Short answer — pick a true “omnichannel” CX/helpdesk platform (SaaS or API-first) that matches your team size and needs. Good, widely used choices are Twilio Flex (highly customizable API-first contact center), Freshworks/Freshdesk + Freshchat (easy omnichannel out of the box, strong Meta integrations), Zendesk Sunshine Conversations (unified messaging API + Zendesk Suite), Intercom (in‑app + messaging-first, good automation), and Salesforce Service Cloud (enterprise scale + CRM + messaging/Einstein AI). See vendor notes and links below to compare. (twilio.com)

What to look for (quick checklist)

• Channels supported: WhatsApp Business, Instagram DM, Facebook Messenger, SMS, email, webchat/in-app, voice, RCS/Apple Messages for Business (if you need them).
• Unified inbox / threading across channels so customers don’t repeat themselves.
• Bots / automation & LLM support (bot handoff to humans).
• CRM / e‑commerce integrations (Salesforce, HubSpot, Shopify, Zendesk, etc.).
• Compliance & data residency (HIPAA, PCI, regional rules).
• Pricing model: per‑agent seat + per‑message/channel fees (WhatsApp templates often billed separately).
• Developer/API needs vs out‑of‑the‑box product: choose API-first if you’ll build custom routing/UIs.

Vendor shortlist & who each is best for

• Twilio Flex — API‑first, highly customizable contact center. Best when you need custom routing, custom UI, or want to embed many channels and voice with full developer control. Good for mid → large teams that can build. (twilio.com)
• Freshworks (Freshdesk / Freshchat) — omnichannel inbox with ready integrations for WhatsApp, Instagram, Google Business Messages and bot automation; fast to deploy and good for mid‑market. Strong out‑of‑box messaging features thanks to Freshworks Neo. (freshworks.com)
• Zendesk + Sunshine Conversations — Sunshine gives a unified messaging API to build once and deploy across channels; Zendesk Service Suite adds enterprise ticketing, reporting and agent tools. Good for businesses that want a messaging platform plus mature support workflows. (zendesk.com)
• Intercom — excellent for product‑led companies that want in‑app chat, outbound messaging and conversational workflows; supports WhatsApp and other channels as paid add‑ons. Great for startups and SMBs focused on in‑product support and growth. (intercom.com)
• Salesforce Service Cloud — enterprise scale, deep CRM integration and AI (Einstein) with official WhatsApp / messaging integrations for large orgs that need unified data and automation across service/marketing/sales. (salesforce.com)
• LivePerson — strong conversational AI and enterprise messaging platform (bots + human handover, multi‑channel). Good for brands running large automation + human agent programs. (liveperson.com)
• Front, Help Scout, Gorgias — Front (shared inbox, lots of channel support) and Help Scout (simple shared inbox + social channels) are great for small → mid teams wanting simple workflows; Gorgias is tailored to e‑commerce (Shopify) merchants. (front.com)
• Messaging API / channel providers (MessageBird, Vonage, etc.) — if you only need to connect channels (WhatsApp, SMS, RCS) to your own stack or to a lightweight inbox, these providers supply the channel connectivity and numbers. Remember message pricing and template rules (WhatsApp template vs 24‑hour window). (messagebird.com)

Costs & channel rules (brief)

• Expect two cost types: (1) platform/agent seats (monthly/annual) and (2) channel/message fees (WhatsApp templates, SMS carrier fees). WhatsApp template and customer service window policies can materially affect cost — confirm current rates with your provider. (api.support.vonage.com)

Quick recommendation by situation

• If you need full control and will build custom UI/workflows: Twilio Flex or Sunshine Conversations (with in‑house devs). (twilio.com)
• If you want fast deployment + Meta channel integrations + bots: Freshworks (Freshdesk/Freshchat). (freshworks.com)
• If you’re product-led or SMB wanting in‑app + chat automation: Intercom or Help Scout. (intercom.com)
• If you’re enterprise with CRM centrality and AI needs: Salesforce Service Cloud. (salesforce.com)
• If you’re ecommerce (Shopify) and want a tight merchant workflow: Gorgias. (gorgias.com)

Suggested pilot plan (30–60 days)

1. Pick 2 platforms that match your tech/size (one low-effort SaaS and one API-first if you may build).
2. Run a focused pilot (select 1–2 channels customers use most; e.g., WhatsApp + webchat or Instagram + email). Test threading, bot handoffs, SLAs and reporting.
3. Measure CSAT, handle time, unresolved volume, and integration pain (CRM, order system).
4. Confirm messaging costs (WhatsApp/SMS) and legal/compliance requirements before roll‑out.

If you want a tailored short list, tell me three facts (company size or agents, must‑have channels, and whether you have developer resources) and I’ll return a ranked 2–3 vendor shortlist with pros/cons and what to test in a pilot.