# 12 Best Sierra Alternatives (2026)

> 12 verified Sierra alternatives in Voice AI, led by Decagon. Compared on real production cost and per-use-case verdicts. Updated August 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.

## Where to switch, by reason

| Switching because of | See |
| --- | --- |
| price at production volume | [Replicant](https://www.versusref.com/voice-ai/best/agency/) |
| compliance requirements | [Pipecat](https://www.versusref.com/voice-ai/best/healthcare/) |
| deeper pipeline control | [LiveKit Agents](https://www.versusref.com/voice-ai/best/developer/) |
| outbound campaign tooling | [Cognigy (NiCE)](https://www.versusref.com/voice-ai/best/outbound/) |
| an out-of-the-box receptionist | [Telnyx Voice AI Agents](https://www.versusref.com/voice-ai/best/receptionist/) |
| ecommerce order handling | [Dentina](https://www.versusref.com/voice-ai/best/ecommerce/) |

## The Sierra alternatives, ranked

| # | Tool | Positioning | vs Sierra | Best if you need | Price | Rating |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | [Decagon](https://www.versusref.com/voice-ai/tools/decagon/) | AI concierge platform - voice/chat/email agents driven by natural-language Agent Operating Procedures (AOPs). | vs Sierra: ~25% more languages. | no-code agency deploys, outbound sales campaigns, smb receptionist and booking | See pricing |  |
| 2 | [Abby Connect](https://www.versusref.com/voice-ai/tools/abby-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/mo |  |
| 3 | [Air AI](https://www.versusref.com/voice-ai/tools/air-ai/) | AI sales calls |  |  | See pricing |  |
| 4 | [Alex (fka Apriora)](https://www.versusref.com/voice-ai/tools/alex/) | '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 pricing |  |
| 5 | [Arini](https://www.versusref.com/voice-ai/tools/arini/) | The AI front desk for dental groups and DSOs - zero missed calls, 24/7. |  |  | See pricing |  |
| 6 | [ASAPP](https://www.versusref.com/voice-ai/tools/asapp/) | Generative AI CX platform whose GenerativeAgent overlays existing CCaaS stacks to automate voice and messaging interactions. |  |  | See pricing |  |
| 7 | [Assort Health](https://www.versusref.com/voice-ai/tools/assort-health/) | Specialty-specific AI agents for the full patient journey (access, intake, referrals, outreach). |  |  | See pricing |  |
| 8 | [Avoca](https://www.versusref.com/voice-ai/tools/avoca/) | AI workforce platform for the home-services trades (voice, chat, outbound, and call coaching). |  |  | See pricing |  |
| 9 | [Bland AI](https://www.versusref.com/voice-ai/tools/bland/) | Outbound-heavy, enterprise-leaning | vs Sierra: ~25% fewer languages, adds native sip trunking. |  | From $0.14/min |  |
| 10 | [Bolna](https://www.versusref.com/voice-ai/tools/bolna/) | 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/min |  |
| 11 | [Brooke.ai](https://www.versusref.com/voice-ai/tools/brooke-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 pricing |  |
| 12 | [Caseflood](https://www.versusref.com/voice-ai/tools/caseflood/) | '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 pricing |  |
| 13 | [Cognigy (NiCE)](https://www.versusref.com/voice-ai/tools/cognigy/) | 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 pricing |  |
| 14 | [ConverzAI](https://www.versusref.com/voice-ai/tools/converzai/) | 'World's Leading Automation for Staffing Firms' - agentic virtual recruiters covering the pipeline from sourcing to placement, staffing-agency (not corporate HR) focus. |  |  | See pricing |  |
| 15 | [Cresta](https://www.versusref.com/voice-ai/tools/cresta/) | Generative AI platform unifying autonomous AI Agent, Agent Assist, and Conversation Intelligence for enterprise contact centers. | vs Sierra: about half the languages. |  | See pricing |  |
