Best 6 Retell AI Alternatives in 2026

VoxImplant is a comprehensive cloud communications platform that enables businesses and developers to integrate voice, video, and messaging capabilities into their applications and services. Founded in 2013 and based in Palo Alto, the company serves millions of users worldwide through its innovative Communication Platform as a Service (CPaaS) solution.

The platform consists of two main products: VoxImplant Platform, which provides APIs and SDKs for custom development, and VoxImplant Kit, an omnichannel contact center solution. VoxImplant Platform supports multiple programming languages and frameworks including iOS, Android, React Native, Flutter, Unity, and web applications. The service includes advanced features like AI-powered voice bots, natural language processing, call recording, transcription, and seamless integration with popular AI providers like OpenAI, Google Gemini, and Dialogflow, making it perfect for creating sophisticated communication experiences.

VideoSDK is a real-time communication platform that provides APIs and software tools for developers to build video and voice applications. Instead of creating video calling systems from scratch, developers can use VideoSDK's ready-made tools to add features like video meetings, live streaming, screen sharing, and AI-powered voice agents to their apps.

The platform works across all devices and operating systems, including web browsers, mobile apps, and desktop applications. It uses advanced technology to ensure smooth video quality even with poor internet connections and provides global infrastructure with 150ms worldwide latency.

VideoSDK offers both free and paid plans, starting with 10,000 free minutes every month. This makes it perfect for startups, small businesses, and large companies that need reliable video communication features without building everything from scratch.

LiveKit is a complete real-time communication platform that uses WebRTC technology to enable low-latency audio, video, and data exchange between users and AI agents. Unlike traditional communication tools, LiveKit is built specifically for developers who want to create custom real-time experiences.

The platform consists of several parts: the open-source LiveKit server that handles media routing, client SDKs for all major platforms, and LiveKit Cloud for managed hosting. It uses a Selective Forwarding Unit (SFU) architecture, which means it can efficiently handle many participants without heavy server processing.

LiveKit is especially strong for AI applications. It can connect voice agents to phone systems, enable real-time transcription, and support multimodal AI that can see and hear simultaneously. Whether you want to build a simple video chat or a complex AI assistant, LiveKit provides the foundation you need.

Thunai is an enterprise AI platform that converts your organization's scattered knowledge into intelligent AI agents. Think of it as creating a digital brain for your company that understands all your documents, processes, and customer interactions.

The platform processes various content types including documents, videos, audio files, meeting transcripts, and chat conversations to build a comprehensive knowledge base. From this foundation, Thunai creates specialized AI agents that can handle voice calls, live chats, email responses, and complex customer support tasks. These agents don't just provide information they take actions, create tickets, schedule meetings, and execute workflows.

Founded by serial entrepreneurs with deep AI expertise, Thunai serves over 500 teams worldwide, helping them automate tier-1 support, assist tier-2 agents, and create seamless customer experiences across all touchpoints.

Vapi is a developer-focused platform that provides the infrastructure needed to build voice AI agents for phone interactions. Instead of spending months building voice technology from scratch, developers can use Vapi's APIs to create voice agents in minutes.

The platform works by combining several AI technologies: speech recognition to understand what people say, language models to generate smart responses, and text-to-speech to reply with natural voices. What makes Vapi special is its speed - conversations happen in real-time with responses under 500 milliseconds, making interactions feel natural.

Developers can choose from multiple AI providers like OpenAI, Google, and ElevenLabs, or bring their own models. The platform supports over 100 languages and includes security features that meet healthcare and financial industry standards. It's designed to scale from small projects to millions of calls.

Synthflow AI is a no-code voice automation platform that creates AI-powered phone agents for businesses. Instead of hiring more customer service staff, you can build virtual assistants that handle incoming and outgoing calls just like human employees would.

These voice agents understand what callers are saying and respond naturally in real-time. They can answer questions, schedule meetings, qualify sales leads, transfer calls to humans when needed, and even send follow-up messages. The platform includes ready-made templates for different industries like healthcare, real estate, and restaurants.

What makes Synthflow special is how realistic the conversations sound. Customers often don't realize they're talking to AI. The system works with your existing phone systems, calendars, and customer management tools, making it easy to add to your current business setup.