Build a Voice Agent

Step-by-step walkthrough for creating a voice-only agent. Inbound, outbound, or bidirectional calls via Twilio, Telnyx, SIP Trunk, or WhatsApp Calls. The wizard has 6 steps in this order: Voice Agent Settings, Appearance, Knowledge Base, Tickets & Leads, Integrations & Tools, Deployment.

Voice agents handle phone calls only. No chat. To enter, click Create Agent on the dashboard topbar, then Voice Agent in the picker. The wizard opens at Step 1: Voice Agent Settings.

Pre-flight

Before you start, have these ready:

• A name for your agent.
• A brief description of the call’s purpose.
• A telephony provider account with at least one provisioned number (Twilio, Telnyx, SIP Trunk, or WhatsApp Calls). You’ll plug it in at Step 6.
• Any knowledge sources (files, FAQs, URLs) for the agent to reference during calls.

The wizard runs at /{lang}/create/voice/{step}. The first step is voice-settings.

Step-by-step

1. Step 1: Voice Agent Settings

   Pick a voice from the Voice Picker (50+ Wittify voices, search and filter), set the language, write the Core Instructions (voice prompt), tune Speaking Speed, Voice Temperature, and 7 advanced fields (Min Silence Duration, End Call on Silence, Max Call Duration, Min Speech Duration, Widget Popup Delay, Ask for Feedback toggle), and pick a Background Sound (5 ambient options with volume).

   The Agent Name field lives here (voice-only skips Text Agent Settings entirely, so the name moves into this step).

   Required to advance: agent name, Core Instructions (max 2,500 characters).

   Full step reference →

2. Step 2: Appearance

   Brand the voice widget: colors, logo, avatar, launcher icon, position, voice screen text per language, post-call ratings, font.

   Voice variants don’t have Chat Screen Text fields. The voice screen replaces them: greeting, connecting message, in-call placeholder, end-call message, plus voice-specific labels.

   Full step reference →

3. Step 3: Knowledge Base

   Upload files, add FAQs, crawl URLs. Same shape as the Text variant. The agent uses these during calls to answer questions.

   This step is optional.

   Full step reference →

4. Step 4: Tickets & Leads

   Configure data collection during calls. The Voice Agent tab is the active one (the Text Agent tab is hidden for voice-only).

   This step is optional.

   Full step reference →

5. Step 5: Integrations & Tools

   Same as Text variant: marketplace, MCP, agent tools, custom API tools, webhooks.

   This step is optional.

   Full step reference →

6. Step 6: Deployment

   Two tabs (Social is hidden for voice-only): Website (embed for the voice widget on a webpage if you want web-initiated calls), Telephony (4 provider cards), plus the Agent Status card to Activate.

   Full step reference →

What the Voice wizard hides (compared to Hybrid)

Hybrid is the superset. Voice trims out:

• Text Agent Settings (no chat-only step). The Agent Name field moves into Voice Agent Settings instead.
• The chat toggle in the live preview pane. The widget preview always shows the voice view.
• Chat Screen Text fields in Appearance.
• The Social deployment tab (no WhatsApp / Messenger / Instagram / X / Telegram chat).
• The Text tab in Tickets & Leads.

Telephony providers

The Deployment step gives you four provider cards in a 2-column grid:

Provider	Direction	Credentials
Twilio	Inbound / Outbound / Bidirectional	Account SID, Auth Token
Telnyx	Inbound / Outbound / Bidirectional	API Key
SIP Trunk	Inbound / Outbound / Bidirectional	None, system generates a SIP URI you point your PBX at
WhatsApp Calls	Inbound only (today)	Phone Number ID, Access Token

Each provider supports up to 10 phone numbers or extensions with type phone or extension.

Test before you ship

Two test surfaces:

1. In the wizard, the right-side preview pane shows the voice widget. Click the call button to dial the agent. The first call requires microphone permission for app.wittify.ai.
2. After the first save, the Test Your Agent button is in the topbar of every Manage Agent page. Same flow, but on a real Manage Agent surface. Read more →

Activate

When all steps you care about are saved, go to Step 6: Deployment and look at the Agent Status card. Click Activate Agent (green, check icon). The agent goes online and starts answering calls on every connected provider line. Toast: Agent activated.

Inbound and bidirectional calls start answering the moment a call lands on a connected number. Outbound campaigns are scheduled separately, see Outbound Voice Campaigns.

Common questions

My voice agent doesn't speak when I test the call.

Three checks: (1) you’ve selected a voice in Step 1’s Voice Picker, (2) the Core Instructions are non-empty, (3) microphone permission is granted to app.wittify.ai. The widget shows a “Tap to talk” hint when waiting for input.

The agent talks too fast.

Tune Speaking Speed in Step 1’s Advanced Voice Settings. Default is 1.0, lower it to 0.85-0.9 for slower speech. The valid range is 0.5 to 2.0.

Calls connect but the agent never picks up.

Check Step 6’s Agent Status card, the agent is Draft until you click Activate. Activate, place a test call again.

Twilio rejected my caller ID.

Twilio requires verified caller IDs for outbound. In your Twilio console, verify the number you’re using as caller ID, then try again from the wizard.

Can I record calls?

Voice calls are recorded by default for transcription and AI summary. Recordings are accessible in Voice Conversations after each call ends.

Why is the Social deployment tab missing?

Voice-only agents can’t take chat traffic. The Social tab is hidden because there’s nothing to wire. If you ever need chat too, delete this agent and create a Hybrid one.

Next

Open Step 1

Start at Voice Agent Settings.

See Voice Conversations

Where calls and recordings live.