| 16 | [Dasha](https://www.versusref.com/voice-ai/tools/dasha/) | Dev platform, conversational AI |  |  | From $0.08/min |  |
| 17 | [Deepgram Voice Agent API](https://www.versusref.com/voice-ai/tools/deepgram-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/min |  |
| 18 | [Dentina](https://www.versusref.com/voice-ai/tools/dentina/) | The AI dental receptionist built by a dentist - 24/7 inbound/outbound calls with real-time PMS write-back. |  |  | From $299/mo |  |
| 19 | [Dialzara](https://www.versusref.com/voice-ai/tools/dialzara/) | Lowest-entry-price SMB AI receptionist with minute-bundle pricing and SMS/chatbot/outbound add-ons |  |  | From $0.48/min |  |
| 20 | [Dograh](https://www.versusref.com/voice-ai/tools/dograh/) (OSS) | 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 pricing |  |
| 21 | [Domu](https://www.versusref.com/voice-ai/tools/domu/) | YC S24 collections-automation platform for financial institutions across the Americas - 'compliance is not a checkbox, it is the architecture'. |  |  | See pricing |  |
| 22 | [echowin](https://www.versusref.com/voice-ai/tools/echowin/) | No-code AI phone/chat agent builder with pay-as-you-go pricing, 70+ languages, and agency white-label options | vs Sierra: ~25% more languages. |  | From $0.20/min |  |
| 23 | [ElevenLabs Agents](https://www.versusref.com/voice-ai/tools/elevenlabs-agents/) | Voice-quality leader, agents platform | vs Sierra: ~25% more languages. |  | From $0.05/min |  |
| 24 | [EliseAI](https://www.versusref.com/voice-ai/tools/eliseai/) | 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 pricing |  |
| 25 | [Google Gemini Live API](https://www.versusref.com/voice-ai/tools/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/min |  |
| 26 | [Goodcall](https://www.versusref.com/voice-ai/tools/goodcall/) | Agentic voice AI for SMB service businesses; unusual per-unique-customer metering with unlimited minutes ('born at Google'). |  |  | From $79/mo |  |
| 27 | [Guava (formerly Gridspace)](https://www.versusref.com/voice-ai/tools/guava/) | Developer-first voice agent API 'for regulated industries', built on a decade of Gridspace voice AI in banks and hospitals. |  |  | See pricing |  |
| 28 | [HappyRobot](https://www.versusref.com/voice-ai/tools/happyrobot/) | 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 pricing |  |
| 29 | [Hello Patient](https://www.versusref.com/voice-ai/tools/hello-patient/) | Conversational AI for healthcare's 'front door' - voice, SMS, and chat patient communication. |  |  | See pricing |  |
| 30 | [Hume EVI](https://www.versusref.com/voice-ai/tools/hume-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/min |  |
| 31 | [Kore.ai](https://www.versusref.com/voice-ai/tools/kore-ai/) | Enterprise agentic AI platform (Artemis) with voice AI agents for contact-center self-service at Global 2000 scale. |  |  | See pricing |  |
| 32 | [Level AI](https://www.versusref.com/voice-ai/tools/level-ai/) | LLM-native contact-center intelligence platform (QA/Agent Assist center of gravity) with an AI Virtual Agent for voice and chat automation. |  |  | See pricing |  |
| 33 | [Liberate](https://www.versusref.com/voice-ai/tools/liberate/) | '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 pricing |  |
| 34 | [Lindy](https://www.versusref.com/voice-ai/tools/lindy/) | AI employees incl. phone agents | vs Sierra: adds bring-your-own llm. |  | From $49.99/mo |  |
| 35 | [LiveKit Agents](https://www.versusref.com/voice-ai/tools/livekit-agents/) (OSS) | Realtime infra + agents (OSS + cloud) | vs Sierra: adds native sip trunking. |  | From $0.01/min |  |
