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Summary
- ElevenLabs and Sierra.ai are conversational AI platforms offering tools to create advanced voice agents.
- ElevenLabs develops its own TTS and STT models, which offer advantages in latency and quality, while Sierra.ai focuses on brand-aligned AI agents for business process automation.
- Both platforms offer integration with external APIs, telephony systems, and knowledge base management.
- ElevenLabs supports 70+ languages, making it an excellent option for multilingual agents.
Overview
ElevenLabs and Sierra.ai are leading conversational AI orchestration platforms, each bringing unique strengths to the table. ElevenLabs provides in-house TTS and STT models, ensuring low latency and high voice quality, while Sierra.ai focuses on creating personalized AI agents that align with a brand’s tone and can execute business processes. Both platforms offer extensive integration capabilities, API support, and tools for knowledge base management.
Introduction to ElevenLabs and Sierra.ai
Conversational AI orchestration platforms, like ElevenLabs and Sierra.ai, enable developers to create customizable voice agents. These voice agents now handle customer support calls, train 911 dispatchers, and power new journalistic experiences.
Most platforms combine speech-to-text (STT), a large language model (LLM), and text-to-speech (TTS), along with built-in turn-taking and interruption handling, to support natural, human-like conversations. Many companies, like Sierra.ai, partner with other organizations to provide each of these components.
In contrast, ElevenLabs is both a research and product company that creates foundational audio models and offers a packaged solution. This integrated approach allows ElevenLabs to optimize latency by eliminating the need for multiple server calls, providing users with the highest quality TTS and STT in-house.
Feature comparison
To get a better understanding of each platform’s unique strengths, let’s explore them in more detail:
| Provider | ElevenLabs | Sierra.ai |
|---|---|---|
| Includes an extensive voice library | Includes an extensive voice library with over 5,000 voices across 70+ languages and numerous regional accents. Users can design new voices from a text prompt or clone their own. | Offers personalized AI agents that align with a company's brand tone and voice. |
| Latency | Uses the Flash model, which is the fastest, most human-like TTS available. Also has an advantage for end-to-end latency, saving two server calls through in-house TTS and STT. | Emphasizes real-time support and action-taking capabilities. Specific latency metrics are not publicly disclosed. |
| Tools & API Calls | Provides server tools to call third-party apps or APIs to fetch real-time information or take action. Also offers client tools to trigger browser events, run client-side functions, or send notifications to a UI. | Sierra.ai agents can update CRM entries or manage orders, integrating smoothly with existing business systems. |
| Languages | Supports 30+ languages. Allows users to set a custom voice or first message for each language. | Language support details are not publicly disclosed. |
| Concurrency | Concurrency by tier for ElevenLabs base plans is available here. Custom limits are available to handle scale for the largest enterprises. | Specific concurrency limits are not publicly disclosed. |
| LLM | Allows users to select from leading models from OpenAI, Anthropic, Google, and DeepSeek or integrate their own custom LLM. | Employs a constellation of large language models (LLMs) from providers like OpenAI, Anthropic, and Meta to ensure high reliability. |
| Knowledge Base Management | Allows users to import files, URLs, or plain text to equip their agents with relevant, domain-specific information. | Allows users to import files, URLs, or plain text, empowering AI agents with accurate, domain-specific knowledge. |
| Telephony Integrations | Offers PCM 8000 Hz or μ-law 8000 Hz sample rates for integration with any provider. For additional information, refer to the Twilio quickstart guide. | Integrates with existing call center ecosystems, providing comprehensive summaries and intelligent routing when escalation is required. |
| Data Retention | By default, ElevenLabs retains conversation data for 2 years. Users can modify this period to any number of days, unlimited retention, or immediate deletion. | Emphasizes data privacy. It states that customer data is only used for the company's agent and is not used to train models. Specific data retention periods are not publicly disclosed. |
| Tracking & Analytics | Allows users to review past recordings, transcripts, and call summaries. Offers custom prompts to tag calls based on internal success criteria and extract data from transcripts. | Offers analytics and reporting tools to continuously improve the customer experience. Built-in quality assurance workflows help understand the reasoning behind every AI interaction. |
Final thoughts
Based on the side-by-side comparison above, both ElevenLabs and Sierra.ai offer powerful AI-powered voice solutions.
ElevenLabs offers an extensive voice library, integrated STT and TTS services, and comprehensive language support, making it suitable for various use cases. Similarly, Sierra.ai enables developers to create personalized AI agents that align with a company's brand, focusing on enhancing customer engagement.
While both platforms provide solid features for conversational AI agent development, your final choice depends on your unique requirements.
FAQs
ElevenLabs offers an in-house TTS and STT solution that reduces latency and enhances voice quality. Sierra.ai specializes in brand-aligned AI agents capable of executing business tasks and integrating them into enterprise systems.
ElevenLabs allows for detailed voice customization, including creating new voices from text prompts or voice cloning. Sierra.ai offers personalized AI agents, but specific voice customization features are not publicly disclosed.
Yes, ElevenLabs and Sierra.ai support integration with telephony systems, including Twilio and existing call center ecosystems.
ElevenLabs allows importing files, URLs, and plain text to provide domain-specific information. Sierra.ai focuses on aligning AI agents with a company’s policies, processes, and knowledge base.
ElevenLabs offers customizable data retention policies, including immediate deletion and extended retention. Sierra.ai emphasizes data privacy, ensuring customer data is not used to train external models, but specific retention periods are not disclosed.
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