Sierra AI Overview & Best Alternatives in 2025

Sierra.ai: A Young Conversational AI Built on LLMs Only

Sierra.ai is a new  conversational AI company designed to help businesses build simple AI agents for customer interactions. Founded in 2023 by well-known personalities in the tech world, Sierra has quickly attained a high valuation, despite its limited track record, customer base and feature set which is well below established players like Cognigy, Kore.AI, Amelia and other Gartner Magic Quadrant™ leaders. Compared to other vendors, its current estimated value thus appears to be rather a reflection of investor interest in AI instead of in a unique product.  

Who Is Sierra.ai?

Sierra.ai was co-founded by Bret Taylor, former Salesforce co-CEO and current OpenAI board member and Clay Bavor, former Google executive who led Google Labs and key AR/VR initiatives. Their combined expertise in software and product design and likely VC connections set the foundation for Sierra’s successful funding. The company is headquartered in San Francisco, California with a team of over 30 people.

What Does Sierra.ai Do?

Sierra.ai enables companies to create and deploy personalized, action-oriented AI agents for customer service and business interactions. Unlike traditional chatbots, Sierra’s agents are designed to:

• Engage in natural, human-like conversations with customers

• Take self-service actions, such as updating CRM entries, managing orders or scheduling deliveries
  
  

• Integrate with enterprise systems (CRM, order management, etc.)

• Maintain compliance, data privacy, and security standards. 

Sierra’s platform leverages a “constellation” of large language models (LLMs) including those from OpenAI, Anthropic, and Meta. However, being built solely on top of other vendors' LLMs, it does not offer NLU or rule-based options in addition, which are often better suited for structured, repeatable processes in industries like finance and healthcare. After the initial LLM excitement, many companies have turned to composite AI, mixing both NLU and LLM AI models based on use case, sensitivity and process structure. 

Sierra AI's Core Features

Sierra.ai offers many of the basic features required for Conversational AI:

• Security & Compliance: The platform emphasizes privacy, access controls and certifications, though large companies will need to ensure they have the extensive certifications required for enterprise.

• Custom Branded Agents:  Contact centers can tailor the agents to reflect their own branding and tone.

• Outcome-Based Pricing: Sierra offers an “outcome-as-a-service” model. Companies pay based on successful resolutions, though the exact definition of success (vs. a closed interaction) can be difficult to define.

• Action-Oriented AI: Beyond answering questions, Sierra’s agents can execute simple workflows and take actions within business systems, reducing the need for manual intervention.

When Was Sierra.ai Founded and How Has It Grown?

Sierra.ai was only founded recently in early 2023, inspired by the founders’ vision to democratize access to advanced AI for businesses of all sizes despite an already crowded market with nearly identical solutions. The company launched publicly in February 2024 after securing early enterprise clients like WeightWatchers, Sonos, SiriusXM, and OluKai, who used Sierra’s technology to manage thousands of customer conversations monthly.

Within its first year, Sierra raised $285 million in funding, including a $175 million round led by Greenoaks Capital, and reached a valuation of $4.5 billion. Its annualized revenue crossed $20 million by late 2024 reflecting the ongoing popularity of the AI market and explosion of vendors offering similar solutions. 

How Does Sierra.ai Work?

Sierra’s platform consists of two main components:

• AgentOS: The core operating system for building, deploying, and managing AI agents. It enables integration with company systems, knowledge bases, and compliance frameworks.

• Experience Manager: A suite of tools for designing branded conversational experiences, setting goals and guardrails, and monitoring agent performance in real time.

Sierra’s agents are trained on company-specific data and policies, supervised by additional AI layers to ensure compliance and accuracy. The platform supports omnichannel deployment (chat, voice, etc.) and is designed for easy integration with existing enterprise infrastructure.

Who Uses Sierra.ai?

Sierra primarily targets contact centers in B2C consumer brands seeking to automate and elevate their customer service operations. Their customers include WeightWatchers, Sonos, SiriusXM, OluKai and others.

Sierra.ai at a Glance

Is Sierra AI's Good for Customer Service?

Sierra.AI is one of many recent "LLM wrapper" startups, adding a nice user interface on top of other vendors' LLM models, without their own NLU or  custom model according to their website. While they do have a functional product which delivers value to small and medium sized businesses, they do not appear to offer unique technology or innovation, nor a track record of success in enterprise contact centers. 

Sierra AI’s Best Alternative: Cognigy

While Sierra provides a capable platform, Cognigy stands apart as the most advanced AI Agent platform purpose-built for enterprise contact centers with a long and public track record of success. Cognigy delivers a scalable, multilingual AI workforce that empowers enterprises to transform customer service with intelligent, humanlike interactions, available 24/7 across voice and digital channels.

Key Features of Cognigy

Cognigy offers a comprehensive enterprise-grade platform to automate customer interactions with AI Agents that understand, reason, act, and respond just like human agents. Cognigy integrates seamlessly into your existing contact center stack whether on-premises, cloud-based or hybrid and accelerates time-to-value, and delivers results at scale.

Enterprise-Ready AI Agents
Pre-trained and purpose-built for contact centers, Cognigy’s AI Agents offer hyper-personalized service, speak 100+ languages, and integrate with 100+ backend systems and 30+ channels.

Agentic AI for Dynamic Decision-Making
Unlike rule-based bots, Cognigy’s Agentic AI enables AI Agents to make real-time decisions, adapt to conversation context, and autonomously resolve issues using all available tools and data.

Collaborative by Design
AI Agents work seamlessly with human agents—qualifying and routing conversations, assisting in real time, and handing off with full context for fast, efficient resolution.

Low-Code Flexibility
Business users, designers, and developers can quickly build and deploy AI solutions using a visual, low-code interface with powerful orchestration and plug-and-play integrations.

Fast Time-to-Value
Cognigy comes with prebuilt AI Agents and turnkey contact center integrations, enabling enterprises to go live in weeks, not months.

Enterprise-Grade Compliance & Security
SOC2, ISO, GDPR and HIPAA compliant, Cognigy ensures secure, compliant deployments across SaaS, private cloud, or on-prem environments.

Join leading global brands like Frontier Airlines, Bosch, Lidl, DHL Lufthansa, and Toyota in redefining customer service with Cognigy.