Short answer — best-in-class options depend on your use case. Pick from these leaders by category:

Omnichannel contact-center & enterprise conversational AI

• Genesys Cloud — full contact-center with embedded conversational AI, predictive routing, agent copilot and voice + digital omnichannel. (genesys.com)
• LivePerson — enterprise Conversational Cloud focused on messaging, orchestration and BYO‑LLM deployment. Good when you need scale + vendor-managed conversational orchestration. (liveperson.com)
• Talkdesk — AI contact‑center platform with agentic AI, automatic summarization and no‑code automation tools for voice + digital. (talkdesk.com)
• Five9 — contact-center platform with conversational AI/IVA and GenAI tooling for customer automation. (five9.com)

Support suites with built-in messaging & bots (good for blended ticketing + chat)

• Zendesk Messaging / Zendesk Suite — strong ticketing + messaging, easy agent handoff and AI agents for triage. (zendesk.com)
• Intercom — product‑centric messenger + bots for customer support and in‑app conversations; good for SaaS/product workflows. (intercom.com)
• Freshdesk / Freshworks (Freddy AI) — omnichannel support suite with AI agents, copilot and fast time‑to‑value for standard support workflows. (freshworks.com)

No‑code / self‑service conversational bots (fast deployment, high containment)

• Ada — strong no‑code AI agents for self‑service across web, messaging and WhatsApp; enterprise grade and multilingual. (adaglobal.com)
• Solvvy — focused on intelligent self‑service / knowledge‑driven chatbots to deflect tickets and automate FAQs. (developers.solvvy.com)

Developer / open‑source & custom platforms (maximum control)

• Rasa — open‑source, pro‑code conversational framework for teams that want full control and on‑prem / private deployments. (opensource.rasa.com)
• Botpress — developer-focused platform to build production AI agents with LLMs and custom logic. (botpress.com)
• Microsoft Bot Framework / Azure Bot Service — enterprise developer tooling that integrates with LUIS, Azure Cognitive Services and Azure contact‑center stacks. (azure.microsoft.com)

LLMs & AI building blocks (for custom agents, voice, or advanced copilot features)

• OpenAI platform (Responses / Realtime / Assistants APIs) — flexible, low‑latency multimodal APIs (text + voice) used to power conversational agents and copilot features. Use these when you need best-in-class LLM capabilities. (openai.com)

How to choose (quick checklist)

• Primary channel(s): voice + phone, web chat, WhatsApp, SMS, in‑app? (Pick contact‑center vendors for voice + scale; pick Ada/Intercom/Freshdesk for messaging-first.)
• Level of control: prefer no‑code vs pro‑code / on‑prem? (No‑code → Ada, Solvvy, Intercom; Pro‑code → Rasa, Botpress, Azure.)
• Integrations: must connect CRM/OMS/ERP/workflow tools? Verify native connectors (Zendesk, Salesforce, Shopify, etc.). (ada.cx)
• AI trust & governance: need data residency, PII redaction, model‑governance? Favor vendors that advertise enterprise security and governance features (Genesys, Five9, LivePerson, Rasa Pro). (genesys.com)
• Containment goals & metrics: target ticket deflection %, resolution time, CSAT — run a pilot to measure ROI.

Recommendation by common use case

• Small business / simple web chat: LiveChat, Tidio or Olark for fast, low‑cost setup. (livechat.com)
• SaaS / product‑led support: Intercom or Zendesk (in‑app messaging + product context). (intercom.com)
• E‑commerce with high WISMO volume: Ada or Freshdesk (Freddy) for high containment + Shopify/OMS integrations. (ada.cx)
• Large enterprise contact center (voice + digital at scale): Genesys, Talkdesk, Five9, LivePerson. Run vendor POCs for voice accuracy and routing performance. (genesys.com)
• Full customization / data privacy needs: Rasa or Botpress + an LLM provider (OpenAI, Anthropic, or private models) hosted per your compliance needs. (opensource.rasa.com)

Suggested next steps (practical)

• Define 2–3 success metrics (containment rate, avg. handle time, CSAT) and a 30–90 day pilot scope.
• Run a hands‑on POC with real traffic on 1–2 vendors (one no‑code, one pro‑code if applicable). Most vendors provide trial accounts or sandbox demos. (zendesk.com)
• Test escalation handoffs (bot → human), data sync with your CRM/OMS, and measure false positives/negatives in intent detection.
• Validate security/compliance (SOC2, ISO, HIPAA if needed) and data retention / model training policies before production.

If you want, tell me: your company size, main channels (web chat, WhatsApp, phone), and priority (speed to deploy vs customization vs compliance). I’ll suggest a 2‑vendor short list and a focused pilot plan with metrics and timeline.