Platform
Vapi voice agents wired into your CRM
Vapi is the more developer-oriented of the two main voice platforms. That flexibility is worth having when the agent needs to do more than talk.
Quick answer
What is Vapi and what is it used for?
Vapi is a platform for building programmable AI voice agents. It handles speech recognition, language model orchestration, speech synthesis and telephony, and exposes function calling so an agent can read and write external systems — checking calendars, creating CRM records or booking appointments during the call.
The problem
What this actually fixes
You need a voice agent that acts on live data rather than reading a script.
Off-the-shelf voice tools cannot express the logic your calls require.
Existing agents take messages instead of completing the booking.
Call transcripts live in a separate tool and never reach the CRM.
Telephony routing needs are more complex than a simple inbound number.
Scope
What's included
Every engagement is scoped to what you actually need. This is the full deliverable list.
Deliverable 01
Agent development
Conversation design, prompt engineering and behavioural boundaries built for the specific job.
Deliverable 02
Function calling
Live integration so the agent can query availability, create contacts and book appointments mid-conversation.
Deliverable 03
GoHighLevel integration
Contacts, transcripts, recordings and outcomes written to the CRM so the call is on the record.
Deliverable 04
Telephony configuration
Numbers, inbound and outbound routing, warm transfer and failover.
Deliverable 05
Voice and latency tuning
Voice selection and response timing tuned so the conversation feels natural rather than delayed.
Deliverable 06
Monitoring and cost control
Usage tracked and call outcomes reviewed, since voice is billed per minute and costs scale with volume.
How it works
From first call to running system
- Step
Define the job and boundaries
What the agent handles, what it escalates, and what it may never claim.
- Step
Build the agent
Prompt, conversation flow and functions built and connected.
- Step
Connect telephony and CRM
Numbers provisioned, routing configured, CRM writes wired and tested.
- Step
Test and tune
Exercised against realistic call conditions, then piloted on limited traffic.
Platform choice matters less than you think
Teams evaluating voice platforms often spend considerable time comparing Vapi and Retell feature by feature.
For most builds, that comparison is less consequential than it appears. Both handle conversation, both support function calling, both produce agents that callers accept. The difference in outcome between them is smaller than the difference between a well-designed conversation and a poorly designed one on either platform.
Where the choice genuinely matters is at the edges — unusual telephony requirements, complex chained function calls, specific latency targets. We assess that during scoping. If your build does not have those constraints, pick either and spend the saved time on the script.
Stack
What this connects to
- VapiProgrammable voice agents with low-latency speech and function calling.
- TwilioPhone numbers, SMS delivery and call routing infrastructure.
- GoHighLevelCRM, pipelines, funnels, calendars and workflows — the system of record.
- OpenAILanguage models for qualification, summarisation and reply drafting.
- Webhooks & REST APIsCustom integrations for anything without a native connector.
Questions
Vapi Integration — common questions
How is Vapi different from Retell?
Vapi is generally the more developer-oriented and configurable of the two, with more control over telephony and function calling. Retell is often faster to get a good result from on straightforward conversational agents. Both are capable; we choose on what the specific agent needs to do rather than by default.
Can a Vapi agent book directly into GoHighLevel?
Yes, through function calling. The agent queries live availability during the conversation and writes the booking back, so it never offers a slot that has just been taken. That round trip is what makes it a booking agent rather than a message taker.
What does it cost to run?
Usage-based, billed per minute across the voice platform, telephony and language model. It scales with call volume rather than being a flat fee, so we model expected monthly cost against your actual call numbers during scoping.
Can it make outbound calls?
Yes, triggered by CRM events or worked through a list. Outbound carries consent and calling-window obligations that inbound does not, so those get built into the logic rather than handled operationally.
What happens to call recordings and transcripts?
They are written to the contact record in GoHighLevel, so the conversation is visible alongside every other interaction. Recording consent requirements vary by jurisdiction and are configured accordingly.
Related services
AI voice agents that hold a real conversation
An AI voice agent is software that conducts a spoken phone conversation in natural language. It understands what a caller says, responds in real time, follows the rules it was given, and takes actions such as booking an appointment, creating a CRM record or transferring to a human when the conversation requires one.
Retell AI agents built for conversation quality
Retell AI is a platform for building conversational voice agents that handle inbound and outbound calls. It manages speech recognition, language model responses, speech synthesis and telephony, and supports function calling so agents can look up and write data during a conversation.
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