S

Sierra

Application

AI agents for customer service and enterprise interactions.

Total funding$1.6B

Valuation$15.8B

Employees549

Founded2023

HeadquartersSan Francisco, USA

StatusPrivate

Products

Selected offerings — the AI products recorded here, not the vendor's full catalogue.

• Sierra AI agent

  Platform for building and running customer-facing agents that handle support conversations over chat and voice.

Inside Sierra

• Agent Studio Application Included with the parent

  Empower customer experience teams to build and manage agents—without writing a line of code. Set up customer journeys, configure knowledge, and define brand guidelines effortlessly.

• Explorer Application Included with the parent

  Ask any question in natural language, and Explorer will use analytics and sample customer conversations to provide answers and actionable recommendations.

• Ghostwriter Application Included with the parent

  Build or modify your agent simply by describing how you want your agent to behave. Prompt workflows, systems integrations, guardrails, tone, and style.

• Horizon Application Included with the parent

  Long-horizon agents that get more intelligent with every interaction.

• Channels Application Included with the parent

  Create consistent experiences across voice, chat, email, and more in 58 languages, available 24/7/365.

• Insights Application Included with the parent

  Measure what matters, test what works, and understand every agent decision with analytics, experimentation, and observability built for continuous improvement.

• Context Engine Developer tool

  Supplies persistent customer context and behavioral signals to Sierra's conversational agents.

Closest alternatives 7

NNiCEPublic · $6.5B6 of 7 capabilitiesShared product typeSmaller scaleNamed in filingBuild and run AI agentsCompareCCrestaPrivate · $1.6BSame customer-support-agent job, same buyer.6 of 7 capabilitiesShared product typeSmaller scaleSourced competitorHandle customer support conversationsCompareDDecagonPrivate · $4.5BDecagon's own vs page.5 of 7 capabilitiesShared product typeSmaller scaleSourced competitorHandle customer support conversationsCompareFForethoughtPrivate · $115M raisedForethought's own comparison page.5 of 7 capabilitiesShared product typeSourced competitorHandle customer support conversationsCompareFFinAcquired ($3.6B deal)Fin AI's own vs page.5 of 7 capabilitiesShared product typeSourced competitorHandle customer support conversationsCompareSSalesforcePublic · $196.1BSalesforce's official /compare/ page names Sierra as a narrow point solution for building AI agents versus Agentforce's broader platform. Agentforce and Sierra's flagship product both carry build-ai-agents.4 of 7 capabilitiesShared product typeLarger scaleSourced competitorBuild and run AI agentsCompareKKore.aiPrivate2 of 7 capabilitiesDifferent layerSourced competitorHandle customer support conversationsCompare

