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POST
/
v4
/
project
/
{projectID}
/
session
Start session (with traffic split)
curl --request POST \
  --url https://general-runtime.voiceflow.com/v4/project/{projectID}/session \
  --header 'Content-Type: application/json' \
  --header 'authorization: <api-key>' \
  --data '
{
  "userID": "<string>"
}
'
{
  "sessionKey": "<string>"
}

Documentation Index

Fetch the complete documentation index at: https://docs.voiceflow.com/llms.txt

Use this file to discover all available pages before exploring further.

The start session endpoint creates a new conversation session and returns a sessionKey. Use this key as your authentication credential when calling the Interact and Interact (non-stream) endpoints. This start session endpoint respects the traffic split setup in your project. If you’d like to send traffic to a specific environment, use Start session (specific environment) instead.

Authorizations

​
authorization
string
header
required

Voiceflow API key

Path Parameters

​
projectID
string
required

The ID of the target Voiceflow project. You can find it in the settings for your agent.

Body

application/json
​
userID
string
required

Unique ID for the user. If a session already exists for this user, the existing session will end and a new session will be created with a new session key.

Required string length: 1 - 256

Response

200 - application/json
​
sessionKey
string
required

A session-scoped authentication key. Pass this as the authorization header when calling the interact endpoints.