Sierra is an enterprise AI platform launched in February 2024 by Bret Taylor (former Salesforce co-CEO, current OpenAI board chair) and Clay Bavor (former Google exec who led Gmail, Google Drive, and Google Labs). The company is headquartered in San Francisco and reached a $15.8 billion valuation in its Series C round, having grown to $150 million ARR by early 2026 — a pace that made it one of the fastest enterprise software companies to hit those milestones.
Sierra's core product is an Agent Operating System (Agent OS): a full-stack platform for building, deploying, and operating customer-facing AI agents. Its technical differentiation is a constellation architecture that orchestrates 15 or more specialized LLMs from OpenAI, Anthropic, and Meta, routing each discrete task — retrieval, classification, tool-calling, generation — to the best-suited model rather than relying on a single foundation model. This approach provides both quality optimization and failover resilience.
The platform covers the full CX channel mix: chat, voice, SMS, WhatsApp, email, and ChatGPT. Recent additions include Ghostwriter (March 2026), a conversational agent builder, and Expert Answers (January 2026), which auto-generates grounded knowledge articles from resolved conversations. Sierra is exclusively enterprise-targeted with no self-serve tier and custom-negotiated contracts. Clients include more than 40% of the Fortune 50.
Key Benefits
- Multi-model orchestration: The constellation of 15+ LLMs automatically assigns each agent sub-task to the right model, improving output quality and providing automatic failover if any single provider has an outage.
- Outcome-aligned pricing: The resolution-based model means Sierra's incentives are aligned with customer deflection rates — you only pay when the AI actually resolves the issue.
- Continuous self-improvement: Expert Answers mines resolved conversations to build and update knowledge articles, so the agent gets better without manual curation.
- Full omnichannel reach: A single Agent OS deployment covers chat, voice, SMS, WhatsApp, email, and the ChatGPT connector from one platform, eliminating fragmented point solutions.
- Enterprise-grade reliability: Model failover, real-time monitoring via Experience Manager, and battle-tested deployments across Fortune 50 companies provide high operational confidence.
Use Cases
- High-volume B2C support automation — Retailers, telcos, and fintechs use Sierra to resolve order management, billing, and account queries autonomously at scale without increasing headcount.
- Voice-first contact center modernization — Enterprises replacing legacy IVR systems deploy Sierra's voice channel for inbound resolution and outbound follow-up with natural conversational quality.
- Omnichannel CX unification — Companies consolidating support across web chat, SMS, WhatsApp, and email under one agent platform, ensuring consistent brand voice and policy enforcement.
- Knowledge base automation — CX teams use Expert Answers to generate and maintain support documentation directly from agent-resolved conversations, reducing manual knowledge management overhead.