Similar products 81

How this list is ranked ↗

CCognigyAcquiredChannels and Cognigy Voice Gateway do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; Cognigy is acquired, with no independent scale.6 of 7 capabilitiesShared product typeCompareLLivePersonAcquiredOverlaps on customer support, data analysis, evaluation and observability and 1 more; LivePerson is acquired, with no independent scale.4 of 7 capabilitiesShared product typeCompareYYellow.aiPrivateChannels and Agent Assist do comparable work on customer support; both also serve buyers who need to handle customer support conversations; Yellow.ai's scale not recorded.5 of 7 capabilitiesShared product typeCompareSServiceNowPublic · $130.1BOverlaps on agent orchestration, customer support, data analysis and 4 more; larger scale (public).7 of 7 capabilitiesShared product typeLarger scaleCompareHHaptikAcquired ($112M deal)Overlaps on agent orchestration, customer support, evaluation and observability and 1 more; Haptik is acquired, with no independent scale.4 of 7 capabilitiesShared product typeCompareGGenesysPrivateChannels and Predictive Engagement do comparable work on customer support; both also serve buyers who need to handle customer support conversations; smaller scale (private).6 of 7 capabilitiesShared product typeCompareSASoundHound AIPublic · $3.1BSierra and OASYS do comparable work on customer support and voice agent; both also serve buyers who need to create synthetic voice and audio and handle customer support conversations; smaller scale (public).3 of 7 capabilitiesShared product typeSmaller scaleCompareCCrescendoPrivate · $500MChannels and Crescendo Concierge do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; smaller scale (private).2 of 7 capabilitiesShared product typeSmaller scaleCompareFFive9Public · $2.7BChannels and Five9 Genius AI do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; smaller scale (public); ships platform rather than the same layer.2 of 7 capabilitiesDifferent layerSmaller scaleComparePParloaPrivate · $3BChannels and Parloa AMP do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; smaller scale (private).2 of 7 capabilitiesShared product typeSmaller scaleComparePPegasystemsPublic · $6.1BChannels and Pega Customer Service do comparable work on customer support; both also serve buyers who need to handle customer support conversations; smaller scale (public).4 of 7 capabilitiesShared product typeSmaller scaleCompareZZendeskPrivate · $10.2BSierra and AI Agents do comparable work on customer support; both also serve buyers who need to handle customer support conversations; same layer and the same scale band (late-stage private).7 of 7 capabilitiesShared product typeSame scale bandCompareTTwilioPublic · $36.5BChannels and Twilio Agent Copilot do comparable work on customer support; both also serve buyers who need to handle customer support conversations; larger scale (public).5 of 7 capabilitiesShared product typeLarger scaleCompareOOraclePublic · $454.4BOverlaps on agent orchestration, customer support, data analysis and 2 more; larger scale (public).5 of 7 capabilitiesShared product typeLarger scaleCompareZZoomPublic · $28.7BSierra and Zoom Virtual Agent do comparable work on customer support and voice agent; both also serve buyers who need to create synthetic voice and audio and handle customer support conversations; similar scale (public).7 of 7 capabilitiesShared product typeCompareWWorkdayPublic · $49.3BChannels and Workday Paradox Conversational ATS do comparable work on customer support; both also serve buyers who need to handle customer support conversations; larger scale (public).5 of 7 capabilitiesShared product typeLarger scaleCompareAAtlassianPublic · $48.2BChannels and Customer Service Management do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; larger scale (public).5 of 7 capabilitiesShared product typeLarger scaleCompareVSVeeva SystemsPublic · $45.5BChannels and Veeva Ostro do comparable work on customer support; both also serve buyers who need to handle customer support conversations; larger scale (public).3 of 7 capabilitiesShared product typeLarger scaleCompareEEliseAIPrivate · $384M raisedChannels and VoiceAI do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; similar scale (private).3 of 7 capabilitiesShared product typeCompareXXiao-iPublicSierra and Xiao-i cognitive intelligence platform do comparable work on customer support and voice agent; both also