Inworld is acquiring Ultravox, the platform for building real-time voice agents. Existing customers get an immediate upgrade: built-in Inworld voices move to Realtime TTS-2.

According to Inworld, existing voice IDs keep working, with no migration, code changes or additional cost for the upgrade.

Developers can also direct how an agent speaks using natural-language instructions. A support agent could slow down while explaining a complicated step, then use a warmer tone when reassuring a customer.

The acquisition brings Ultravox’s speech understanding and handling of conversational turns and interruptions together with Inworld’s voice models. Members of the Ultravox team are joining Inworld and will continue developing the platform.

A useful combination for building agents that can follow a conversation and respond with the right delivery.