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Start an interactive avatar session

post
https://developers.synthesia.io/api/interactive-avatars/sessions

Start an interactive avatar session.

  • Each running session counts toward your plan's concurrent-session limit until it ends.
  • Only sessions started through this API count toward the limit.
  • Over the limit, the request fails with 429 and the concurrency_limit_exceeded problem
    type; its detail states your plan's limit and how many sessions are running.
PlanConcurrent sessions
Freemium1
All paid plans100
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Body Params

A session runs in your own LiveKit room: the avatar joins it as a participant. Synthesia
does not host the room, mint LiveKit tokens, or carry the media.

avatarIds
array of strings
required
length ≥ 1

The interactive avatars to join the session — e.g. the id returned by POST /api/interactive-avatars/avatars once its status is completed.

Avatar Ids*

The avatar id, prefixed av_….

string
required
length ≥ 1

The WebSocket URL (wss://…) of your LiveKit room the avatar joins.

string
required
length ≥ 1

A LiveKit access token you mint for the avatar's participant in that room. If you retry a failed request, reuse the same livekitUrl and livekitToken.

Headers
string
enum
Defaults to application/json

Generated from available response content types

Allowed:
Responses

Updated about 4 hours ago

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Response
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application/json
application/problem+json

Updated about 4 hours ago

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