Create Server Credential
Create a credential for authenticating requests to your custom endpoints (tools, webhooks, or custom LLM/TTS providers). The credential is synced to the voice engine and can be referenced by assistantcredential_ids.
Endpoint
Request Body
Credential name (e.g., “My OpenAI Key”, “Production Webhook Auth”)
Authentication type:
bearer_token, oauth2_client_credentials, or hmacOptional description
Public (non-secret) configuration. Required fields depend on auth_type.
- For
oauth2_client_credentials:token_urlandclient_id - For
hmac:algorithm(e.g.,sha256)
Secret values (encrypted at rest, never returned in full).
- For
bearer_token:token - For
oauth2_client_credentials:client_secret - For
hmac:secret_key
Example Request
Bearer Token
OAuth2 Client Credentials
HMAC
Response
vapi_credential_id is the UUID assigned by the voice engine — use this in assistant credential_ids.

