /v4/websocket.

When opening a websocket connection, you must supply 3 required headers:

Header Name Description
Authorization The password you set in your Lavalink config
User-Id The user id of the bot
Client-Name The name of the client in NAME/VERSION format
Session-Id? * The id of the previous session to resume

*For more information on resuming see Resuming

Example Headers 
Authorization: youshallnotpass
User-Id: 170939974227541168
Client-Name: lavalink-client/2.0.0

Websocket Messages

Websocket messages all follow the following standard format:

Field Type Description
op OP Type The op type
... ... Extra fields depending on the op type
Example Payload 
{
  "op": "...",
  ...
}

OP Types

OP Type Description
ready Dispatched when you successfully connect to the Lavalink node
playerUpdate Dispatched every x seconds with the latest player state
stats Dispatched when the node sends stats once per minute
event Dispatched when player or voice events occur

Ready OP

Dispatched by Lavalink upon successful connection and authorization. Contains fields determining if resuming was successful, as well as the session id.

Field Type Description
resumed bool Whether this session was resumed
sessionId string The Lavalink session id of this connection. Not to be confused with a Discord voice session id
Example Payload 
{
  "op": "ready",
  "resumed": false,
  "sessionId": "..."
}

Player Update OP

Dispatched every x seconds (configurable in application.yml) with the current state of the player.

Field Type Description
guildId string The guild id of the player
state Player State object The player state
Player State
Field Type Description
time int Unix timestamp in milliseconds
position int The position of the track in milliseconds
connected bool Whether Lavalink is connected to the voice gateway
ping int The ping of the node to the Discord voice server in milliseconds (-1 if not connected)
Example Payload 
{
  "op": "playerUpdate",
  "guildId": "...",
  "state": {
    "time": 1500467109,
    "position": 60000,
    "connected": true,
    "ping": 50
  }
}

Stats OP

A collection of stats sent every minute.

Stats Object
Field Type Description
players int The amount of players connected to the node
playingPlayers int The amount of players playing a track
uptime int The uptime of the node in milliseconds
memory Memory object The memory stats of the node
cpu CPU object The cpu stats of the node
frameStats ?Frame Stats object The frame stats of the node. null if the node has no players or when retrieved via /v4/stats
Memory
Field Type Description
free int The amount of free memory in bytes
used int The amount of used memory in bytes
allocated int The amount of allocated memory in bytes
reservable int The amount of reservable memory in bytes
CPU
Field Type Description
cores int The amount of cores the node has
systemLoad float The system load of the node
lavalinkLoad float The load of Lavalink on the node
Frame Stats
Field Type Description
sent int The amount of frames sent to Discord
nulled int The amount of frames that were nulled
deficit int The amount of frames that were deficit
Example Payload 
{
  "op": "stats",
  "players": 1,
  "playingPlayers": 1,
  "uptime": 123456789,
  "memory": {
    "free": 123456789,
    "used": 123456789,
    "allocated": 123456789,
    "reservable": 123456789
  },
  "cpu": {
    "cores": 4,
    "systemLoad": 0.5,
    "lavalinkLoad": 0.5
  },
  "frameStats": {
    "sent": 123456789,
    "nulled": 123456789,
    "deficit": 123456789
  }
}

Event OP

Server dispatched an event. See the Event Types section for more information.

Field Type Description
type EventType The type of event
guildId string The guild id
... ... Extra fields depending on the event
Example Payload 
{
  "op": "event",
  "type": "...",
  "guildId": "...",
  ...
}
Event Types
Event Type Description
TrackStartEvent Dispatched when a track starts playing
TrackEndEvent Dispatched when a track ends
TrackExceptionEvent Dispatched when a track throws an exception
TrackStuckEvent Dispatched when a track gets stuck while playing
WebSocketClosedEvent Dispatched when the websocket connection to Discord voice servers is closed
TrackStartEvent

Dispatched when a track starts playing.

