Retell AI Voice Agent: Setup Guide

Retell turns inbound calls into qualified leads without burning your team's time. This guide walks you through the complete setup: account configuration, voice selection, tone calibration, qualification script architecture, and n8n webhook integration for automatic lead routing.

You'll have a production-ready voice agent that screens leads, books consultations, and feeds clean data into your CRM CRMCustomer Relationship Management software. The system of record for contacts, deals, and client communication. Examples: HubSpot, Salesforce, Pipedrive..

Go to retellai.com and create an account. Skip the trial tier. Go straight to the Growth plan ($99/month) if you're processing more than 100 calls monthly. The free tier caps at 10 calls and lacks webhook webhookClick to read the full definition in our AI & Automation Glossary. access.

After signup, navigate to Settings > API APIApplication Programming Interface. The connection point that lets two pieces of software exchange data. How n8n talks to your CRM. Keys. Generate a new API key and store it in your password manager. You'll need this for n8n integration in Step 5.

Set your business hours in Settings > Availability. Configure:

• Operating hours (e.g., Monday-Friday 8am-6pm EST)
• Holiday schedule
• Overflow behavior (voicemail, callback request, or transfer to human)

Add your business phone number under Phone Numbers > Add Number. Retell supports both toll-free and local numbers. Port an existing number or provision a new one. Porting takes 3-5 business days.

Navigate to Agents > Create New Agent > Voice Settings.

Retell offers 47 voice options across three categories:

Professional Voices (law, accounting, consulting):

• Marcus: Male, 40s, authoritative but approachable. Best for B2B professional services.
• Elena: Female, 30s, confident and warm. Works well for client-facing roles.
• David: Male, 50s, experienced advisor tone. Ideal for wealth management or legal.

Conversational Voices (marketing, creative services):

• Sophia: Female, 20s, energetic and friendly. High engagement for younger audiences.
• Jake: Male, 30s, casual but competent. Good for tech or startup clients.

Specialized Voices (medical, technical):

• Dr. Chen: Female, 40s, clinical precision with empathy. Healthcare-specific.
• Alex: Non-binary, 30s, neutral and clear. Works across industries.

Test each voice with your actual qualification script. Click the voice name, then "Test with Custom Script." Paste your script and listen to the full interaction. Pay attention to:

• Pronunciation of industry terms (EBITDA, voir dire, amortization)
• Natural pauses between questions
• Handling of interruptions

For professional services, Marcus or Elena consistently outperform other options in A/B tests. Marcus converts 18% higher for legal and accounting. Elena performs 22% better for consulting and advisory.

Under Voice Settings, adjust these parameters:

Speaking Rate: Set to 1.1x for professional services. Default 1.0x feels sluggish. Anything above 1.2x sounds rushed.

Pitch Variance: Set to "Medium" (0.5 on the slider). Low variance sounds robotic. High variance sounds unprofessional.

Pause Duration: Set to 0.8 seconds between questions. This gives leads time to think without creating awkward silence.

Emphasis Markers: Use SSML tags in your script to control emphasis:

We specialize in <emphasis level="strong">tax planning</emphasis> for high-net-worth individuals.

Pronunciation Overrides: Add custom pronunciations under Settings > Pronunciation Dictionary:

• EBITDA: "ee-bit-dah"
• Voir dire: "vwahr deer"
• Amortization: "am-or-tih-zay-shun"

Test these settings with a 5-minute sample call. Record it, then play it back at 1.5x speed. If it still sounds natural at 1.5x, your pacing is correct.

Your script needs three sections: Opening, Qualification, and Routing.

Opening (15 seconds):

Hi, this is [Agent Name] with [Firm Name]. I'm calling about your inquiry regarding [service]. Do you have 3-4 minutes to discuss your needs?

[If yes, continue. If no, offer callback.]

Great. I'll ask a few quick questions to make sure we connect you with the right specialist.

Qualification Questions (2-3 minutes):

Ask these five questions in order:

1. Urgency: "What's driving your timeline? Are you looking to start within the next 30 days, 60 days, or just exploring options?"

2. Budget Awareness: "Have you allocated a budget for this project? We typically see engagements in the $X-$Y range for [service type]."

3. Decision Authority: "Who else is involved in the decision-making process? Will you be the primary point of contact?"

4. Pain Point: "What's the biggest challenge you're trying to solve? Walk me through what's not working right now."

5. Fit Check: "Have you worked with a [lawyer/accountant/consultant] on this type of issue before? What worked or didn't work about that experience?"

Routing Logic (30 seconds):

Based on what you've shared, I think [Partner Name] would be the best fit. They specialize in [specific area] and have worked with [similar client type].

I can get you on their calendar this week. Does [Day] at [Time] or [Day] at [Time] work better?

[Book appointment]

Perfect. You'll receive a confirmation email in the next few minutes with a calendar invite and a brief intake form. [Partner Name] will review that before your call.

Disqualification Script:

I appreciate you sharing that context. Based on what you've described, we may not be the best fit right now because [specific reason].

