12 Best Sierra Alternatives (2026)

Sierra is ai agents that handle a company's customer service conversations across phone, chat, email, and messaging.. Teams that switch usually cite price at production volume, compliance requirements, deeper pipeline control, outbound campaign tooling, an out-of-the-box receptionist, ecommerce order handling. The alternatives below are ranked by published head-to-head verdicts, not sponsorship.

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Reviewed by vsref Editorialfacts verified Aug 20, 2026Methodology →

Where to switch, by reason

Switching because of price at production volume →see Replicant

Switching because of compliance requirements →see Pipecat

Switching because of deeper pipeline control →see LiveKit Agents

Switching because of outbound campaign tooling →see Cognigy (NiCE)

Switching because of an out-of-the-box receptionist →see Telnyx Voice AI Agents

Switching because of ecommerce order handling →see Dentina

#1Decagon

AI concierge platform - voice/chat/email agents driven by natural-language Agent Operating Procedures (AOPs).vs Sierra: ~25% more languages.Best if you need: no-code agency deploys, outbound sales campaigns, smb receptionist and booking

See pricingvs Sierra →Try Decagon →

#2Abby Connect

Legacy virtual-receptionist provider (est. 2005) adding a lower-cost AI tier with built-in human backup; minute-bundle pricing on both lines.vs Sierra: about half the languages.

From $99/moTry Abby Connect →

#3Air AI

AI sales calls

See pricingTry Air AI →

#4Alex (fka Apriora)

'Interview everyone. Hire the best.' - autonomous AI interviewer (voice + video) for high-volume hiring, operated by Apriora Inc. dba Alex.vs Sierra: about half the languages.

See pricingVisit Alex (fka Apriora) →

#5Arini

The AI front desk for dental groups and DSOs - zero missed calls, 24/7.

See pricingVisit Arini →

#6ASAPP

Generative AI CX platform whose GenerativeAgent overlays existing CCaaS stacks to automate voice and messaging interactions.

See pricingVisit ASAPP →

#7Assort Health

Specialty-specific AI agents for the full patient journey (access, intake, referrals, outreach).

See pricingVisit Assort Health →

#8Avoca

AI workforce platform for the home-services trades (voice, chat, outbound, and call coaching).

See pricingVisit Avoca →

Bland AI

Outbound-heavy, enterprise-leaningvs Sierra: ~25% fewer languages, adds native sip trunking.

From $0.14/minVisit Bland AI →

#10Bolna

Open-source voice-agent orchestration with a hosted platform priced for Indian-language call volume.vs Sierra: about half the languages, adds bring-your-own llm.

From $0.06/minVisit Bolna →

#11Brooke.ai

OEM-channel digital voice assistant for fixed ops - a sub-brand of Proactive Dealer Solutions (Better Car People), sold through programs like Stellantis MarketCenter rather than as a standalone startup.

See pricingVisit Brooke.ai →

#12Caseflood

'The first human-assisted legal AI intake team designed to autonomously sign retainers for law firms' - long-form voice intake plus human-in-the-loop closing, YC-backed.

See pricingVisit Caseflood →

All 75 voice ai alternatives

#13Cognigy (NiCE)

Agentic AI platform for CX (Cognigy.AI + Voice Gateway); Forrester Wave 2026 Leader, sold standalone and inside NiCE CXone Mpower.vs Sierra: ~2× the languages.

See pricingVisit Cognigy (NiCE) →

#14ConverzAI

'World's Leading Automation for Staffing Firms' - agentic virtual recruiters covering the pipeline from sourcing to placement, staffing-agency (not corporate HR) focus.

See pricingVisit ConverzAI →

#15Cresta

Generative AI platform unifying autonomous AI Agent, Agent Assist, and Conversation Intelligence for enterprise contact centers.vs Sierra: about half the languages.

See pricingVisit Cresta →

#16

Dasha

Dev platform, conversational AI

From $0.08/minVisit Dasha →

#17Deepgram Voice Agent API

Unified STT + LLM orchestration + TTS voice-agent pipeline at a flat all-in rate ($4.50/hr), with BYO-LLM/TTS discounts and enterprise deployment options.vs Sierra: adds bring-your-own llm.

From $0.07/minVisit Deepgram Voice Agent API →

#18Dentina

The AI dental receptionist built by a dentist - 24/7 inbound/outbound calls with real-time PMS write-back.

