Conversations That Feel Human
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The Problem
Why VoIP Businesses Are Moving to an AI Answering Service
A traditional answering service usually means routing your calls away from the VoIP system you already pay for and depend on. Retell plugs into your existing VoIP provider over SIP trunking, so calls still flow through Twilio, Telnyx or Vonage and you keep your number, your call flows and your reporting.
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Comparison
Retell VS. A Traditional VoIP Answering Service
Hours
What You Pay For
Wait Time
Busy Periods
Consistency
Languages
Handing Off To You
Setup
Your Tools
Traditional Answering Service
Business hours, or a paid add-on for nights and weekends
Per minute and per call, with hold time and monthly retainers on top
Callers hold for the next free operator
Limited by how many operators are staffed; callers wait or drop
Varies with whoever picks up
Usually English, more languages cost extra
Takes a message or transfers with little context
Requires porting your number or building new call forwarding rules before anything works
Runs separately from your VoIP system, so calls and data live in two different places
Every call answered 24/7, including nights, weekends and holidays
Usage-based from $0.07/min, $10 in free credits to start
Answered on the first ring, no queue
20 concurrent calls included, higher on Enterprise
The same answer quality on every call
More than one language handled the same way
Warm transfer with the full transcript and CRM record attached
Keep your VoIP number, connect over SIP trunking, and go live without changing carriers
Connects directly to Twilio, Telnyx or Vonage over SIP trunking, so it works inside the setup you already have
Cost per minute
$0.07-$0.31/min
LLM: gpt-5
$0.040/min
TTS: platform
$0.015/min
Voice Engine
$0.055/min
Background speech removal
$0.005/min
Safety Guardrails
$0.005/min
Buyer’s Guide
How to Choose a VoIP Answering Service
$0.07-$0.31 Per Minute
You pay for real call time, nothing else.
$10 in Free Credits
Try it before you pay anything.
No Monthly Retainers
Nothing extra for nights, weekends or busy periods.
Lower Bills Overall
Routine calls clear on their own, so spend drops.
Capabilities
What Our Agent Does on a Call
Sends Every Caller to The Right Place:
It works out why someone is calling and routes them to sales, support or billing, with no phone menu to sit through.
Routing can follow your CRM, so callers reach their account owner or region instead of a general queue.
When a person is needed, the agent warm-transfers them over your existing lines, along with the full conversation and CRM record.
Answers from Your Own Knowledge Base:
It stays in sync with your knowledge base, so callers hear current answers about hours, services and pricing.
It can look up a caller's record mid-call and tailor what it says.
It can pull from your CRM, ticketing or billing tools over secure webhooks while the call is live.
Setup
Live in Four Steps
Step 1
Build
Set the agent up in a no-code dashboard or with the API, and point it at your website and FAQs.
Step 2
Test
Run it against the calls you really get and confirm it answers well and hands off cleanly.
Step 3
Deploy
Connect your existing VoIP provider, Twilio, Telnyx or Vonage, over SIP trunking and keep your current number, then go live on voice, SMS and chat.
Step 4
Monitor
Track resolution and transfer rates and caller sentiment from the dashboard, and refine over time.
Value
Why Businesses Choose Retell
A Clean Handoff to Your Team
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Reporting You Can Act On
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Built for Sensitive Data
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- Hubspot
- Twilio
- Vonage
- Go High Level
- n8n
- Zapier
- Salesforce
- Hubspot
- Twillio
- Vonage
- Go High Level
- 8n8
- Zapier
- Salesforce
- Avaya
- Genesys
- Five9
- Amazon Connect
- Telnyx
- Make
- Cal.com
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- Avaya
- Genesys
- Five9
- Amazon Connect
- Telnyx
- Make
- Cal.com
Overview
Built to scale with you
From quick-start simplicity to enterprise-grade security, compliance, and support. Retell meets you wherever you are.
Put Your Business Answering Service to Work Today
Start from a template, sync your knowledge base, and connect your line or take a new number. Try it on your real calls, then go live on voice, SMS and chat.
FAQ
Common Questions
Which VoIP providers does Retell connect to?
Retell connects to your existing VoIP setup through SIP trunking, with direct support for Twilio, Telnyx and Vonage. If you already route calls through one of these providers, Retell plugs into that setup instead of asking you to switch carriers or take a new number.
How does the SIP trunking setup work?
SIP trunking is how your VoIP system already connects calls to the public phone network, so Retell uses that same connection. You point your provider, Twilio, Telnyx or Vonage, to route calls to Retell over a SIP trunk. That gives Retell a live path to answer and hand off calls without new hardware or any change to how your number works.
Can I keep my existing VoIP phone number?
Yes. Connecting over SIP trunking means your number stays with your current carrier. Retell answers on that number without a port, so there is no downtime and nothing to update anywhere else.
How much does Retell cost?
Retell is usage-based starting at $0.07 per minute, with $10 in free credits to start so you can test it on real calls before committing.
Does Retell support more than one language?
Yes. Retell handles multiple languages with the same call quality, so callers get answered in the language they call in.
How fast can I get a VoIP answering service live?
Most teams start from a template, sync their knowledge base, and connect their VoIP provider over SIP trunking the same day. There is no lengthy number port or operator training to wait on.
What happens when a caller needs a real person?
Retell warm-transfers the call to your team along with the full transcript and any CRM record, so whoever picks up already has the context instead of starting from a blank message.
