Feature Request: tts_aligned_transcripts for Node SDK

[stewarteaton]

Looking for tts_aligned_transcripts feature enabled with Node.js SDK

Problem

When using LiveKit voice agents with Node.js, AI transcripts consistently arrive delayed relative to audio playback in staged/production environments. This makes it difficult to sync transcript UI with TTS audio.

Locally the timing is acceptable, but once deployed the transcript lag becomes noticeable.

LiveKit already provides tts_aligned_transcripts in the Python SDK:
https://docs.livekit.io/agents/multimodality/text/#tts-aligned-transcriptions

However, this capability does not appear to be available in the Node.js agents SDK.

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Proposed solution

Expose tts_aligned_transcripts in the Node.js agents SDK, matching the Python feature.

Ideally this would provide:

• Word or sentence timestamps aligned to TTS audio
• Or transcript chunks emitted in playback-synchronized order
• Available through session history or agent events

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Why this matters

This would enable:

• Accurate real-time transcript synced to audio
• UX improvements

Without alignment, transcripts feel delayed and less trustworthy to users.

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Additional context

I’m using LiveKit agents with ElevenLabs TTS and LiveKit inference. The issue is most noticeable when running agents in staged/production environments.

I originally asked about this in the LiveKit Slack and was advised to raise this here as an enhancement request.

[toubatbrian]

Hey @stewarteaton, we are working on this feature now: #990~

[stewarteaton]

Hey @stewarteaton, we are working on this feature now: #990~

Thanks so much! Any idea when to expect the merge?