Vapi vs OpenAI Realtime API

Comparing the features of Vapi to OpenAI Realtime API

Feature
Vapi
OpenAI Realtime API

Capability Features

A/B Experiments
AI Guardrails
API Access
API Configurability
4.2K+ configuration points
API-First Architecture
Automated Test Execution
Automatic Scalability
Millions of calls
Bring Your Own Models
Community Support
13000
Custom Phone Number
Dedicated Deployment Engineer
Documentation
Enterprise Compliance
SOC2HIPAAPCI
Enterprise Privacy Commitment
Expanded Model Support Planned
Five New Voices
5
Function Calling
Human and Automated Safety Monitoring
Inbound Calls
Interruption Handling
Multi-language Support
100+ languages
No Training on Data Without Permission
No-code/Low-code Workflow
Outbound Calls
Playground Access
Prebuilt Templates
1000s
Prompt Caching Planned
Public Beta
Reference Client Available
Six Preset Voices
6
Speech-to-Speech
Streaming Audio Inputs/Outputs
Supports Text and Audio Inputs
TextAudio
Tool Calling
Ultra-low Latency
Sub-500ms
Uptime SLA
99.99% uptime
WebSocket Connection

Integration Features

Agora Integration
Chat Completions API Integration
Client SDK
React (web SDK)
Downloadable SDK ZIP
Github Repository
Integrations Information
40+ apps
LiveKit Integration
OpenAI Integration
openaigpt-4o
OpenAI Node.js SDK Planned
OpenAI Python SDK Planned
Server SDKs
TypeScriptPythoncURL
Supports GPT-4o
gpt-4o-realtime-preview
Twilio Voice API Integration

Limitation Features

AI Disclosure Requirement
Audio Only Modality (Initially)
Lower Session Limits Tiers 1-4
Lower than 100
No Built-in Telephony Provider Mentioned
No Explicit Pricing Details
No Explicit Usage Quotas Listed
No File Format Support Listed
No Simultaneous Session Limit Anymore
Simultaneous Sessions Limit Tier 5
100
Usage Policy Restriction

Pricing Features

Approximate Audio Input Price
$0.06/minute
Approximate Audio Output Price
$0.24/minute
Free Tier
No Free Tier
Pricing Audio Input
$100/1M tokens
Pricing Audio Output
$200/1M tokens
Pricing Cached Audio Input
$20/1M tokens
Pricing Cached Text Input
$2.50/1M tokens
Pricing Text Input
$5/1M tokens
Pricing Text Output
$20/1M tokens