From $299/moVisit Dentina →

#19Dialzara

Lowest-entry-price SMB AI receptionist with minute-bundle pricing and SMS/chatbot/outbound add-ons

From $0.48/minVisit Dialzara →

#20DograhOSS

Self-hostable open-source voice agent platform ('OSS alternative to Vapi & Retell') with a no-code workflow builder and air-gapped on-prem deployment for regulated industries.vs Sierra: adds bring-your-own llm.

See pricingVisit Dograh →

#21Domu

YC S24 collections-automation platform for financial institutions across the Americas - 'compliance is not a checkbox, it is the architecture'.

See pricingVisit Domu →

#22echowin

No-code AI phone/chat agent builder with pay-as-you-go pricing, 70+ languages, and agency white-label optionsvs Sierra: ~25% more languages.

From $0.20/minVisit echowin →

#23

ElevenLabs Agents

Voice-quality leader, agents platformvs Sierra: ~25% more languages.

From $0.05/minVisit ElevenLabs Agents →

#24EliseAI

Voice-capable agentic suite, not a voice-only agent: full housing-operations platform (leasing, resident services, CRM, payments) plus a HealthAI arm - voice is one channel of a much broader product.vs Sierra: about half the languages.

See pricingVisit EliseAI →

#25Google Gemini Live API

Native-audio speech-to-speech model API (Gemini Live) with barge-in, affective dialog, and tool use over a stateful WebSocket.vs Sierra: ~25% more languages.

From $0.02/minVisit Google Gemini Live API →

#26Goodcall

Agentic voice AI for SMB service businesses; unusual per-unique-customer metering with unlimited minutes ('born at Google').

From $79/moVisit Goodcall →

#27Guava (formerly Gridspace)

Developer-first voice agent API 'for regulated industries', built on a decade of Gridspace voice AI in banks and hospitals.

See pricingVisit Guava (formerly Gridspace) →

#28HappyRobot

Enterprise 'AI operating system for the real economy': AI-worker platform that grew out of logistics voice agents, now spanning 8 verticals (logistics, utilities, airlines, finance, insurance, manufacturing, retail, telecom).

See pricingVisit HappyRobot →

#29Hello Patient

Conversational AI for healthcare's 'front door' - voice, SMS, and chat patient communication.

See pricingVisit Hello Patient →

#30Hume EVI

Emotionally intelligent speech-to-speech API (Empathic Voice Interface, EVI 3 / EVI 4 mini) with voice cloning and supplemental-LLM support.vs Sierra: about half the languages, adds bring-your-own llm.

From $0.07/minVisit Hume EVI →

#31Kore.ai

Enterprise agentic AI platform (Artemis) with voice AI agents for contact-center self-service at Global 2000 scale.

See pricingVisit Kore.ai →

#32Level AI

LLM-native contact-center intelligence platform (QA/Agent Assist center of gravity) with an AI Virtual Agent for voice and chat automation.

See pricingVisit Level AI →

#33Liberate

'The Most Trusted AI in Insurance' - voice-first, insurance-native agents (pre-trained on insurance processes) spanning sales, service, and claims across voice, SMS, email, and digital channels.vs Sierra: about half the languages.

See pricingVisit Liberate →

#34

Lindy

AI employees incl. phone agentsvs Sierra: adds bring-your-own llm.

From $49.99/moVisit Lindy →

#35

LiveKit AgentsOSS

Realtime infra + agents (OSS + cloud)vs Sierra: adds native sip trunking.

From $0.01/minVisit LiveKit Agents →

#36Loman AI

Restaurant voice AI with deep POS order-writing (Toast/Square/Clover/Olo etc.) - orders and payments, not just reservations and FAQs.

See pricingVisit Loman AI →

#37

Millis AI

Low-latency voice agentsvs Sierra: ~2× the languages, adds native sip trunking.

From $0.02/minVisit Millis AI →

#38Frontdesk (My AI Front Desk)

Multi-channel AI front desk (voice/SMS/chat/email/WhatsApp) with bundled CRM and a white-label reseller program, mid-rebrand from My AI Front Desk to Frontdesk

From $0.25/minVisit Frontdesk (My AI Front Desk) →

#39Netic

Autonomous AI revenue engine for essential home services.

See pricingVisit Netic →

#40Numa

AI operating system for the AI-native dealership - voice AI plus agentic follow-up (Heat Case, Opportunity, Service Advisor agents) for franchise dealers and multi-rooftop groups.

See pricingVisit Numa →

#41Observe.AI

Contact-center AI platform expanding from conversation intelligence into autonomous VoiceAI agents (inbound and outbound) with copilots for frontline teams.vs Sierra: about half the languages.

