Sierra AI
Teams evaluating an AI customer service platform ask the same three questions: can we self-host, can our team own it, and what does it actually cost? Here's how Rasa compares on the dimensions that decide enterprise deals
Two platforms, two opposite philosophies
Sierra AI is a managed conversational AI platform co-founded by Bret Taylor and Clay Bavor, positioned as an Agent OS for enterprise customer service. Sierra has raised over $1.4 billion (most recently a $950M round at a $15.8B valuation, as of May 2026) and serves brands like Sonos and WeightWatchers. It operates as a managed, cloud-based service with outcome-based, usage-based pricing; Sierra does not publish list pricing. Customization, integrations, and workflow changes are delivered with Sierra's team rather than via self-service configuration.
Rasa is an enterprise conversational AI platform built on a self-hosted, developer-owned architecture. Patented dialogue management (CALM) delivers guided governance: business logic controls high-risk actions through explicit policies, regardless of LLM output. Native voice (Twilio, AudioCodes, Genesys), 100% on-prem or private cloud, transparent conversation-volume pricing. Customers include N26, Deutsche Telekom, Helvetia, Autodesk.
One platform for voice and chat, running in your environment
Rasa runs the same guided-governance engine across phone and chat, fully self-hosted. Your team configures flows, policies, and integrations directly, with no managed-service dependency.
- Native voice over Twilio, AudioCodes, and Genesys, sharing context with chat.
- Explicit policies control high-risk actions on regulated workflows, regardless of LLM output.
- Deploy on-prem, in private cloud, or air-gapped, with no customer data leaving your perimeter.
Side-by-side on the six dimensions that decide enterprise deals
Five dimensions, side by side
Ownership vs. Managed Service Dependency
Sierra operates like a consulting engagement. Changing workflows or updating scripts is delivered with Sierra's team. As a managed service, prompts, policies, and the underlying codebase are not positioned as customer-accessible.
Rasa gives your team full control. Modify logic, update flows, and deploy changes without vendor dependency. Full access to prompts, policies, and codebase. Your engineering team is the system of record, not the vendor.
Self-Hosted Deployment for Regulated Industries
Sierra is delivered as a managed cloud service. As of May 2026, its public materials do not describe a self-hosted, on-prem, or air-gapped option, so customer data, conversation logs, and agent state are handled in Sierra's environment.
Rasa deploys self-hosted from day one. Rasa does not host any customer data, systems, or applications. Banking, healthcare, and government customers run Rasa entirely inside their own environment.
Data Sovereignty and Auditability
Cloud-only deployment means customer conversation data sits in Sierra's infrastructure. Audit trails are limited to what the managed service exposes.
Self-hosted from day one. Full audit trails on every decision the agent makes. N26 (banking) and Deutsche Telekom (10,000+ employee IT service desk) run Rasa in regulated environments.
Developer Platform vs. Managed Service
Sierra is a managed service. Integration changes, workflow updates, and customization are delivered with Sierra's team rather than self-service configuration.
Rasa is a developer platform with code-level extensibility. The Action Server and MCP integration model give engineering teams direct control over flows, integrations, and deployment.
Pricing Transparency
Sierra emphasizes outcome-based, usage-based pricing and does not publish list pricing. As with any outcome-based model, total cost depends on how a 'successful resolution' is defined and measured.
Rasa offers conversation-volume licensing with cost certainty at scale. Developer Edition is free for up to 1,000 conversations/month. Enterprise pricing is published and predictable.
Independently recognized for enterprise conversational AI
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