Field Type Description
track Track object The track that started playing
Example Payload 
{
  "op": "event",
  "type": "TrackStartEvent",
  "guildId": "...",
  "track": {
    "encoded": "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
    "info": {
      "identifier": "dQw4w9WgXcQ",
      "isSeekable": true,
      "author": "RickAstleyVEVO",
      "length": 212000,
      "isStream": false,
      "position": 0,
      "title": "Rick Astley - Never Gonna Give You Up",
      "uri": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
      "artworkUrl": "https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg",
      "isrc": null,
      "sourceName": "youtube"
    },
    "pluginInfo": {}
  }
}
TrackEndEvent

Dispatched when a track ends.

Field Type Description
track Track object The track that ended playing
reason TrackEndReason The reason the track ended
Track End Reason
Reason Description May Start Next
finished The track finished playing true
loadFailed The track failed to load true
stopped The track was stopped false
replaced The track was replaced false
cleanup The track was cleaned up false
Example Payload 
{
  "op": "event",
  "type": "TrackEndEvent",
  "guildId": "...",
  "track": {
    "encoded": "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
    "info": {
      "identifier": "dQw4w9WgXcQ",
      "isSeekable": true,
      "author": "RickAstleyVEVO",
      "length": 212000,
      "isStream": false,
      "position": 0,
      "title": "Rick Astley - Never Gonna Give You Up",
      "uri": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
      "artworkUrl": "https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg",
      "isrc": null,
      "sourceName": "youtube"
    },
    "pluginInfo": {}
  },
  "reason": "finished"
}
TrackExceptionEvent

Dispatched when a track throws an exception.

Field Type Description
track Track object The track that threw the exception
exception Exception object The occurred exception
Exception Object
Field Type Description
message ?string The message of the exception
severity Severity The severity of the exception
cause string The cause of the exception
Severity
Severity Description
common The cause is known and expected, indicates that there is nothing wrong with the library itself
suspicious The cause might not be exactly known, but is possibly caused by outside factors. For example when an outside service responds in a format that we do not expect
fault The probable cause is an issue with the library or there is no way to tell what the cause might be. This is the default level and other levels are used in cases where the thrower has more in-depth knowledge about the error
Example Payload 
{
  "op": "event",
  "type": "TrackExceptionEvent",
  "guildId": "...",
  "track": {
    "encoded": "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
    "info": {
      "identifier": "dQw4w9WgXcQ",
      "isSeekable": true,
      "author": "RickAstleyVEVO",
      "length": 212000,
      "isStream": false,
      "position": 0,
      "title": "Rick Astley - Never Gonna Give You Up",
      "uri": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
      "artworkUrl": "https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg",
      "isrc": null,
      "sourceName": "youtube"
    },
    "pluginInfo": {}
  },
  "exception": {
    "message": "...",
    "severity": "common",
    "cause": "..."
  }
}
TrackStuckEvent

Dispatched when a track gets stuck while playing.

Field Type Description
track Track object The track that got stuck
thresholdMs int The threshold in milliseconds that was exceeded
Example Payload 
{
  "op": "event",
  "type": "TrackStuckEvent",
  "guildId": "...",
  "track": {
    "encoded": "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
    "info": {
      "identifier": "dQw4w9WgXcQ",
      "isSeekable": true,
      "author": "RickAstleyVEVO",
      "length": 212000,
      "isStream": false,
      "position": 0,
      "title": "Rick Astley - Never Gonna Give You Up",
      "uri": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
      "artworkUrl": "https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg",
      "isrc": null,
      "sourceName": "youtube"
    },
    "pluginInfo": {}
  },
  "thresholdMs": 123456789
}
WebSocketClosedEvent

Dispatched when an audio WebSocket (to Discord) is closed. This can happen for various reasons (normal and abnormal), e.g. when using an expired voice server update. 4xxx codes are usually bad. See the Discord Docs.