serve buyers who need to create synthetic voice and audio and handle customer support conversations; smaller scale (public).4 of 7 capabilitiesShared product typeCompareCCerencePublic · $384.9MSierra and Dealer Assist Agent do comparable work on voice agent; smaller scale (public).3 of 7 capabilitiesShared product typeSmaller scaleCompareKKrispPrivateChannels and Krisp Agent Assist do comparable work on customer support; both also serve buyers who need to handle customer support conversations; Krisp's scale not recorded.2 of 7 capabilitiesShared product typeCompareCCiscoPublic · $433.3BSierra and Webex AI Agent do comparable work on customer support and voice agent; both also serve buyers who need to create synthetic voice and audio and handle customer support conversations; larger scale (public).6 of 7 capabilitiesShared product typeLarger scaleCompareAAmazonPublic · $2.8TChannels and Amazon Connect Customer do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; larger scale (public).6 of 7 capabilitiesShared product typeLarger scaleCompareMmonday.comPublic · $3.9BOverlaps on agent orchestration, customer support and workflow automation; smaller scale (public).3 of 7 capabilitiesShared product typeSmaller scaleCompareHAHippocratic AIPrivate · $3.5BSierra and Hippocratic AI Healthcare Agents do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; smaller scale (private).3 of 7 capabilitiesShared product typeSmaller scaleCompareKHK HealthPrivate · $380M raisedChannels and PatientGPT do comparable work on customer support; both also serve buyers who need to handle customer support conversations; similar scale (private).1 of 7 capabilitiesShared product typeCompareVSVerint SystemsAcquiredInsights and Verint Quality Bot both serve buyers who need to watch an AI agent for suspicious or runaway behaviour; Verint Systems is acquired, with no independent scale.5 of 7 capabilitiesShared product typeCompareAAdaPrivateChannels and Ada AI Agent do comparable work on customer support; both also serve buyers who need to handle customer support conversations; Ada's scale not recorded.1 of 7 capabilitiesShared product typeCompareEElevenLabsPrivate · $11BChannels and ElevenLabs Agents do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; same layer and the same scale band (late-stage private).3 of 7 capabilitiesShared product typeSame scale bandCompareAHAssort HealthPrivate · $1.2BSierra and Assort Concierge do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; smaller scale (private).3 of 7 capabilitiesShared product typeSmaller scaleCompareMMicrosoftPublic · $3.7TOverlaps on agent orchestration, customer support, data analysis and 3 more; larger scale (public).6 of 7 capabilitiesShared product typeLarger scaleCompareYYandexPublicChannels and Yandex SpeechSense do comparable work on customer support; both also serve buyers who need to handle customer support conversations; Yandex's scale not recorded.5 of 7 capabilitiesShared product typeCompareUUniphorePrivate · $2.5BOverlaps on agent orchestration, customer support, data analysis and 2 more; smaller scale (private).5 of 7 capabilitiesShared product typeSmaller scaleCompareKKlaviyoPublic · $5.5BChannels and Klaviyo Customer Agent do comparable work on customer support; both also serve buyers who need to handle customer support conversations; smaller scale (public).2 of 7 capabilitiesShared product typeSmaller scaleCompareSSpeakPrivate · $162M raisedChannels and Speak for Business do comparable work on voice agent; similar scale (private).1 of 7 capabilitiesShared product typeCompareRRespeecherPrivate · $4M raisedSierra and Respeecher Text-to-Speech API do comparable work on voice agent; both also serve buyers who need to create synthetic voice and audio; similar scale (private).1 of 7 capabilitiesShared product typeCompareMMoveworksAcquiredOverlaps on agent orchestration, data analysis, text generation and 1 more; Moveworks is acquired, with no independent scale.4 of 7 capabilitiesShared product typeCompareDDXPrivateInsights and AI Code Insights both serve buyers who need to watch an AI agent for suspicious or runaway behaviour; DX's scale not recorded.4 of 7 capabilitiesShared product typeCompareAAlphabet (Google)Public · $4.2TChannels and Gemini Enterprise for Customer Experience do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; larger scale (public).7 of 7 capabilitiesShared product typeLarger scaleCompareDDuolingoPublic · $7.3BChannels and