Now you can build real-time voice agents that are truly dynamic and engaging using Inworld’s state-of-the-art voice AI on Vapi dashboard. Inworld’s TTS delivers studio quality and real-time latency, but at ~5% of the cost of alternatives. You can learn more about Inworld’s text-to-speech (TTS) models here.
Why Inworld + Vapi for voice AI
Emotionally expressive, contextually-aware voices vs. robotic chatbots are key for interactive experiences with voice agents. You can now access Inworld’s pre-built voices to build high-quality voice agents on Vapi’s platform. We made it seamless for developers to create assistants, coaches, characters, and more with dynamic personalities and understanding. Using Vapi, you can design suites of simulated voice agents and test different prompts, voices, and flows to optimize performance before going to production.
- Expressive voices: Choose from dozens of pre-built Inworld voices that have been trained on diverse datasets to capture subtle nuances in tone and prosody. Inworld voices make AI interactions feel more natural, which was previously only achievable via high-end custom pipelines.
- Multilingual: Build agents in 11 of the most common languages for consumer applications, including English (with its various accents), Chinese, Korean, Dutch, French, Spanish, and more.
- Accessible pricing: Studio-quality voices for just $5/M characters, which is 5% of the cost of TTS from leading labs, so you can build engaging experiences that scale with your users.
- Streaming-ready: Inworld voices support ~200ms latency to the first audio chunk to meet a range of voice agent use cases.
- API-native: Everything is exposed on Vapi as an API, with 1000s of configurations and integrations. Plug in your APIs as tools to intelligently fetch data and perform actions on your server.
By developers, for developers
Create a Vapi account to easily access the catalog of Inworld voices in a variety of languages. In your Vapi dashboard, you can test messaging and customize the system prompt to your brand, narrative tone, or interaction type. Just press ‘Talk to Assistant’ to start testing.

Interested in learning more? You can find additional details here.
Inworld x Vapi collaboration
Together, Inworld and Vapi want to simplify the complexities inherent in voice AI for developers. By abstracting intricate technical details, developers can focus on crafting the core logic of their voice agents and adapt instantly to users.
We’re thrilled to partner with Vapi to bring high-quality, real-time latency voices at a radically more accessible price point to their developer community. By democratizing access to state-of-the-art TTS technology, we’re excited to empower the next wave of innovation in voice-first experiences.”
Jean Wang, Inworld Head of Product.
Working with Inworld helps us open up new possibilities for developers building expressive, real-time voice agents. The focus is always on giving builders access to great tools, and this integration fits perfectly with that mission. We’re excited to see what our developer community creates next.”
Jordan Dearsley, Vapi Co-Founder