Client API Keys

By default, all agents use your agency’s voice provider API keys. BuildVoiceAI also supports per-client API keys, allowing individual clients to connect their own Retell, Vapi, or Bland accounts. When a client has their own keys configured, their agents use those keys instead of the agency defaults.

How It Works

BuildVoiceAI follows a simple fallback chain when determining which API key to use for a client’s agent:

Client-level key — If the client has their own API key set for the provider, it is used
Agency-level key — If no client-level key is set, the agency’s default key is used

This fallback is automatic and requires no additional configuration on individual agents. All agents assigned to a client will use whatever key is resolved through this chain.

When to Use Client API Keys

There are several scenarios where per-client API keys are useful:

Client manages their own provider account — The client has an existing relationship with Retell, Vapi, or Bland and wants to use their own account for billing and rate limits
Usage isolation — The client wants their voice AI usage tracked and billed directly by the provider rather than through your agency
Rate limit separation — High-volume clients may need their own API rate limits independent of your other clients
Compliance requirements — The client’s organization requires that API keys and data processing stay within their own accounts

Setting Client API Keys

To configure API keys for a specific client:

Navigate to Clients and select the client
Open the API Keys or Settings tab
Enter the API key for the relevant provider:
- Retell API Key
- Vapi API Key
- Bland API Key
Click Save

Client API keys form with fields for Retell, Vapi, and Bland keys

Enter per-client API keys to override agency defaults.

You only need to set keys for the providers the client actually uses. If a client only has Retell agents, you do not need to provide Vapi or Bland keys.

Verifying Client Keys

After entering a client API key, it is a good practice to verify it works correctly:

Create or select a test agent assigned to that client
Make a test call with the agent
Confirm the call connects and functions properly

If the key is invalid or has insufficient permissions, the test call will fail with a provider error.

⚠️

If a client’s API key becomes invalid (expired, revoked, or rate-limited), their agents will fail to make and receive calls. BuildVoiceAI does not automatically fall back to agency keys when a client key is present but invalid.

Removing Client API Keys

To revert a client back to using your agency keys:

Navigate to the client’s API Keys settings
Clear the API key field for the relevant provider
Click Save

The client’s agents will immediately start using the agency-level key for that provider on the next call.

Security Considerations

Client keys are stored securely and encrypted at rest. They are never exposed in the client portal or API responses.
Only agency admins can view and manage client API keys. Client portal users, regardless of their permissions, cannot see or modify API keys.
Treat API keys carefully when clients share them with you. Use secure channels (not email) to receive keys from clients whenever possible.

💡

If a client wants to manage their own API keys, consider enabling the manage_integrations permission and guiding them to enter their keys through the client portal settings. This avoids the need for them to share keys with you directly.

Impact on Billing

When a client uses their own provider API key, the provider bills the client directly for usage. Your agency still sees the call activity and analytics in BuildVoiceAI, but the per-minute provider costs are charged to the client’s own provider account rather than yours.

If you are also billing the client through BuildVoiceAI’s billing system, you may want to adjust your rates to account for the fact that you are no longer covering the provider costs.