Duolingo Max do comparable work on voice agent; smaller scale (public).2 of 7 capabilitiesShared product typeSmaller scaleCompareFRFurhat RoboticsPrivateSierra and FurhatAI do comparable work on voice agent; both also serve buyers who need to create synthetic voice and audio; Furhat Robotics's scale not recorded; ships platform and robot rather than the same layer.2 of 7 capabilitiesDifferent layerCompareAApplePublic · $4.6TChannels and Siri AI do comparable work on voice agent; larger scale (public).2 of 7 capabilitiesShared product typeLarger scaleCompareAAlvariaPrivateChannels and Alvaria Intelligence Platform (AIP) do comparable work on customer support; Alvaria's scale not recorded; ships platform rather than the same layer.2 of 7 capabilitiesDifferent layerCompareRRunwayPrivate · $5.3BChannels and Runway Characters do comparable work on voice agent; smaller scale (private).2 of 7 capabilitiesShared product typeSmaller scaleCompareNCNAVER CloudPrivateChannels and CLOVA AiCall do comparable work on customer support and voice agent; both also serve buyers who need to handle customer support conversations; NAVER Cloud's scale not recorded.4 of 7 capabilitiesShared product typeCompareEEvenUpPrivate · $2BSierra and EvenUp Communication Agents do comparable work on voice agent; smaller scale (private).2 of 7 capabilitiesShared product typeSmaller scaleCompareDDataikuPrivate · $3.7BOverlaps on agent orchestration, data analysis, evaluation and observability and 1 more; smaller scale (private).4 of 7 capabilitiesShared product typeSmaller scaleCompareUUiPathPublic · $7.2BOverlaps on agent orchestration, data analysis and workflow automation; smaller scale (public).3 of 7 capabilitiesShared product typeSmaller scaleCompareTTypefacePrivateOverlaps on agent orchestration and workflow automation; Typeface's scale not recorded.2 of 7 capabilitiesShared product typeCompareHAHume AIPrivateOverlaps on data analysis, evaluation and observability and voice agent; Hume AI's scale not recorded.3 of 7 capabilitiesShared product typeCompareFAFiddler AIPrivate · $100M raisedInsights and Fiddler Continuous Evaluations both serve buyers who need to watch an AI agent for suspicious or runaway behaviour; similar scale (private).2 of 7 capabilitiesShared product typeCompareCCartesiaPrivateSierra and Sonic / Ink both serve buyers who need to create synthetic voice and audio; Cartesia's scale not recorded; ships API service rather than the same layer.Different layerCompareHCHuawei CloudPrivateChannels and Question Answering Bot (QABot) do comparable work on customer support; both also serve buyers who need to handle customer support conversations; Huawei Cloud's scale not recorded.2 of 7 capabilitiesShared product typeCompareBByteDancePrivateOverlaps on agent orchestration, data analysis, evaluation and observability and 2 more; larger scale (private).5 of 7 capabilitiesShared product typeCompareTTencentPublic · $510.1BSierra and Tencent Cloud Agent Development Platform do comparable work on customer support; both also serve buyers who need to handle customer support conversations; larger scale (public).4 of 7 capabilitiesShared product typeLarger scaleCompareNNotionPrivate · $11BOverlaps on agent orchestration, text generation and workflow automation; same layer and the same scale band (late-stage private).3 of 7 capabilitiesShared product typeSame scale bandCompareSSplunkAcquiredInsights and Splunk Observability Cloud both serve buyers who need to watch an AI agent for suspicious or runaway behaviour; Splunk is acquired, with no independent scale.3 of 7 capabilitiesShared product typeCompareRAResemble AIPrivateChannels and Security Awareness Training do comparable work on voice agent; Resemble AI's scale not recorded.1 of 7 capabilitiesShared product typeCompareHHarveyPrivate · $11BOverlaps on agent orchestration and evaluation and observability; same layer and the same scale band (late-stage private).2 of 7 capabilitiesShared product typeSame scale bandCompareMAMistral AIPrivate · $13.8BChannels and Mistral Speech do comparable work on voice agent; same layer and the same scale band (late-stage private).2 of 7 capabilitiesShared product typeSame scale bandCompareMMercorPrivate · $20BInsights and Mercor Enterprise Evals both serve buyers who need to watch an AI agent for suspicious or runaway behaviour; ships data service rather than the same layer.1 of 7 capabilitiesDifferent layerSame scale bandCompareCAContextual