Here are enterprise-grade platforms that let you manage WhatsApp, Facebook Messenger and email (plus other channels) from one place — short summary of how each supports those three channels and when they’re a good fit.

• Twilio (Conversations / Flex + SendGrid) — full programmable CPaaS: supports WhatsApp and Facebook Messenger via Conversations/APIs and provides email via SendGrid; good if you need developer-first, highly customizable omnichannel flows and integration into apps/CRMs. (twilio.com)

• MessageBird (Inbox) — omnichannel inbox + APIs: native Inbox connects WhatsApp and Messenger and brings email into a single agent workspace; strong for teams that want a managed inbox with low-code builders. (messagebird.com)

• Zendesk (Support / Sunshine Conversations) — unified agent workspace: Zendesk routes email, Facebook Messenger and WhatsApp (via Sunshine Conversations / Conversations APIs and partner apps) into Agent Workspace; good if you want ticketing + omnichannel support at scale. (zendesk.com)

• Freshworks / Freshdesk Omni (Freshchat) — omnichannel support inbox: Freshdesk Omni / Freshchat supports email, WhatsApp and Facebook and offers bot automation and routing in one inbox; fits teams wanting easy setup and integrated bots. (freshworks.com)

• Front — shared inbox / workspace: native integrations for email, Facebook Messenger and WhatsApp (native or via Twilio) so teams handle all messages in one collaborative inbox; great for companies that want email-first shared inbox UX plus messaging. (front.com)

• Vonage (formerly Nexmo) — Messages / Conversations APIs: single API to send/receive WhatsApp and Facebook Messenger and integrates with email/conversation flows; good for developer-led omnichannel messaging with fallback/failover logic. (vonage.com)

• Intercom — Conversations inbox with add‑ons: Intercom supports Facebook Messenger and has a paid WhatsApp channel (integrates into the Intercom inbox) while email is part of its Conversations inbox; good when you want conversational sales/service with automation. (intercom.com)

• LivePerson (Conversational Cloud) — omnichannel conversational platform: supports WhatsApp, Facebook Messenger and email channels in its agent/automation workspace; strong for large enterprises focused on AI+human blended conversations. (liveperson.com)

• Khoros — enterprise social & messaging care: supports Facebook Messenger and WhatsApp as part of Khoros Care (with integrations for email/other channels); focused on large brands and social-first customer care. (developer.khoros.com)

• HubSpot (Conversations inbox) — built-in conversations inbox: HubSpot’s Conversations can connect email and Facebook Messenger, and supports WhatsApp Business connections (via native or marketplace integrations); good when you want CRM-native omnichannel support. (knowledge.hubspot.com)

Important implementation notes (enterprise considerations)

• WhatsApp setup: most platforms require a Meta Business Account / WhatsApp Business Account and business verification (or working with a BSP). Plan for phone-number registration, template approvals and the Meta verification process. (developers.facebook.com)
• WhatsApp pricing and templates: Meta changed WhatsApp pricing to a per-message/template model (rolled out in 2024–2025); check each vendor’s markup and template‑message costs. (developers.facebook.com)
• Two approaches: (1) API/CPaaS vendors (Twilio, Vonage, MessageBird) for custom flows and scale; (2) Inbox/support vendors (Zendesk, Freshworks, Front, Intercom, LivePerson, Khoros, HubSpot) for agent workflows, ticketing, bots and less custom dev work. Choose by whether you prioritize developer flexibility or a ready agent workspace. (twilio.com)
• Security & compliance: for enterprise, confirm SOC 2 / ISO / data residency, message retention, and encryption handling with the vendor and any BSP they use. (Vendors’ compliance pages will show certifications.)

If you want, I can:

• narrow this to 3 best fits based on whether you prefer "low-code inbox", "developer-first API", or "CRM-native", and include estimated pricing/enterprise plan notes; or
• create a short feature checklist (templates, billing, SLA, bot support, CRM integrations) you can use to evaluate vendors.