| 36 | [Loman AI](https://www.versusref.com/voice-ai/tools/loman/) | Restaurant voice AI with deep POS order-writing (Toast/Square/Clover/Olo etc.) - orders and payments, not just reservations and FAQs. |  |  | See pricing |  |
| 37 | [Millis AI](https://www.versusref.com/voice-ai/tools/millis/) | Low-latency voice agents | vs Sierra: ~2× the languages, adds native sip trunking. |  | From $0.02/min |  |
| 38 | [Frontdesk (My AI Front Desk)](https://www.versusref.com/voice-ai/tools/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/min |  |
| 39 | [Netic](https://www.versusref.com/voice-ai/tools/netic/) | Autonomous AI revenue engine for essential home services. |  |  | See pricing |  |
| 40 | [Numa](https://www.versusref.com/voice-ai/tools/numa/) | 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 pricing |  |
| 41 | [Observe.AI](https://www.versusref.com/voice-ai/tools/observe-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 pricing |  |
| 42 | [Omilia](https://www.versusref.com/voice-ai/tools/omilia/) | Conversational AI platform for contact-center voice/IVR automation, with native 'Lexis' voice synthesis and agentic voice/chat agents. |  |  | See pricing |  |
| 43 | [OpenAI Realtime API](https://www.versusref.com/voice-ai/tools/openai-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 pricing |  |
| 44 | [Parloa](https://www.versusref.com/voice-ai/tools/parloa/) | AI Agent Management Platform (AMP) for enterprise contact centers - design, test, scale, optimize agentic AI. | vs Sierra: adds bring-your-own llm. |  | See pricing |  |
| 45 | [Patter](https://www.versusref.com/voice-ai/tools/patter/) (OSS) | 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 pricing |  |
| 46 | [Phonely](https://www.versusref.com/voice-ai/tools/phonely/) | SMB AI receptionist | vs Sierra: adds native sip trunking. |  | From $0.05/min |  |
| 47 | [Pipecat](https://www.versusref.com/voice-ai/tools/pipecat/) (OSS) | 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/min |  |
| 48 | [Play.ai (PlayHT)](https://www.versusref.com/voice-ai/tools/play-ai/) | Voice agents + TTS heritage |  |  | See pricing |  |
| 49 | [PolyAI](https://www.versusref.com/voice-ai/tools/polyai/) | Enterprise voice assistants | vs Sierra: about half the languages, adds native sip trunking. |  | See pricing |  |
| 50 | [Rapida](https://www.versusref.com/voice-ai/tools/rapida/) (OSS) | 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/min |  |
| 51 | [Regal](https://www.versusref.com/voice-ai/tools/regal/) | Contact-center AI (enterprise) |  |  | See pricing |  |
| 52 | [Replicant](https://www.versusref.com/voice-ai/tools/replicant/) | Voice-native contact-center automation with deterministic reasoning for business rules and 1B+ minutes of production conversation data. |  |  | See pricing |  |
| 53 | [Retell AI](https://www.versusref.com/voice-ai/tools/retell/) | API plus no-code, production telephony fast | vs Sierra: adds native sip trunking. |  | From $0.07/min |  |
| 54 | [Ringly.io](https://www.versusref.com/voice-ai/tools/ringly/) | Ecommerce phone agents | vs Sierra: ~25% fewer languages, adds native sip trunking. |  | From $0.29/min |  |
| 55 | [Rosie](https://www.versusref.com/voice-ai/tools/rosie/) | 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/mo |  |
| 56 | [Salient](https://www.versusref.com/voice-ai/tools/salient/) | 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 pricing |  |
| 57 | [Sameday](https://www.versusref.com/voice-ai/tools/sameday/) | 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/mo |  |
| 58 | [Simple Phones](https://www.versusref.com/voice-ai/tools/simple-phones/) | Done-for-you AI phone agent for small businesses on flat per-call-bundle pricing | vs Sierra: about half the languages. |  | From $97/mo |  |
| 59 | [Sindarin](https://www.versusref.com/voice-ai/tools/sindarin/) | Persona-driven voice agents |  |  | From $99/mo |  |