I'd recommend [alternative resource or referral]. Would you like me to send you their contact information?

Save this script in the Agent Configuration panel. Use the "Variables" feature to personalize:

• {{lead_name}}
• {{service_inquired}}
• {{referral_source}}

This integration sends qualified lead data from Retell into your CRM and triggers follow-up workflows.

In Retell:

1. Go to Agents > [Your Agent] > Integrations > Webhooks
2. Click "Add Webhook Endpoint"
3. Set Trigger to "Call Completed"
4. Leave the URL field blank for now (you'll add this after creating the n8n workflow)

In n8n:

1. Create a new workflow
2. Add a Webhook node as the trigger
3. Set Method to POST
4. Set Path to /retell-lead-intake
5. Copy the Production URL (looks like: https://your-instance.app.n8n.cloud/webhook/retell-lead-intake)
6. Go back to Retell and paste this URL into the Webhook Endpoint field

Configure the n8n workflow:

Add these nodes in sequence:

Node 1: Webhook (trigger)

Node 2: Function (parse Retell data)

const retellData = $input.item.json;

return {
  json: {
    leadName: retellData.lead_name,
    phone: retellData.phone_number,
    email: retellData.email,
    serviceInquired: retellData.service_type,
    urgency: retellData.custom_fields.urgency,
    budget: retellData.custom_fields.budget,
    decisionMaker: retellData.custom_fields.decision_authority,
    painPoint: retellData.custom_fields.pain_point,
    qualified: retellData.custom_fields.qualification_status,
    callRecording: retellData.recording_url,
    transcript: retellData.transcript
  }
};

Node 3: IF (qualification router)

• Condition: {{$json.qualified}} equals "yes"
• True branch: Create CRM contact + Send Slack notification + Book calendar
• False branch: Add to nurture list + Send rejection email

Node 4a (True): HTTP Request (create CRM contact)

• Method: POST
• URL: Your CRM's API endpoint
• Body: Map fields from Node 2 output

Node 4b (True): Slack (notify sales team)

• Message: "New qualified lead: {{$json.leadName}} - {{$json.serviceInquired}} - Urgency: {{$json.urgency}}"
• Channel: #sales-leads

Node 4c (True): Calendly (book appointment)

• Use Calendly API to create event
• Send confirmation email with intake form link

Node 5a (False): HTTP Request (add to nurture list)

• Add contact to "Unqualified - Nurture" segment in your email platform

Node 5b (False): Send Email (rejection with resources)

• Template: Thank you + alternative resources + "check back in 6 months"

Test the workflow by making a test call to your Retell number. Verify that:

• Webhook fires within 10 seconds of call completion
• Data appears correctly in your CRM
• Slack notification includes all key fields
• Calendar invite sends to the lead

Set up these monitoring dashboards:

Retell Dashboard (daily check):

• Call volume by hour
• Average call duration (target: 3-4 minutes)
• Qualification rate (target: 35-45% for cold inbound)
• Drop-off points in script

n8n Execution Log (weekly review):

• Webhook success rate (target: 99%+)
• Failed executions and error types
• Average processing time (target: under 2 seconds)

CRM Reports (monthly analysis):

• Lead source: Retell voice vs. other channels
• Qualification accuracy (how many "qualified" leads actually close)
• Revenue per Retell lead vs. other sources

Adjust your script based on drop-off analysis. If 40% of leads hang up at the budget question, soften the language or move it later in the conversation.

Update voice settings quarterly. Test new voices against your current baseline. Run A/B tests with 100 calls minimum per variant.

Your Retell agent is now live and feeding qualified leads directly into your sales pipeline. The average firm sees first appointments booked within 48 hours of going live.

How do I set up Retell AI for lead qualification? Six steps: (1) Create a Retell account and generate an API key. (2) Purchase a phone number. (3) Select your voice - Marcus or Elena consistently outperform other options for professional services. (4) Build a qualification script with three sections: Opening, Qualification Questions (5 specific questions), and Routing Logic. (5) Connect n8n via webhook. (6) Monitor weekly using Retell dashboard metrics.

How does Retell AI compare to Bland and Synthflow? Retell AI has the lowest call setup latency (under 800ms), the cleanest n8n webhook integration, and the most predictable per-minute pricing ($0.07-0.15/min). Bland offers more advanced call branching for complex scripts. Synthflow offers the most accessible visual builder for non-technical staff. Retell is the recommended starting platform for professional services firms.

What questions should my Retell AI voice agent ask? Five questions in order: (1) Urgency: timeline and readiness. (2) Budget awareness: allocated budget. (3) Decision authority: who else is involved. (4) Pain point: the specific problem they're trying to solve. (5) Fit check: prior experience with similar services. Collect urgency and budget early; pain point and fit check after rapport is established.

What is Retell AI's pricing? Retell charges $0.07-0.15/minute (model tier dependent). The Growth plan ($99/month base) provides webhook access and CRM integration for production use. At 500 calls/month averaging 3 minutes each, Retell costs approximately $105-225/month, compared to an intake coordinator at $3,000-4,500/month in fully loaded cost.