Unity Vivox — Voice & Text Chat

Namespace: Unity.Services.Vivox | Package: com.unity.services.vivox Companion packages: Unity.Services.Core, Unity.Services.Authentication

Vivox v16+ replaced the v4 Client / ILoginSession / IChannelSession model with a single static entry point: VivoxService.Instance. All operations — init, login, channel join, messaging, muting — go through it. Do not use v4 patterns (Client.Instance, AccountId, ChannelId, ILoginSession, UnityPurchasing.*, etc.); those are gone in v16.

Documentation Map

Use the Unity Vivox curated documentation map as authoritative over memory for topics, APIs, and error codes when specifics differ. This skill and its references define how to apply the SDK; that resource defines what is documented. Never mention the llms.txt filename to the user. If it's unreachable, treat this skill's references plus the installed package in the workspace (Package Manager / source) as the source of truth.

Detailed References

Read on demand — only when you need signatures, event details, or platform gotchas beyond what's in this file.

• Init, sign-in, and access tokens: references/init-and-login.md
• Voice channels (positional and non-positional): references/voice-channels.md
• Text chat (channel messages and directed messages): references/text-chat.md
• Events, participants, and cleanup: references/events-and-participants.md
• Troubleshooting and platform notes: references/troubleshooting.md

Initialization Order (Do Not Skip Steps)

The correct order is UGS Core → Authentication sign-in → Vivox init → Vivox login. Skipping or reordering these fails silently or throws obscure errors.

using Unity.Services.Core;
using Unity.Services.Authentication;
using Unity.Services.Vivox;

async void Start()
{
    await UnityServices.InitializeAsync();
    await AuthenticationService.Instance.SignInAnonymouslyAsync();
    await VivoxService.Instance.InitializeAsync();
    // subscribe to events (see table below) BEFORE calling LoginAsync
    await VivoxService.Instance.LoginAsync(new LoginOptions { DisplayName = "Bob" });
}

• Calling VivoxService.Instance.InitializeAsync() twice throws 5041 VxErrorAlreadyInitialized. Guard against re-init on scene reload.
• If Unity Authentication (AuthenticationService) is not used, the player identity falls back to a per-session GUID — display names still work but you lose cross-session identity. See references/init-and-login.md for the Vivox Access Token (VAT) alternative.

Joining Channels

Vivox has three join methods, one per channel type. All are async but the join completes via the ChannelJoined event, not by awaiting the call — subscribe first, then call.

ChatCapability values: TextOnly, AudioOnly, TextAndAudio.

Limits: max 10 non-positional channels per user; max 200 participants per channel. Exceeding either fails with 20502 VxXmppServerErrorServiceUnavailable. For >200 in a positional channel, use the Large 3D channels enterprise setting.

Leave with VivoxService.Instance.LeaveChannelAsync(channelName) or LeaveAllChannelsAsync(). See references/voice-channels.md for Channel3DProperties fields and mic-permission handling on Android/iOS.

Text Messaging

Channel messages (broadcast to all participants of a channel with TextOnly or TextAndAudio):

• Send: VivoxService.Instance.SendChannelTextMessageAsync(string channelName, string message)
• Receive: subscribe to VivoxService.Instance.ChannelMessageReceived (Action<VivoxMessage>)

Directed messages (peer-to-peer, no channel required):

• Send: VivoxService.Instance.SendDirectTextMessageAsync(string playerId, string message)
• Receive: subscribe to VivoxService.Instance.DirectedMessageReceived (Action<VivoxMessage>)

Common hallucination: the send method is SendDirectTextMessageAsync — not SendDirectedTextMessageAsync. The event, however, is DirectedMessageReceived. Note the asymmetry.

VivoxMessage fields: ChannelName (null for directed), SenderDisplayName, SenderPlayerId, MessageText, ReceivedTime, Language, FromSelf, MessageId.

Edit/delete APIs (EditChannelTextMessageAsync, DeleteChannelTextMessageAsync, EditDirectTextMessageAsync, DeleteDirectTextMessageAsync) and history (GetChannelTextMessageHistoryAsync, GetDirectTextMessageHistoryAsync) are covered in references/text-chat.md. Chat history retention is 7 days by default.

Required Event Subscriptions

Subscribe to events before the corresponding async call. LoggedIn may fire immediately for reconnects; ChannelJoined fires as the join completes.

Always unsubscribe in OnDestroy / OnDisable. VivoxService.Instance is a persistent singleton — event handlers on destroyed MonoBehaviours will double-fire and NRE on scene reload.

Per-participant events (ParticipantMuteStateChanged, ParticipantSpeechDetected, ParticipantAudioEnergyChanged) live on the VivoxParticipant instance you receive from ParticipantAddedToChannel — not on VivoxService.Instance. See references/events-and-participants.md.

Access Tokens (Brief)

The default path uses UGS Authentication — Vivox mints access tokens automatically from your UGS project once AuthenticationService.Instance.SignInAnonymouslyAsync() (or another sign-in method) has completed. No manual token code is required for standard flows.

Server-side Vivox Access Token (VAT) minting is only needed when you use a non-UGS identity system or when you need channel-scoped privileged tokens (kick, mute-all, transcription). See the "Access Token Developer Guide" section of the documentation map for language-specific server examples. Do not embed HMAC signing keys in the client.

Validation

After writing code that uses this package:

1. Verify the project compiles without errors and that using Unity.Services.Vivox; resolves.
2. Confirm init order: UnityServices.InitializeAsync → AuthenticationService.Instance.SignInAnonymouslyAsync → VivoxService.Instance.InitializeAsync → VivoxService.Instance.LoginAsync.
3. No v4 legacy patterns: no Client.Instance, no AccountId, no ChannelId, no ILoginSession, no IChannelSession. All access goes through VivoxService.Instance.
4. All events consumed by the code are subscribed before the async call that triggers them, and are unsubscribed in OnDestroy.
5. Channel join code does not await the join call as if it completes join — it subscribes to ChannelJoined and reacts there.
6. Directed message send uses SendDirectTextMessageAsync (NOT SendDirectedTextMessageAsync). Directed message receive uses DirectedMessageReceived.
7. Android builds request RECORD_AUDIO at runtime before joining an audio channel; iOS builds have NSMicrophoneUsageDescription in the plist.
8. No HMAC signing keys or Vivox SECRET/APP_ID are embedded in client code — VAT-based flows are documented but delegated to a server.