AIPrivate · $100M raisedOverlaps on agent orchestration and workflow automation; similar scale (private); ships API service, agent platform and 1 more rather than the same layer.2 of 7 capabilitiesDifferent layerCompareDDeepgramPrivate · $1.3BSierra and Deepgram Voice Agent API do comparable work on voice agent; smaller scale (private); ships API service rather than the same layer.2 of 7 capabilitiesDifferent layerSmaller scaleCompareSESamsung ElectronicsPublic · $1.2TChannels and Bixby do comparable work on voice agent; larger scale (public).2 of 7 capabilitiesShared product typeLarger scaleCompareGGensparkPrivate · $645M raisedOverlaps on agent orchestration, data analysis and workflow automation; similar scale (private).3 of 7 capabilitiesShared product typeCompareRRobinhoodPublic · $108.6BOverlaps on agent orchestration; larger scale (public).1 of 7 capabilitiesShared product typeLarger scaleCompareCClayPrivate · $319M raisedOverlaps on agent orchestration and data analysis; similar scale (private).2 of 7 capabilitiesShared product typeCompareWWriterPrivate · $1.9BOverlaps on agent orchestration, text generation and workflow automation; smaller scale (private).3 of 7 capabilitiesShared product typeSmaller scaleCompareCCopy.aiAcquired ($13.9M deal)Overlaps on agent orchestration, data analysis and workflow automation; Copy.ai is acquired, with no independent scale.3 of 7 capabilitiesShared product typeCompareEElasticPublic · $10.2BInsights and Elastic LLM Observability both serve buyers who need to watch an AI agent for suspicious or runaway behaviour; similar scale (public).4 of 7 capabilitiesShared product typeCompareDDatadogPublic · $84.9BOverlaps on agent orchestration, data analysis, evaluation and observability and 1 more; larger scale (public).4 of 7 capabilitiesShared product typeLarger scaleCompareAAArthur AIPrivate · $62.7M raisedInsights and Arthur both serve buyers who need to watch an AI agent for suspicious or runaway behaviour; similar scale (private).2 of 7 capabilitiesShared product typeCompareGGlean (Glean Technologies)Private · $7.2BOverlaps on agent orchestration and workflow automation; smaller scale (private).2 of 7 capabilitiesShared product typeSmaller scaleCompareZZscalerPublic · $30.5BOverlaps on evaluation and observability; similar scale (public).1 of 7 capabilitiesShared product typeCompareSASarvam AIPrivate · $275M raisedChannels and Sarvam Voice Agents do comparable work on voice agent; similar scale (private).3 of 7 capabilitiesShared product typeCompareAIApplied IntuitionPrivate · $15BOverlaps on agent orchestration and evaluation and observability; ships platform rather than the same layer.2 of 7 capabilitiesDifferent layerSame scale bandCompareSSpeechmaticsPrivateSierra and Voice Agent API do comparable work on voice agent; both also serve buyers who need to create synthetic voice and audio; Speechmatics's scale not recorded.2 of 7 capabilitiesShared product typeCompareAAArize AIPrivateOverlaps on agent orchestration, data analysis and evaluation and observability; Arize AI's scale not recorded.3 of 7 capabilitiesShared product typeCompareSASnorkel AIPrivate · $1.3BOverlaps on agent orchestration; smaller scale (private); ships agent platform, data service and 1 more rather than the same layer.1 of 7 capabilitiesDifferent layerSmaller scaleCompareVVercelPrivate · $9.3BOverlaps on agent orchestration and evaluation and observability; similar scale (private).2 of 7 capabilitiesShared product typeCompare

Closest alternatives are pairs a vendor page itself compares. Similar products are matched from what each product does; nothing in that group is asserted as a rivalry.

Sources

Total funding

News reporting · 4 May 2026

TechFundingNews reported Sierra's September 2025 $350M round brought its total to $635M; a TechCrunch article reports an additional $950M Series E in May 2026 on top of that — $635M + $950M = $1.585B.

Valuation

News reporting · 4 May 2026

$950M at a $15.8B post-money valuation, TechCrunch 2026-05-04; CNBC reported the same round the same day. Read 2026-08-27.

Employees

News reporting · Jun 2026

Forbes company profile for Sierra, "Employees" stated as of June 2026. Read 2026-08-27.

Founded

Third-party database · 11 Sep 2026

"founded in 2023 by Bret Taylor and Clay Bavor." No Wikipedia article; CNBC coverage blocked to fetch.

Open Sierra in the directory

Something wrong here? Send a correction — quote this company id: sierra.