Field Type Description
code int The Discord close event code
reason string The close reason
byRemote bool Whether the connection was closed by Discord
Example Payload 
{
  "op": "event",
  "type": "WebSocketClosedEvent",
  "guildId": "...",
  "code": 4006,
  "reason": "Your session is no longer valid.",
  "byRemote": true
}

REST API

Lavalink exposes a REST API to allow for easy control of the players. Most routes require the Authorization header with the configured password.

Authorization: youshallnotpass

Routes are prefixed with /v3 as of v3.7.0 and /v4 as of v4.0.0. Routes without an API prefix were removed in v4 (except /version).

Error Responses

When Lavalink encounters an error, it will respond with a JSON object containing more information about the error. Include the trace=true query param to also receive the full stack trace.

Field Type Description
timestamp int The timestamp of the error in milliseconds since the Unix epoch
status int The HTTP status code
error string The HTTP status code message
trace? string The stack trace of the error when trace=true as query param has been sent
message string The error message
path string The request path
Example Payload 
{
  "timestamp": 1667857581613,
  "status": 404,
  "error": "Not Found",
  "trace": "...",
  "message": "Session not found",
  "path": "/v4/sessions/xtaug914v9k5032f/players/817327181659111454"
}

Get Players

Returns a list of players in this specific session.

GET /v4/sessions/{sessionId}/players
Player
Field Type Description
guildId string The guild id of the player
track ?Track object The currently playing track
volume int The volume of the player, range 0-1000, in percentage
paused bool Whether the player is paused
state Player State object The state of the player
voice Voice State object The voice state of the player
filters Filters object The filters used by the player
Track
Field Type Description
encoded string The base64 encoded track data
info Track Info object Info about the track
pluginInfo object Addition track info provided by plugins
Track Info
Field Type Description
identifier string The track identifier
isSeekable bool Whether the track is seekable
author string The track author
length int The track length in milliseconds
isStream bool Whether the track is a stream
position int The track position in milliseconds
title string The track title
uri ?string The track uri
artworkUrl ?string The track artwork url
isrc ?string The track ISRC
sourceName string The track source name
Voice State
Field Type Description
token string The Discord voice token to authenticate with
endpoint string The Discord voice endpoint to connect to
sessionId string The Discord voice session id to authenticate with

token, endpoint, and sessionId are the 3 required values for connecting to one of Discord's voice servers. sessionId is provided by the Voice State Update event sent by Discord, whereas the endpoint and token are provided with the Voice Server Update. Please refer to https://discord.com/developers/docs/topics/gateway-events#voice

Example Payload 
[
  {
    "guildId": "...",
    "track": {
      "encoded": "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
      "info": {
        "identifier": "dQw4w9WgXcQ",
        "isSeekable": true,
        "author": "RickAstleyVEVO",
        "length": 212000,
        "isStream": false,
        "position": 60000,
        "title": "Rick Astley - Never Gonna Give You Up",
        "uri": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
        "artworkUrl": "https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg",
        "isrc": null,
        "sourceName": "youtube"
      },
      "pluginInfo": {}
    },
    "volume": 100,
    "paused": false,
    "state": {
      "time": 1500467109,
      "position": 60000,
      "connected": true,
      "ping": 50
    },
    "voice": {
      "token": "...",
      "endpoint": "...",
      "sessionId": "..."
    },
    "filters": { ... }
  },
  ...
]

Get Player

Returns the player for this guild in this session.

GET /v4/sessions/{sessionId}/players/{guildId}

Response:

Player object

Example Payload 
{
  "guildId": "...",
  "track": {
    "encoded": "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
    "info": {
      "identifier": "dQw4w9WgXcQ",
      "isSeekable": true,
      "author": "RickAstleyVEVO",
      "length": 212000,
      "isStream": false,
      "position": 60000,
      "title": "Rick Astley - Never Gonna Give You Up",
      "uri": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
      "artworkUrl": "https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg",
      "isrc": null,
      "sourceName": "youtube"
    }
  },
  "volume": 100,
  "paused": false,
  "state": {
    "time": 1500467109,
    "position": 60000,
    "connected": true,
    "ping": 50
  },
  "voice": {
    "token": "...",
    "endpoint": "...",
    "sessionId": "..."
  },
  "filters": { ... }
}

Update Player

Updates or creates the player for this guild if it doesn't already exist.

