Sierra
Enterprise AI company providing Agent OS and related tools for building, deploying and improving customer-facing AI agents across chat, voice and digital channels.
October 20261
Oct 7, 2026Sierra open roles snapshotOpen roles
A third-party company tracker listed 53 open roles at Sierra.
September 20261
Sep 28, 2026Ghostwriter expands to Slack and TeamsFeature update
Sierra expanded Ghostwriter into Slack and Microsoft Teams as an always-on, proactive and asynchronous teammate.
August 20261
Aug 7, 2026Sierra launches Voice PersonasProduct launch
Sierra launched Voice Personas so companies can design how an agent expresses a distinct brand personality.
July 20261
Jul 16, 2026Sierra launches Horizon AgentsProduct launch
Sierra launched long-horizon agents that orchestrate inbound and outbound interactions over days or weeks using persistent context and planning.
May 20262
May 4, 2026Sierra serves over 40% of the Fortune 50User count
Sierra reported serving more than 40% of the Fortune 50, with agents on its platform powering billions of customer interactions.
May 4, 2026Sierra raises $950MFunding round
Sierra raised $950 million from new and existing investors led by Tiger Global and GV.
March 20262
Mar 31, 2026Sierra headcount estimateEmployee count
Revelio Labs estimated Sierra's workforce at approximately 756 employees in the first quarter of 2026.
Mar 25, 2026Sierra introduces GhostwriterProduct launch
Sierra introduced an agent that creates, executes and continuously improves other customer-experience agents from described outcomes.
February 20261
Feb 6, 2026Sierra exceeds $150M ARRRevenue disclosure
Sierra reported more than $150 million in annual recurring revenue as it entered its third year.
November 20254
Nov 21, 2025Sierra reaches $100M ARRRevenue disclosure
Sierra announced that it reached $100 million in annual recurring revenue seven quarters after its public launch.
Nov 5, 2025Sierra launches Agent Data PlatformProduct launch
Sierra launched Agent Data Platform to provide agents with memory, context and intelligence across interactions.
Nov 5, 2025Sierra launches Agent OS 2.0Feature update
Sierra unveiled Agent OS 2.0, expanding agents from answering questions toward persistent memory, cross-channel action and customer relationships.
Nov 5, 2025Sierra launches Agent Studio 2.0Feature update
Sierra launched Agent Studio 2.0 with more powerful journeys, integrations and release-management capabilities available through a collaborative interface.
September 20253
Sep 18, 2025Sierra launches Agent StudioProduct launch
Sierra launched a no-code environment that enables customer experience teams to build and manage AI agents.
Sep 4, 2025Sierra reports hundreds of enterprise customersUser count
Sierra reported hundreds of customers across financial services, healthcare, telecommunications, retail and consumer services.
Sep 4, 2025Sierra raises $350MFunding round
Sierra raised $350 million in additional capital led by Greenoaks to expand Agent OS and its international business.
October 20241
Oct 6, 2024Sierra launches VoiceProduct launch
Sierra launched full-duplex voice capabilities for customer-facing AI agents.
February 20241
Feb 13, 2024Sierra launches Agent OSProduct launch
Sierra publicly launched its enterprise platform for building customer-facing AI agents.
* Market cap / valuation. Company values are AI-attributed: the latest market cap or valuation × the share attributed to AI (100% for pure AI companies). Methodology