| 60 | [Slang AI](https://www.versusref.com/voice-ai/tools/slang-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/mo |  |
| 61 | [Smith.ai](https://www.versusref.com/voice-ai/tools/smith-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/mo |  |
| 62 | [STELLA Automotive AI](https://www.versusref.com/voice-ai/tools/stella-automotive/) | Dealership-focused conversational AI platform with certified DMS integrations (CDK, Reynolds, Tekion) and dealer/industry investors incl. Reynolds & Reynolds board representation. |  |  | See pricing |  |
| 63 | [Synthflow](https://www.versusref.com/voice-ai/tools/synthflow/) | No-code, agency white-label king | vs Sierra: about half the languages, adds native sip trunking. |  | From $2,500/mo |  |
| 64 | [Telnyx Voice AI Agents](https://www.versusref.com/voice-ai/tools/telnyx-voice-ai/) | 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/min |  |
| 65 | [TEN Framework](https://www.versusref.com/voice-ai/tools/ten-framework/) (OSS) | 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 pricing |  |
| 66 | [Thoughtly](https://www.versusref.com/voice-ai/tools/thoughtly/) | No-code AI contact center | vs Sierra: ~40% fewer languages, adds native sip trunking. |  | From $500/mo |  |
| 67 | [Toma](https://www.versusref.com/voice-ai/tools/toma/) | "AI Coworkers for the Automotive Enterprise" - dealership call automation with production safeguards, YC/a16z-backed. |  |  | See pricing |  |
| 68 | [Twilio ConversationRelay](https://www.versusref.com/voice-ai/tools/twilio-conversationrelay/) | Carrier-grade voice harness for BYO-LLM agents inside Twilio Programmable Voice. | vs Sierra: adds native sip trunking. |  | From $0.07/min |  |
| 69 | [Ultravox](https://www.versusref.com/voice-ai/tools/ultravox/) | Realtime speech model + platform | vs Sierra: about half the languages, adds native sip trunking. |  | From $0.05/min |  |
| 70 | [Upfirst](https://www.versusref.com/voice-ai/tools/upfirst/) | Per-call-bundle AI receptionist with 35+ languages and declining overage rates up to 600 calls/mo | vs Sierra: ~35% fewer languages. |  | From $24.95/mo |  |
| 71 | [Vapi](https://www.versusref.com/voice-ai/tools/vapi/) | Dev-first API platform, full pipeline control | vs Sierra: adds native sip trunking. |  | From $0.05/min |  |
| 72 | [Vision Agents](https://www.versusref.com/voice-ai/tools/vision-agents/) (OSS) | 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 pricing |  |
| 73 | [Vocode](https://www.versusref.com/voice-ai/tools/vocode/) (OSS) | Open-source framework | vs Sierra: adds native sip trunking. |  | See pricing |  |
| 74 | [Voiceflow](https://www.versusref.com/voice-ai/tools/voiceflow/) | Agent builder (chat + voice) | vs Sierra: adds bring-your-own llm. |  | From $0.05/min |  |
| 75 | [Zoom Virtual Agent Receptionist](https://www.versusref.com/voice-ai/tools/zoom-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/mo |  |

## 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 (Outbound sales campaigns):** 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](https://www.versusref.com/voice-ai/decagon-vs-sierra/)

**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](https://www.versusref.com/voice-ai/decagon-vs-sierra/) · [Decagon review](https://www.versusref.com/voice-ai/tools/decagon/)

### 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](https://www.versusref.com/voice-ai/tools/abby-connect/)

### 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](https://www.versusref.com/voice-ai/tools/alex/)

### 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](https://www.versusref.com/voice-ai/tools/arini/)

Source: https://www.versusref.com/voice-ai/alternatives/sierra/