PATCH /v4/sessions/{sessionId}/players/{guildId}?noReplace=true

Query Params:

Field Type Description
noReplace? bool Whether to replace the current track with the new track. Defaults to false

Request:

Field Type Description
encodedTrack? * ?string The base64 encoded track to play. null stops the current track
identifier? * string The identifier of the track to play
position? int The track position in milliseconds
endTime? ?int The track end time in milliseconds (must be > 0). null resets this if it was set previously
volume? int The player volume, in percentage, from 0 to 1000
paused? bool Whether the player is paused
filters? Filters object The new filters to apply. This will override all previously applied filters
voice? Voice State object Information required for connecting to Discord

Note

  • * encodedTrack and identifier are mutually exclusive.
  • sessionId in the path should be the value from the ready op.

When identifier is used, Lavalink will try to resolve the identifier as a single track. An HTTP 400 error is returned when resolving a playlist, search result, or no tracks.

Example Payload 
{
  "encodedTrack": "...",
  "identifier": "...",
  "startTime": 0,
  "endTime": 0,
  "volume": 100,
  "position": 32400,
  "paused": false,
  "filters": { ... },
  "voice": {
    "token": "...",
    "endpoint": "...",
    "sessionId": "..."
  }
}

Response:

Player object

Example Payload 
{
  "guildId": "...",
  "track": {
    "encoded": "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
    "info": {
      "identifier": "dQw4w9WgXcQ",
      "isSeekable": true,
      "author": "RickAstleyVEVO",
      "length": 212000,
      "isStream": false,
      "position": 60000,
      "title": "Rick Astley - Never Gonna Give You Up",
      "uri": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
      "artworkUrl": "https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg",
      "isrc": null,
      "sourceName": "youtube"
    }
  },
  "volume": 100,
  "paused": false,
  "state": {
    "time": 1500467109,
    "position": 60000,
    "connected": true,
    "ping": 50         
  },
  "voice": {
    "token": "...",
    "endpoint": "...",
    "sessionId": "..."
  },
  "filters": { ... }
}

Filters

Filters are used in above requests and look like this

Field Type Description
volume? float Adjusts the player volume from 0.0 to 5.0, where 1.0 is 100%. Values >1.0 may cause clipping
equalizer? array of Equalizer objects Adjusts 15 different bands
karaoke? Karaoke object Eliminates part of a band, usually targeting vocals
timescale? Timescale object Changes the speed, pitch, and rate
tremolo? Tremolo object Creates a shuddering effect, where the volume quickly oscillates
vibrato? Vibrato object Creates a shuddering effect, where the pitch quickly oscillates
rotation? Rotation object Rotates the audio around the stereo channels/user headphones (aka Audio Panning)
distortion? Distortion object Distorts the audio
channelMix? Channel Mix object Mixes both channels (left and right)
lowPass? Low Pass object Filters higher frequencies
pluginFilters? map of Plugin Filter objects Filter plugin configurations
Equalizer

There are 15 bands (0-14) that can be changed. "gain" is the multiplier for the given band. The default value is 0. Valid values range from -0.25 to 1.0, where -0.25 means the given band is completely muted, and 0.25 means it is doubled. Modifying the gain could also change the volume of the output.

Band Frequencies
Band Frequency
0 25 Hz
1 40 Hz
2 63 Hz
3 100 Hz
4 160 Hz
5 250 Hz
6 400 Hz
7 630 Hz
8 1000 Hz
9 1600 Hz
10 2500 Hz
11 4000 Hz
12 6300 Hz
13 10000 Hz
14 16000 Hz
Field Type Description
band int The band (0 to 14)
gain float The gain (-0.25 to 1.0)
Karaoke

Uses equalization to eliminate part of a band, usually targeting vocals.

