Vapi

Agent Frameworks active ★ 3.5 freemium · $0.05/min Free tier available

Vapi is a developer platform designed for building, testing, and deploying advanced AI voice agents. It offers a highly configurable API-first approach, enabling developers to create human-like conversational experiences with low latency. The platform supports both inbound and outbound calls, making it suitable for scaling phone operations and integrating with existing workflows.

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Key Features

API-Native PlatformEverything is exposed as an API, providing developers with extensive control and integration capabilities for building voice agents.

Bring Your Own ModelsAllows users to integrate their preferred transcription, LLM, and text-to-speech models, offering flexibility and leveraging existing investments.

Tool CallingEnables voice agents to intelligently fetch data and perform actions by plugging into external APIs and services.

Multilingual SupportSupports over 100 languages, allowing for global deployment of voice agents and catering to diverse user bases.

Real-time PerformanceOffers sub-500ms latency and enterprise-grade reliability for natural, human-like conversational experiences.

Automated Testing & A/B ExperimentsProvides tools for designing test suites and running A/B experiments to optimize agent performance and identify potential issues.

Use Cases

Building AI voice assistants for inbound customer service
Automating outbound sales or support calls
Integrating conversational AI into web and mobile applications

Pros

Highly configurable and API-native, offering extensive customization for developers
Supports bringing your own LLM, TTS, and STT models for flexibility and cost control
Features like tool calling, automated testing, and A/B experiments enhance agent capabilities and optimization
Designed for enterprise-grade reliability, scalability, and security with sub-500ms latency

Cons

Pricing can be complex due to usage-based model and separate charges for underlying AI models
Requires technical expertise for full utilization of its developer-centric features
Some user reviews indicate mixed experiences, suggesting potential areas for improvement in user support or ease of use

Pricing

Plan	Price
Free	Free
Pay As You Go	$0.05/minute
Enterprise	Free

Works With

ChatGPTCan be used as the underlying Large Language Model (LLM) provider for Vapi voice agents.n8nIntegrates with n8n (or Make) for workflow automation, allowing voice agents to trigger and interact MakeIntegrates with Make (formerly Integromat) for workflow automation, allowing voice agents to trigger

Comparisons

Vapi vs ElevenLabsVapi focuses on the full voice agent orchestration, while ElevenLabs specializes in high-quality voice synthesis (TTS). Vapi can integrate with ElevenLabs.Vapi vs LangChainLangchain is a framework for building LLM-powered applications, including agents. Vapi provides a more specialized platform for voice agents, handling real-time audio and telephony.