Conversations That Feel Human
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VoIP Answering Service That Works With Your Existing Phone System
Retell connects to your VoIP setup over SIP trunking, answers every call 24/7, handles routine ones itself, and brings in your team when a caller needs one.
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How it works
A Smarter Way to Answer Business Calls
01
Call arrives on your existing number
02
AI answers instantly, no hold
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Answers, books, or collects details
04
Warm transfer to a human when needed
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Summary, recording and CRM sync
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AI vs traditional answering service
Retell VS. A Traditional VoIP Answering Service
Traditional Services
Retell
Contact SalesHours
Business hours, or a paid add-on for nights and weekends
Every call answered 24/7, including nights, weekends and holidays
What You Pay For
Per minute and per call, with hold time and monthly retainers on top
Usage-based from $0.07/min, $10 in free credits to start
Wait Time
Callers hold for the next free operator
Answered on the first ring, no queue
Busy Periods
Limited by how many operators are staffed; callers wait or drop
20 concurrent calls included, higher on Enterprise
Consistency
Varies with whoever picks up
The same answer quality on every call
Languages
Usually English, more languages cost extra
More than one language handled the same way
Handing Off To You
Takes a message or transfers with little context
Warm transfer with the full transcript and CRM record attached
Setup
Requires porting your number or building new call forwarding rules before anything works
Keep your VoIP number, connect over SIP trunking, and go live without changing carriers
Your Tools
Runs separately from your VoIP system, so calls and data live in two different places
Connects directly to Twilio, Telnyx or Vonage over SIP trunking, so it works inside the setup you already have
Compliance
Retell VS. A Traditional VoIP Answering Service
Trust is essential when adopting an AI receptionist. Retell AI is built with enterprise-grade security, ensuring every call is protected while meeting the strictest industry standards.
SOC 2 Type II
Patient call data runs on SOC 2 Type II certified infrastructure, clearing most clinic and hospital security reviews.
HIPAA
HIPAA-ready with a self-service BAA portal, and downstream voice and model sub-processors are covered under BAAs too.
GDPR
Patient data is handled in line with GDPR, covering consent, access rights, and processing records for international patients.
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PII Redaction
Social Security numbers, card details, and patient identifiers are redacted from transcripts automatically before storage.
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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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
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.