Field Type Description
level? float The level (0 to 1.0 where 0.0 is no effect and 1.0 is full effect)
monoLevel? float The mono level (0 to 1.0 where 0.0 is no effect and 1.0 is full effect)
filterBand? float The filter band (in Hz)
filterWidth? float The filter width
Timescale

Changes the speed, pitch, and rate. All default to 1.0.

Field Type Description
speed? float The playback speed 0.0 ≤ x
pitch? float The pitch 0.0 ≤ x
rate? float The rate 0.0 ≤ x
Tremolo

Uses amplification to create a shuddering effect, where the volume quickly oscillates. Demo: https://en.wikipedia.org/wiki/File:Fuse_Electronics_Tremolo_MK-III_Quick_Demo.ogv

Field Type Description
frequency? float The frequency 0.0 < x
depth? float The tremolo depth 0.0 < x ≤ 1.0
Vibrato

Similar to tremolo. While tremolo oscillates the volume, vibrato oscillates the pitch.

Field Type Description
frequency? float The frequency 0.0 < x ≤ 14.0
depth? float The vibrato depth 0.0 < x ≤ 1.0
Rotation

Rotates the sound around the stereo channels/user headphones (aka Audio Panning). It can produce an effect similar to https://youtu.be/QB9EB8mTKcc (without the reverb).

Field Type Description
rotationHz? float The frequency of the audio rotating around the listener in Hz. 0.2 is similar to the example video above
Distortion

Distortion effect. It can generate some pretty unique audio effects.

Field Type Description
sinOffset? float The sin offset
sinScale? float The sin scale
cosOffset? float The cos offset
cosScale? float The cos scale
tanOffset? float The tan offset
tanScale? float The tan scale
offset? float The offset
scale? float The scale
Channel Mix

Mixes both channels (left and right), with a configurable factor on how much each channel affects the other. With the defaults, both channels are kept independent of each other. Setting all factors to 0.5 means both channels get the same audio.

Field Type Description
leftToLeft? float The left to left channel mix factor (0.0 ≤ x ≤ 1.0)
leftToRight? float The left to right channel mix factor (0.0 ≤ x ≤ 1.0)
rightToLeft? float The right to left channel mix factor (0.0 ≤ x ≤ 1.0)
rightToRight? float The right to right channel mix factor (0.0 ≤ x ≤ 1.0)
Low Pass

Higher frequencies get suppressed, while lower frequencies pass through this filter, thus the name low pass. Any smoothing values equal to or less than 1.0 will disable the filter.

Field Type Description
smoothing? float The smoothing factor (1.0 < x)
Plugin Filter

Plugins can add their own filters. The key is the name of the plugin, and the value is the configuration for that plugin. The configuration is plugin specific. See Plugins for more plugin information.

Example Payload 
{
  "volume": 1.0,
  "equalizer": [
    {
      "band": 0,
      "gain": 0.2
    }
  ],
  "karaoke": {
    "level": 1.0,
    "monoLevel": 1.0,
    "filterBand": 220.0,
    "filterWidth": 100.0
  },
  "timescale": {
    "speed": 1.0,
    "pitch": 1.0,
    "rate": 1.0
  },
  "tremolo": {
    "frequency": 2.0,
    "depth": 0.5
  },
  "vibrato": {
    "frequency": 2.0,
    "depth": 0.5
  },
  "rotation": {
    "rotationHz": 0
  },
  "distortion": {
    "sinOffset": 0.0,
    "sinScale": 1.0,
    "cosOffset": 0.0,
    "cosScale": 1.0,
    "tanOffset": 0.0,
    "tanScale": 1.0,
    "offset": 0.0,
    "scale": 1.0
  },
  "channelMix": {
    "leftToLeft": 1.0,
    "leftToRight": 0.0,
    "rightToLeft": 0.0,
    "rightToRight": 1.0
  },
  "lowPass": {
    "smoothing": 20.0
  },
  "pluginFilters": {
    "myPlugin": {
      "myPluginKey": "myPluginValue"
    }
  }
}

Destroy Player

Destroys the player for this guild in this session.