See pricingVisit Observe.AI →

#42Omilia

Conversational AI platform for contact-center voice/IVR automation, with native 'Lexis' voice synthesis and agentic voice/chat agents.

See pricingVisit Omilia →

#43OpenAI Realtime API

Frontier speech-to-speech model API (gpt-realtime family) for low-latency voice agents over WebRTC, WebSocket, and SIP.vs Sierra: adds native sip trunking.

See pricingVisit OpenAI Realtime API →

#44Parloa

AI Agent Management Platform (AMP) for enterprise contact centers - design, test, scale, optimize agentic AI.vs Sierra: adds bring-your-own llm.

See pricingVisit Parloa →

#45PatterOSS

MIT-licensed, self-host-only voice AI SDK (Python + TypeScript) abstracting 27+ providers across LLM/STT/TTS/carrier layers - a middle ground between hosted platforms (Vapi/Retell) and heavyweight frameworks.vs Sierra: adds bring-your-own llm.

See pricingVisit Patter →

#46

Phonely

SMB AI receptionistvs Sierra: adds native sip trunking.

From $0.05/minVisit Phonely →

#47PipecatOSS

Open-source Python framework for real-time voice and multimodal conversational agents, maintained by Daily, with Pipecat Cloud as the managed production runtime.vs Sierra: adds native sip trunking.

From $0.01/minVisit Pipecat →

#48Play.ai (PlayHT)

Voice agents + TTS heritage

See pricingVisit Play.ai (PlayHT) →

#49

PolyAI

Enterprise voice assistantsvs Sierra: about half the languages, adds native sip trunking.

See pricingVisit PolyAI →

#50RapidaOSS

Open-source (GPL-2.0 + branding terms) voice AI orchestration platform in Go/gRPC, aimed at agencies, CPaaS/CCaaS providers, and enterprises wanting white-label, multi-tenant voice operations with provider-level cost passthrough.vs Sierra: adds native sip trunking.

From $0.01/minVisit Rapida →

#51

Regal

Contact-center AI (enterprise)

See pricingVisit Regal →

#52Replicant

Voice-native contact-center automation with deterministic reasoning for business rules and 1B+ minutes of production conversation data.

See pricingVisit Replicant →

#53

Retell AI

API plus no-code, production telephony fastvs Sierra: adds native sip trunking.

From $0.07/minVisit Retell AI →

#54

Ringly.io

Ecommerce phone agentsvs Sierra: ~25% fewer languages, adds native sip trunking.

From $0.29/minVisit Ringly.io →

#55Rosie

Self-serve SMB AI answering service with bundled-minute pricing and bilingual EN/ES on every plan.vs Sierra: about half the languages.

From $49/moVisit Rosie →

#56Salient

Compliance-first AI loan-servicing platform ('Taylor' voice agent plus audit/claims/chargeback agents) for technology-first consumer lenders - voice-as-a-wedge into the full servicing lifecycle.

See pricingVisit Salient →

#57Sameday

Trades-focused AI sales agent - sells and books jobs (claims 92%+ booking rate, voice cloning of your staff) rather than just taking messages.

From $449/moVisit Sameday →

#58Simple Phones

Done-for-you AI phone agent for small businesses on flat per-call-bundle pricingvs Sierra: about half the languages.

From $97/moVisit Simple Phones →

#59

Sindarin

Persona-driven voice agents

From $99/moVisit Sindarin →

#60Slang AI

Hospitality-native voice AI ('Superhost') priced per location - reservation-system depth and guest recognition rather than generic receptionist features.vs Sierra: about half the languages.

From $399/moVisit Slang AI →

#61Smith.ai

Human+AI hybrid receptionist platform with per-call bundle pricing; 500+ live agent network, law-firm-heavy customer base.vs Sierra: about half the languages.

From $150/moVisit Smith.ai →

#62STELLA Automotive AI

Dealership-focused conversational AI platform with certified DMS integrations (CDK, Reynolds, Tekion) and dealer/industry investors incl. Reynolds & Reynolds board representation.

See pricingVisit STELLA Automotive AI →

#63

Synthflow

No-code, agency white-label kingvs Sierra: about half the languages, adds native sip trunking.

From $2,500/moVisit Synthflow →

#64Telnyx Voice AI Agents

Carrier-native voice AI: telephony, GPUs, STT/TTS and orchestration vertically integrated at the network edge.vs Sierra: ~45% more languages, adds native sip trunking.

