Blogs/AI/Difference Between VAPI AI vs RETELL AI Voice AI Platforms
Difference Between VAPI AI vs RETELL AI Voice AI Platforms
Mar 18, 2025 • 4 Min Read
Written by Kiruthika
Selecting the optimal AI voice platform has become a critical strategic decision for organizations aiming to enhance customer engagement and operational efficiency in an increasingly competitive market. Two prominent contenders in this space are Vapi AI and Retell AI, each offering unique features tailored to diverse business needs. This comprehensive analysis delves into the strengths and weaknesses of both platforms, providing a detailed comparison to assist in making an informed decision.
What is Vapi AI
Vapi AI is a developer-centric platform designed to empower businesses with customizable tools for building advanced voice AI agents. It caters to enterprises seeking deep customization and flexibility in their voice applications.
PROS
CONS
Enhanced User Experience
Complex Pricing Structure
Advanced Language Processing
Limited Free Concurrency
Strong Developer Support
Restricted Telephony Integration
Robust Customization Options
Lower Uptime Guarantee
What is Retell AI
Retell AI is a platform designed to enhance phone call interactions through advanced AI capabilities, providing features like live transcription and tool calling. It ensures compliance with industry standards by being HIPAA compliant, with SOC 2 Type II compliance in progress.
PROS
CONS
User-Friendly Interface
Limited Customization for Developers
High reliability
Potential Latency Issues
Flexible Pricing Model
Limited Voice Cloning Capabilities
Comprehensive Feature Set
Limited number of agents that can be deployed
Feature Comparison between Vapi AI and Retell AI
Now, we’ll explore the key differences between the basic features of Vapi AI and Retell AI, comparing their capabilities, performance, and suitability for various use cases.
Feature
Vapi AI
Retell AI
Notes
Agent Builder
Single Prompt & Agent Blocks
Single Prompt & Multi Prompt
Retell's multi-prompt system offers more flexibility in conversation design
Custom LLM Support
Yes - Multiple model support
Yes - Multiple model support
Both platforms allow integration with various LLM providers
Multilingual Support
35+ languages
19 languages
Vapi offers broader language coverage
Voice Quality
High-quality TTS
High-quality TTS
Retell offers additional audio customization
Latency
Sub-second latency
Sub-second latency
Both platforms offer similar performance
Uptime SLA
99.94%
99.99%
Retell offers slightly better reliability
Concurrent Calls
10 free concurrent calls
20 free concurrent calls
Retell provides better free tier capacity
Response Time
Real-time
Real-time
Both platforms offer quick response times
Custom Telephony
Limited to Twilio and Vonage
Supports SIP trunking to any telephony
Retell offers more flexible telephony options
Webhook Support
Yes
Yes
Both support real-time event notifications
Post-call Analysis
Yes
Yes
Both offer call analysis capabilities
Real-time Monitoring
Yes
Yes
Both provide live monitoring features
Call Recording
Available with transcription
Available with transcription
Both support call recording
Compliance Certifications
HIPAA, GDPR & SOC 2
(HIPAA: $1,000/month additional)
HIPAA, GDPR, SOC 2 Type 1 & Type 2
(All included)
Retell offers more comprehensive compliance coverage
Webcall Support
Yes
Yes
Both support web-based calling
Knowledge Base
Supported
Supported
Both offer knowledge base integration
Why Choose One Over the Other?
When deciding between Vapi AI and Retell AI, consider the following factors:
Customization Needs: If your business requires deep customization and has the technical expertise to manage complex configurations, Vapi AI's robust customization options and strong developer support may be advantageous.
User-Friendly Experience: For businesses seeking an intuitive interface with comprehensive features and high reliability, Retell AI offers a user-friendly platform with a wide range of functionalities and a higher uptime guarantee.
When choosing between Vapi AI and Retell AI, it's essential to align the platform's strengths with your business requirements:
Vapi AI is ideal for organizations seeking deep customization and possessing the technical expertise to manage complex configurations. Its robust developer support and extensive language processing capabilities make it suitable for enterprises with specific AI needs.
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However, businesses should be mindful of its complex pricing structure and additional costs for compliance and support.
Retell AI offers a user-friendly interface with a comprehensive feature set, including live transcription, customizable call parameters, and tool calling. Its flexible pricing model and higher uptime guarantee make it a reliable choice for businesses aiming for quick deployment and high reliability.
While it may have limited deep customization options, it provides sufficient flexibility for most business applications.
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What Customers Think About Vapi AI and Retell AI
Customer feedback provides valuable insights into the real-world performance of these platforms:
Vapi AI
"Amazing System that they are building. I had issues on a Saturday night, and received a phone call from one of the technicians Sahil and he helped me through my issue. What dedication. I saw some of the other reviews, and they seem to be related to billings, and stuff that could easily be spoken about. I just wanted to give a shout-out to this guy for his passion and dedication to the project." - Robert Peter
Retell AI
Users appreciate Retell AI's efficiency and natural interactions. One reviewer stated, "We’ve been using Retell to build these voice agents for our customer service, for over a year. It’s so natural, people don’t even realize it’s not a human half the time."
Another user highlighted the platform's cost-effectiveness, noting, "Retell AI has no platform fees, meaning you only pay for what matters: the API cost."
In conclusion, both Vapi AI and Retell AI offer valuable features for enhancing voice interactions. Your choice should depend on your organization's specific needs, technical capabilities, and budget considerations. For businesses requiring deep customization and possessing technical expertise, Vapi AI may be the preferred choice.
Conversely, for those seeking a user-friendly platform with comprehensive features and flexible pricing, Retell AI stands out as a compelling option.
Kiruthika
I'm an AI/ML engineer passionate about developing cutting-edge solutions. I specialize in machine learning techniques to solve complex problems and drive innovation through data-driven insights.
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