DELETE /v4/sessions/{sessionId}/players/{guildId}

Response:

204 - No Content

Update Session

Updates the session with the resuming state and timeout.

PATCH /v4/sessions/{sessionId}

Request:

Field Type Description
resuming? bool Whether resuming is enabled for this session or not
timeout? int The timeout in seconds (default is 60s)
Example Payload 
{
  "resuming": false,
  "timeout": 0
}

Response:

Field Type Description
resuming bool Whether resuming is enabled for this session or not
timeout int The timeout in seconds (default is 60s)
Example Payload 
{
  "resuming": true,
  "timeout": 60
}

Track Loading

This endpoint is used to resolve audio tracks for use with the Update Player endpoint.

GET /v4/loadtracks?identifier=dQw4w9WgXcQ

Response:

Track Loading Result
Field Type Description
loadType LoadResultType The type of the result
data LoadResultData The data of the result
Load Result Type
Load Result Type Description
track A track has been loaded
playlist A playlist has been loaded
search A search result has been loaded
empty There has been no matches for your identifier
error Loading has failed with an error
Load Result Data
Load Result Data - Track

Track object with the loaded track.

Example Payload 
{
  "loadType": "track",
  "data": {
    "encoded": "...",
    "info": { ... },
    "pluginInfo": { ... }
  }
}
Load Result Data - Playlist
Field Type Description
info PlaylistInfo object The info of the playlist
pluginInfo Object Addition playlist info provided by plugins
tracks array of Track objects The tracks of the playlist
Playlist Info
Field Type Description
name string The name of the playlist
selectedTrack int The selected track of the playlist (-1 if no track is selected)
Example Payload 
{
  "loadType": "playlist",
  "data": {
    "info": { ... },
    "pluginInfo": { ... },
    "tracks": [ ... ]
  }
}
Load Result Data - Search

Array of Track objects from the search result.

Example Payload 
{
  "loadType": "search",
  "data": [
    {
      "encoded": "...",
      "info": { ... },
      "pluginInfo": { ... }
    },
    ...
  ]
}
Load Result Data - Empty

Empty object.

Example Payload 
{
  "loadType": "empty",
  "data": {}
}
Load Result Data - Error

Exception object with the error.

Example Payload 
{
  "loadType": "error",
  "data": { 
    "message": "Something went wrong",
    "severity": "fault",
    "cause": "..."
  }
}

Track Searching

Lavalink supports searching via YouTube, YouTube Music, and Soundcloud. To search, you must prefix your identifier with ytsearch:, ytmsearch: or scsearch: respectively.

When a search prefix is used, the returned loadType will be search. Note that disabling the respective source managers renders these search prefixes useless. Plugins may also implement prefixes to allow for more search engines to be utilised.

Track Decoding

Decode a single track into its info, where BASE64 is the encoded base64 data.

GET /v4/decodetrack?encodedTrack=BASE64

Response:

Track object

Example Payload 
{
  "encoded": "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
  "info": {
    "identifier": "dQw4w9WgXcQ",
    "isSeekable": true,
    "author": "RickAstleyVEVO",
    "length": 212000,
    "isStream": false,
    "position": 0,
    "title": "Rick Astley - Never Gonna Give You Up",
    "uri": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
    "artworkUrl": "https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg",
    "isrc": null,
    "sourceName": "youtube"
  },
  "pluginInfo": {}
}

Decodes multiple tracks into their info

POST /v4/decodetracks

Request:

Array of track data strings

Example Payload 
[
  "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
  ...
]

Response:

