What is the best free alternative to Ultravox?
Bolna is the closest free alternative to Ultravox: same Real-Time Voice Agents sub-category, and it is free. Open-source framework for phone voice agents, from an India-based team
Best free Ultravox alternatives
Looking for a free alternative to Ultravox? Here are 9 real-time voice agents worth trying — 9 with a free tier. Ultravox itself is free tier + paid.
| Tool | Ultravox (you searched) | Bolna | Kyutai Unmute | Vapi |
|---|---|---|---|---|
| Pricing | freemium | free | free | freemium |
| Best for | Speech-native processing skips the STT-to-text bottleneck, preserving tone/cadence/pitch | Open-source framework for phone voice agents, from an India-based team | Wraps any text LLM with Kyutai's streaming speech-to-text and text-to-speech for voice conversation | Orchestrates STT/LLM/TTS providers of choice into one low-latency voice-agent pipeline |
| Visit | Open ↗ | Open ↗ | Open ↗ | Open ↗ |
Ultravox alternatives — straight answers
Are there free Ultravox alternatives?
Yes — 9 of the 9 alternatives listed here are free or freemium: Bolna, Kyutai Unmute, Vapi, Retell AI, Bland AI. None of them are paid-only.
Is Ultravox free?
Ultravox is free tier + paid. There is a free tier you can work in, with paid plans above it.
How were these Ultravox alternatives chosen?
They are the other tools in Real-Time Voice Agents, then the rest of AI Agents & Automation, ordered free tiers first and capped at 9. There is no sponsorship and no paid placement in that ordering — only the pricing tier decides.
All Ultravox alternatives
Browse Real-Time Voice Agents →✦ WhyA Ultravox alternative — Open-source framework for phone voice agents, from an India-based team.
- Open-source framework for phone voice agents, from an India-based team
- Connects to telephony, STT, LLM and TTS providers of your choice
- Supports Indian languages
- Self-host free; hosted platform is pay-as-you-go
✦ WhyA Ultravox alternative — Wraps any text LLM with Kyutai's streaming speech-to-text and text-to-speech for voice conversation.
- Wraps any text LLM with Kyutai's streaming speech-to-text and text-to-speech for voice conversation
- Open-source code and weights that can be self-hosted
- Low-latency interruptible conversation
- Free demo available online
Vapi
Real-Time Voice Agents
✦ WhyA Ultravox alternative — Orchestrates STT/LLM/TTS providers of choice into one low-latency voice-agent pipeline.
- Orchestrates STT/LLM/TTS providers of choice into one low-latency voice-agent pipeline
- Usage-based per-minute pricing with free trial minutes included
- SOC 2/HIPAA/PCI compliance add-ons for regulated call-center deployments
Retell AI
Real-Time Voice Agents
✦ WhyA Ultravox alternative — Free starting credit with no contract required.
- Free starting credit with no contract required
- Supports swapping GPT, Claude or Gemini as the reasoning layer per agent
- Batch calling campaigns plus live AI-to-human call transfer built in
Bland AI
Real-Time Voice Agents
✦ WhyA Ultravox alternative — All-in-one per-minute pricing bundles LLM+STT+TTS with no separate token pass-through charges.
- All-in-one per-minute pricing bundles LLM+STT+TTS with no separate token pass-through charges
- Free start with call credits plus an inbound number included
- Tiered platform fees (Build/Scale) unlock lower per-minute rates for high volume
LiveKit Agents
Real-Time Voice Agents
✦ WhyA Ultravox alternative — Apache-2.0 open-source framework, fully self-hostable on your own servers.
- Apache-2.0 open-source framework, fully self-hostable on your own servers
- Native WebRTC client support across web/mobile/telephony out of the box
- Native Model Context Protocol (MCP) support for tool-using voice agents
Pipecat
Real-Time Voice Agents
✦ WhyA Ultravox alternative — BSD-2-Clause open-source Python framework for real-time voice/multimodal agents.
- BSD-2-Clause open-source Python framework for real-time voice/multimodal agents
- Supports distributed multi-agent systems with handoffs over a shared bus
- Maintained by Daily with an active plugin ecosystem for STT/LLM/TTS providers
✦ WhyA Ultravox alternative — Open-source framework for real-time conversational voice and multimodal agents.
- Open-source framework for real-time conversational voice and multimodal agents
- Modular graph of extensions in Python, Go, C++ and Node
- Ships a playground and a VAD and turn-detection model
- Free to self-host under an open license
✦ WhyA Ultravox alternative — Open-source ESP32 voice chatbot with wake word, Opus streaming and a display.
- Open-source ESP32 voice chatbot with wake word, Opus streaming and a display
- Free official server lets personal users try a Qwen real-time model after registering
- Device-side and cloud MCP for controlling IoT gadgets
- MIT licensed firmware supporting many ESP32 chips