Sierra alternatives (2026)

Built around multi-agent "teams" with a transparent dual meter.

The most hands-off "AI employee" with voice/phone, if you want done-for-you.

11x sells autonomous "digital workers" for go-to-market teams. Alice is an AI SDR that runs outbound prospecting end to end (lead research and enrichment from 50+ sources, ICP matching, and multi-channel sequencing across email, LinkedIn, SMS and phone), while Julian handles inbound voice and chat qualification.

Fin (by Intercom) is an AI agent for customer service that resolves support conversations end-to-end across chat, email, voice and social. It can run standalone on top of an existing helpdesk (Zendesk, Salesforce, Freshdesk, Zoho Desk and others) or bundled inside Intercom's own platform.

Enterprise AI customer service platform branded "the AI concierge for every customer." It deploys AI agents across chat, email, and voice, configured with natural-language Agent Operating Procedures (AOPs) instead of code. Used by large brands like Notion, Duolingo, Eventbrite, and Rippling to deflect and fully resolve high support volume.

Developer-first voice AI platform for building, testing, and deploying low-latency phone and voice agents. Vapi orchestrates speech-to-text, an LLM, and text-to-speech behind one API, handling telephony, turn-taking, interruptions, and tool calling so you wire in your own providers.

Retell AI is a developer-friendly AI voice agent platform for automating inbound and outbound phone calls. It bundles speech-to-text, a proprietary low-latency turn-taking model (~600ms), TTS, LLM orchestration, telephony, batch calling and post-call analytics into one usage-based stack you can run via a no-code dashboard or API.

Enterprise AI voice-agent platform that automates inbound and outbound phone calls 24/7 on Bland's own proprietary, vertically integrated stack (LLM, real-time STT, premium TTS/voice cloning, and telephony all in-house). Built for high-volume teams that need sub-second latency, full call observability, and SOC 2 / HIPAA / PCI compliance.

No-code platform for building and deploying AI customer-support agents trained on your own data, deployable across website chat, WhatsApp, Slack, email, and voice/telephony. Agents resolve tickets, take actions via API (AI Actions), and escalate to a human when they hit their limits.

AI customer service agent ("the AI agent customers want to talk to") that resolves support questions using your own help content and knowledge base, with a claimed 67% average automation rate. Lyro Actions let it perform autonomous tasks like checking order status, starting returns, updating accounts, and qualifying leads, and it can connect to your CRM, billing, or database over MCP.

Enterprise-ready, no-code AI voice agent platform for automating inbound and outbound phone conversations at scale. Positions as an end-to-end Voice AI platform with in-house telephony, a visual flow designer, and 200+ integrations across CRM, calendar, and helpdesk tools.

No-code chat marketing automation platform for building AI-assisted chatbots and automated conversation flows across Instagram DM, Facebook Messenger, WhatsApp, TikTok, SMS, and email from one interface. Trigger-based flows (comments, story replies, keywords, links) turn social engagement into captured leads and sales conversations.

Enterprise AI agent platform for customer service, pairing a multi-model AI engine with on-the-ground local deployment teams to run multilingual voice, chat, and email agents that resolve customer requests at human level across 30+ markets. Sales-led and deployment-heavy, it reports an 80% resolve rate handling tens of thousands of requests a day.

"The AI Front Office for Home Services," an always-on AI workforce for service businesses (HVAC, plumbing, electrical, and other trades) that answers every inbound call, text, and chat, qualifies urgency, checks technician availability, and books jobs straight into ServiceTitan or Housecall Pro 24/7. It also runs outbound re-engagement campaigns and scores CSR calls for coaching.

AI Customer Concierge built for complex, regulated companies like fintech and healthtech. Unlike basic deflection chatbots, Lorikeet resolves end-to-end support issues across chat, email, SMS, WhatsApp, and voice by following the same multi-step workflows and judgment your human agents use, taking actions like refunds, billing changes, and account updates.