Array of Track objects

Example Payload 
[
  {
    "encoded": "QAAAjQIAJVJpY2sgQXN0bGV5IC0gTmV2ZXIgR29ubmEgR2l2ZSBZb3UgVXAADlJpY2tBc3RsZXlWRVZPAAAAAAADPCAAC2RRdzR3OVdnWGNRAAEAK2h0dHBzOi8vd3d3LnlvdXR1YmUuY29tL3dhdGNoP3Y9ZFF3NHc5V2dYY1EAB3lvdXR1YmUAAAAAAAAAAA==",
    "info": {
      "identifier": "dQw4w9WgXcQ",
      "isSeekable": true,
      "author": "RickAstleyVEVO",
      "length": 212000,
      "isStream": false,
      "position": 0,
      "title": "Rick Astley - Never Gonna Give You Up",
      "uri": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
      "artworkUrl": "https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg",
      "isrc": null,
      "sourceName": "youtube"
    },
    "pluginInfo": {}
  },
  ...
]

Get Lavalink info

Request Lavalink information.

GET /v4/info

Response:

Info Response
Field Type Description
version Version object The version of this Lavalink server
buildTime int The millisecond unix timestamp when this Lavalink jar was built
git Git object The git information of this Lavalink server
jvm string The JVM version this Lavalink server runs on
lavaplayer string The Lavaplayer version being used by this server
sourceManagers array of strings The enabled source managers for this server
filters array of strings The enabled filters for this server
plugins array of Plugin objects The enabled plugins for this server
Version Object

Parsed Semantic Versioning 2.0.0. See https://semver.org/ for more info

Field Type Description
semver string The full version string of this Lavalink server
major int The major version of this Lavalink server
minor int The minor version of this Lavalink server
patch int The patch version of this Lavalink server
preRelease ?string The pre-release version according to semver as a . separated list of identifiers
build ?string The build metadata according to semver as a . separated list of identifiers
Git Object
Field Type Description
branch string The branch this Lavalink server was built on
commit string The commit this Lavalink server was built on
commitTime int The millisecond unix timestamp for when the commit was created
Plugin Object
Field Type Description
name string The name of the plugin
version string The version of the plugin
Example Payload 
{
  "version": {
    "string": "3.7.0-rc.1+test",
    "major": 3,
    "minor": 7,
    "patch": 0,
    "preRelease": "rc.1",
    "build": "test"
  },
  "buildTime": 1664223916812,
  "git": {
    "branch": "master",
    "commit": "85c5ab5",
    "commitTime": 1664223916812
  },
  "jvm": "18.0.2.1",
  "lavaplayer": "1.3.98.4-original",
  "sourceManagers": [
    "youtube",
    "soundcloud"
  ],
  "filters": [
    "equalizer",
    "karaoke",
    "timescale",
    "channelMix"
  ],
  "plugins": [
    {
      "name": "some-plugin",
      "version": "1.0.0"
    },
    {
      "name": "foo-plugin",
      "version": "1.2.3"
    }
  ]
}

Get Lavalink stats

Request Lavalink statistics.

GET /v4/stats

Response:

frameStats is always missing for this endpoint. Stats object

Example Payload 
{
  "players": 1,
  "playingPlayers": 1,
  "uptime": 123456789,
  "memory": {
    "free": 123456789,
    "used": 123456789,
    "allocated": 123456789,
    "reservable": 123456789
  },
  "cpu": {
    "cores": 4,
    "systemLoad": 0.5,
    "lavalinkLoad": 0.5
  }
}

Get Lavalink version

Request Lavalink version.

GET /version

Response:

4.0.0

RoutePlanner API

Additionally, there are a few REST endpoints for the ip rotation extension.