From $0.05/minVisit Telnyx Voice AI Agents →

#65TEN FrameworkOSS

Open-source real-time multimodal conversational AI framework (voice + video + avatar) with its own VAD and full-duplex turn-detection models, backed by Agora.vs Sierra: adds native sip trunking.

See pricingVisit TEN Framework →

#66

Thoughtly

No-code AI contact centervs Sierra: ~40% fewer languages, adds native sip trunking.

From $500/moVisit Thoughtly →

#67Toma

"AI Coworkers for the Automotive Enterprise" - dealership call automation with production safeguards, YC/a16z-backed.

See pricingVisit Toma →

#68Twilio ConversationRelay

Carrier-grade voice harness for BYO-LLM agents inside Twilio Programmable Voice.vs Sierra: adds native sip trunking.

From $0.07/minVisit Twilio ConversationRelay →

#69

Ultravox

Realtime speech model + platformvs Sierra: about half the languages, adds native sip trunking.

From $0.05/minVisit Ultravox →

#70Upfirst

Per-call-bundle AI receptionist with 35+ languages and declining overage rates up to 600 calls/movs Sierra: ~35% fewer languages.

From $24.95/moVisit Upfirst →

#71

Vapi

Dev-first API platform, full pipeline controlvs Sierra: adds native sip trunking.

From $0.05/minVisit Vapi →

#72Vision AgentsOSS

Open-source multimodal (video-first) AI agent framework by Stream, combining realtime LLMs with vision models on Stream's low-latency edge network.vs Sierra: adds bring-your-own llm.

See pricingVisit Vision Agents →

#73

VocodeOSS

Open-source frameworkvs Sierra: adds native sip trunking.

See pricingVisit Vocode →

#74

Voiceflow

Agent builder (chat + voice)vs Sierra: adds bring-your-own llm.

From $0.05/minVisit Voiceflow →

#75Zoom Virtual Agent Receptionist

Big-tech price anchor for the receptionist segment: standalone AI receptionist at $29.99/mo (100 min), launched 2026-07-09; also bundled free with Zoom Phone.vs Sierra: about half the languages.

From $29.99/moVisit Zoom Virtual Agent Receptionist →

How the top Sierra alternatives compare

Beyond the ranked cards: how the top 4 Sierra alternatives place in the Voice AI field, where each one wins in our published verdicts, and what Sierra still holds over it.

1. Decagon

Among the 31 voice ai tools we track, Decagon has the 4th-widest language coverage - a fit for multilingual and localization projects.

Our use-case verdicts have Decagon ahead of Sierra for no-code agency deploys, outbound sales campaigns and smb receptionist and booking and matches it for healthcare compliance.

Seen from the other side, Sierra vs Decagon: ~20% fewer languages.

Why teams switch: For outbound sales and call-center campaigns, the single most important capability is native outbound campaign support. Decagon explicitly has it while Sierra does not, and that gap alone is decisive for this use case. Both platforms support warm transfer to a human agent, so they are equal on that secondary factor. Concurrency limits and SIP trunking details are unavailable for either platform, so those factors cannot differentiate the two. Decagon also supports 70 languages versus Sierra's 55, giving it broader reach for multilingual outbound campaigns. Outbound sales campaigns verdict →

Overall verdict: Decagon takes 3 of 6 use cases against Sierra's 2, with 1 tie, and the wins are backed by meaningful capability advantages. For no-code agency deploys, Decagon offers a no-code agent builder that lowers the barrier for non-technical teams. For outbound sales campaigns, Decagon provides native outbound campaign support, a feature Sierra does not match. For SMB receptionist and booking, Decagon's 70 supported languages versus Sierra's 55 gives it a clear reach advantage for diverse customer bases. Sierra counters with a simulation and testing suite and outcome-based per-resolution pricing that suits ecommerce and custom pipelines, but those 2 wins fall short of Decagon's breadth. Decagon's $481M total funding also signals strong enterprise momentum.

Full Decagon vs Sierra comparison → · Decagon review →

2. Abby Connect

Among the 31 voice ai tools we track, Abby Connect has the 28th-widest language coverage.

Before switching, weigh what stays behind - Sierra vs Abby Connect: ~28× the languages.

Abby Connect review →

4. Alex (fka Apriora)

Among the 31 voice ai tools we track, Alex (fka Apriora) has the 16th-widest language coverage.

The reverse angle matters too - Sierra vs Alex (fka Apriora): ~2× the languages.

Alex (fka Apriora) review →

5. Arini

Among the 17 voice ai tools we track, Arini has the 6th-lowest latency - a fit for real-time, conversational apps.

Arini review →