Sierra
Sierra is a conversational AI platform for customer experience, founded in 2023 by Bret Taylor (former co-CEO of Salesforce, CTO of Facebook, co-creator of Google Maps, and current chair of OpenAI's board) and Clay Bavor (former Google VP who led Labs, Project Starline, Google Lens, and Google Workspace). Headquartered in New York with offices in San Francisco, Atlanta, London, Paris, Madrid, Toronto, Singapore, and Tokyo, Sierra builds branded AI agents that handle customer service, sales, and operational interactions across chat, voice, SMS, WhatsApp, email, and ChatGPT for enterprises including SiriusXM, WeightWatchers, Sonos, ADT, Chime, Sutter Health, Rocket Mortgage, Ramp, Brex, SoFi, Casper, CLEAR, Vivid Seats, Wayfair, AOL, and approximately 40% of the Fortune 50. The platform is anchored by Agent OS 2.0, with Agent Studio (no-code builder for CX teams), Agent SDK (a developer-facing programmatic layer that lets engineering teams write customer journeys as code), Agent Data Platform (persistent cross-session memory unifying structured CRM data and unstructured conversation history), Insights (analytics — Explorer, Monitors, Experiments, Observability), Live Assist (human-in-the-loop), Voice (real-time voice agents), and Ghostwriter (an agent-building agent that generates production-ready multilingual agents from SOPs, transcripts, audio recordings, whiteboard photos, or plain English in 30+ languages). Sierra runs an outcome-based pricing model — customers pay per resolved case, not per seat or per token — and operates a gated developer documentation portal at docs.sierra.ai available only to contracted customers. There is no public REST API, no public Agent SDK package, no public GitHub org, and no self-serve sign-up; access is via enterprise sales. Sierra raised $950M at a $15.8B valuation in May 2026 (after a $350M round at $10B earlier in the year) and reported $150M ARR within roughly two years of public launch. Sierra also acquired the French agent-evaluation startup Fragment in April 2026 and publishes the public τ-bench, τ-voice, and τ-knowledge benchmarks for evaluating agentic systems.
More than an index entry, but the surface is still mostly links rather than artifacts — the cohort most likely to move a full band from modest, well-targeted work.
API Evangelist profiles Sierra the way a machine reads it — 36 machine-readable artifacts, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Sierra scores 15.9/100 (emerging), with a separate agent-readiness read of 0/100 (human only). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile Sierra
Each block below is one kind of artifact we hold for Sierra. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
Features 10
The notable capabilities this provider advertises, captured as structured features so they can be searched and compared instead of read one landing page at a time.
Notable capabilities this provider offers.
Agent OS 2.0
Multi-channel agent operating system spanning chat, voice, email, SMS, WhatsApp, ChatGPT, and contact-center integrations with shared memory, learning, and live human assist.
Agent Studio
No-code builder for CX teams to design agents using natural-language instructions and a collaborative workspace with simulations and guardrails.
Agent SDK
Developer-facing programmatic layer that lets engineering teams write customer journeys as code, version them in their existing source control, and orchestrate composable skills...
Agent Data Platform
Persistent agent memory unifying structured customer data (CRM, billing) with unstructured conversation history to enable personalized, relationship-aware responses across sessi...
Insights
Analytics suite — Explorer (deep-research style conversation analysis), Monitors, Experiments, and Observability — for measuring and improving agent performance.
Live Assist
Human-in-the-loop interface that surfaces real-time answers and captures conversation details to augment human agents.
Voice
Real-time voice agents benchmarked publicly via Sierra's τ-voice benchmark; deployable into contact centers and IVR replacements.
Ghostwriter
Agent-building agent that ingests SOPs, support transcripts, whiteboard photos, audio recordings, and plain-English descriptions to generate production-ready agents across voice...
Trust and Reliability
Built-in guardrails, evaluations, simulations, and observability targeted at regulated industries (financial services, healthcare, telecom).
Outcome-Based Pricing
Customers pay per resolved case (outcome) rather than per seat or per token, aligning Sierra's revenue with measurable customer outcomes.
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Security Posture 3
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Use Cases 9
What developers actually build with this provider — captured so the catalogue answers 'what is this for', not just 'what does this expose'.
What developers build with this provider.
Customer Service Automation
Branded AI agents handle Tier-1 support across chat, voice, SMS, and email — Chime, Ramp, Wilson, and Pendulum report case resolution rates of 70–90%.
Voice / IVR Replacement
Real-time voice agents replace traditional IVR menus for providers such as R1 RCM, Singtel, and ADT, which handles ~2M monthly inquiries.
Sales and Conversion
Conversational agents drive product discovery and conversion (Rocket Mortgage 4× conversion, Sun & Ski 3× conversion, Redfin 2× listing views).
Healthcare Member Support
HIPAA-compliant agents for chronic care management, member enrollment, and patient navigation (Sutter Health, Cigna, WeightWatchers).
Financial Services
Agents for fintech onboarding, account servicing, and dispute resolution (SoFi +33 NPS, Chime 70%+ resolution, Brex 90% faster).
Retail and E-Commerce
Order tracking, returns, sizing, and personalization across brands like Casper, Minted, ThirdLove, BARK, Chubbies, and Sonos.
Subscription and Media
Subscriber retention and support for SiriusXM (34M subscribers), AOL, Tubi, and WeightWatchers.
Telecom
Plan changes, troubleshooting, and billing for Singtel and Next.
Multi-Brand Agent Hosting
Single agent runtime serving multiple brands under one customer (e.g., Imprint).
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Integrations 7
Pre-built integrations with other platforms tell you where this provider already fits in a stack.
Pre-built integrations with other platforms and tools.
ChatGPT
One-click publish of a Sierra agent into the ChatGPT app directory, extending brand reach inside OpenAI's consumer surface.
Native deployment of Sierra agents on the WhatsApp Business channel.
SMS
Outbound and inbound SMS agent channels.
Email-as-a-channel for ticket-grade asynchronous interactions.
Contact Center Platforms
Integrations into existing CCaaS deployments for live-assist and voice handoff.
CRM and Billing Systems
Agent Data Platform ingests structured customer records from existing CRMs and billing engines.
Custom Backends
Agent SDK lets teams call any internal or external system from within an agent workflow.
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Solutions 7
Packaged solutions the provider offers on top of the raw API surface.
Packaged solutions this provider offers.
Financial Services
Vertical solution for banks, fintechs, and lenders with compliance tooling and case templates.
Healthcare
HIPAA-aligned deployments for payers, providers, and digital health.
Telecommunications
Carrier-grade agents for plan changes, troubleshooting, and retention.
Media and Subscriptions
Subscription lifecycle and content support.
Travel and Hospitality
Booking, itinerary changes, and concierge experiences (Woodside Collection).
Retail
Pre-purchase, post-purchase, and loyalty agents.
Technology
Developer tools and SaaS support workflows.
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Resources
Every other property we hold for Sierra — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 1
Portal, sign-up, and the first successful call
Documentation 1
Reference material describing how the API behaves
Access & Security 5
Authentication, authorization, and security posture
Operate 1
Status, limits, changes, and where to get help
Commercial 1
Pricing, plans, and the legal terms of use
Company 4
The organization behind the API
Other 4
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/sierra-ai · machine-readable index on apis.io