Get RoutePlanner status

GET /v4/routeplanner/status

Response:

Field Type Description
class ?Route Planner Type The name of the RoutePlanner implementation being used by this server
details ?Details object The status details of the RoutePlanner
Route Planner Types
Route Planner Type Description
RotatingIpRoutePlanner IP address used is switched on ban. Recommended for IPv4 blocks or IPv6 blocks smaller than a /64.
NanoIpRoutePlanner IP address used is switched on clock update. Use with at least 1 /64 IPv6 block.
RotatingNanoIpRoutePlanner IP address used is switched on clock update, rotates to a different /64 block on ban. Use with at least 2x /64 IPv6 blocks.
BalancingIpRoutePlanner IP address used is selected at random per request. Recommended for larger IP blocks.
Details Object
Field Type Description Valid Types
ipBlock IP Block object The ip block being used all
failingAddresses array of Failing Addresses The failing addresses all
rotateIndex string The number of rotations RotatingIpRoutePlanner
ipIndex string The current offset in the block RotatingIpRoutePlanner
currentAddress string The current address being used RotatingIpRoutePlanner
currentAddressIndex string The current offset in the ip block NanoIpRoutePlanner, RotatingNanoIpRoutePlanner
blockIndex string The information in which /64 block ips are chosen. This number increases on each ban. RotatingNanoIpRoutePlanner
IP Block Object
Field Type Description
type IP Block Type The type of the ip block
size string The size of the ip block
IP Block Type
IP Block Type Description
Inet4Address The ipv4 block type
Inet6Address The ipv6 block type
Failing Address Object
Field Type Description
failingAddress string The failing address
failingTimestamp int The timestamp when the address failed
failingTime string The timestamp when the address failed as a pretty string
Example Payload 
{
  "class": "RotatingNanoIpRoutePlanner",
  "details": {
    "ipBlock": {
      "type": "Inet6Address",
      "size": "1208925819614629174706176"
    },
    "failingAddresses": [
      {
        "failingAddress": "/1.0.0.0",
        "failingTimestamp": 1573520707545,
        "failingTime": "Mon Nov 11 20:05:07 EST 2019"
      }
    ],
    "blockIndex": "0",
    "currentAddressIndex": "36792023813"
  }
}

Unmark a failed address

POST /v4/routeplanner/free/address

Request:

Field Type Description
address string The address to unmark as failed. This address must be in the same ip block.
Example Payload 
{
  "address": "1.0.0.1"
}

Response:

204 - No Content

Unmark all failed address

POST /v4/routeplanner/free/all

Response:

204 - No Content

Resuming Lavalink Sessions

What happens after your client disconnects is dependent on whether the session has been configured for resuming.

  • If resuming is disabled all voice connections are closed immediately.
  • If resuming is enabled all music will continue playing. You will then be able to resume your session, allowing you to control the players again.

To enable resuming, you must call the Update Session endpoint with the resuming and timeout.

To resume a session, specify the session id in your WebSocket handshake request headers:

Session-Id: The id of the session you want to resume.

You can tell if your session was resumed by looking at the handshake response header Session-Resumed which is either true or false.

Session-Resumed: true

In case your websocket library doesn't support reading headers you can listen for the ready op and check the resumed field.

When a session is paused, any events that would normally have been sent are queued up. When the session is resumed, this queue is then emptied and the events are replayed.

Special notes

  • When your shard's main WS connection dies, so does all your Lavalink audio connections

    • This also includes resumes

  • If Lavalink-Server suddenly dies (think SIGKILL) the client will have to terminate any audio connections by sending this event to Discord:

{
  "op": 4,
  "d": {
    "self_deaf": false,
    "guild_id": "GUILD_ID_HERE",
    "channel_id": null,
    "self_mute": false
  }
}

Common pitfalls

Admittedly Lavalink isn't inherently the most intuitive thing ever, and people tend to run into the same mistakes over again. Please double-check the following if you run into problems developing your client, and you can't connect to a voice channel or play audio:

  1. Check that you are intercepting VOICE_SERVER_UPDATEs and VOICE_STATE_UPDATEs to Lavalink. You only need the endpoint, token, and session_id.
  2. Check that you aren't expecting to hear audio when you have forgotten to queue something up OR forgotten to join a voice channel.
  3. Check that you are not trying to create a voice connection with your Discord library.
  4. When in doubt, check the debug logfile at /logs/debug.log.