Explore five alternatives to ElevenLabs for AI phone agents, comparing costs, concurrency, and telephony compatibility.
As companies seek alternatives to ElevenLabs for AI-powered phone agents, understanding the technical and operational changes involved is critical. This guide evaluates five text-to-speech (TTS) providers—AssemblyAI, Inworld, Cartesia, Deepgram, and Rime—focusing on their pricing, concurrency models, and telephony compatibility.
Several factors have prompted organizations to explore replacements for ElevenLabs. The platform's session-based concurrency limits, idle connection timeouts, and its removal from LiveKit Inference on August 31, 2026, are notable constraints. For example, ElevenLabs' Text to Dialogue WebSocket connections are metered as dialogue sessions, with limits based on plan tiers. Open connections past the limit are rejected, and idle connections close after 20 seconds unless kept alive. These restrictions can hinder scalability for phone agents handling high call volumes or long pauses.
AssemblyAI-TTS-1 offers a concurrency model based on call starts rather than open calls, which can simplify scaling. It supports native pcm_mulaw and pcm_alaw at 8 kHz and provides US and EU data zones. Pricing is $15 per 1 million characters with no commitment. However, it supports only six languages (English, Spanish, French, German, Italian, and Portuguese) and lacks advanced controls like speed, pitch, and emotion parameters. In benchmark tests, AssemblyAI-TTS-1 achieved 93.7% entity accuracy, comparable to ElevenLabs v4 at 93.6%.
Inworld's TTS-2 and TTS-2 Flash models cover over 200 languages and locales. Concurrency is measured in generations, with limits ranging from 5 on the On-Demand plan to 500 on the Growth plan. WebSocket connections are capped separately at 10 times the generation limit.
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