Zernio WhatsApp API - One API for WhatsApp: messaging, calling, and AI agents
You knew Zernio as the API for social media. Now it does WhatsApp too, the whole thing.
Connect a number and you've got the entire WhatsApp Business API behind it: messaging and broadcasts, in-chat forms, calls you can route to AI agents, chatbots, group chats, and numbers in 53 countries. Whatever you need to build on WhatsApp, it's one integration.
Made for developers and the agents they build: REST, SDKs, CLI, and a hosted MCP server.
Official WhatsApp Business API. Zero markup on usage.
Replies
I really think Zernio is an absurdly efficient solution. Since I met them a few months ago when they were still Late, I fell in love with them and their products, and now I’m building solutions with them. This new integration with WhatsApp is definitely going to remove a lot of headaches for those of us who work with WhatsApp agents.
Zernio
@sebastianparracom your feedback means a lot to the whole team! thank you 😍
"Not can you send a message, but the whole thing" nails it, Miki. I build on the Meta WhatsApp Business API directly and sending was never the hard part. The pain is the BSP gatekeeping, number verification, template approval, and the 24h customer-care window that quietly kills any real automation. Routing calls to AI agents on the same number is the dream. Genuine question: how do you handle the 24h window and template approval? That's where every WhatsApp build actually breaks. Congrats on the launch.
Zernio
@david_marko thank you! On the 24h window: Zernio enforces this at the API level. Free-form messages inside the window, while approved template required to reopen outside. The Inbox API tracks conversation state so your agent always knows where it stands before sending.
On templates: there's a full Templates API to create, submit for Meta review, and use immediately once approved, without touching Meta Business Suite. You can also import templates you've already got approved elsewhere
Kim Personal Health Assistant
Congrats on your launch. The thing I'd want to understand as someone building a product on top of this: if each of MY customers needs their own WhatsApp number connected, how painful does that get at scale? Can I wrap Embedded Signup into my own onboarding so a non-technical customer connects their WABA in a few taps, or does it always route through Meta's flow? Multi-tenant provisioning is usually where WhatsApp infra falls over. Great launch regardless.
Zernio
@second_son_of_god it's actually pretty clean. You call one endpoint to get an auth URL, redirect your customer to it, they pick or create their WABA in a few taps, and get sent back to your redirect URL with the account ID appended. So from your product's side it's just a redirect.
Strong launch. WhatsApp is one of those surfaces where the guardrail matters as much as the API call.
For agent workflows, I’d want a pre-send state check: window open or closed, template required, last inbound timestamp, and handoff owner. Are you planning that as a helper, or leaving it to builders?
Zernio
@blah_mad thank you! Right now that's builder's responsibility
Looks promising! How do you handle Whatsapp calling, given that Meta only enables Whatsapp Calling API for numbers with 2000+ unique messages a month?
Zernio
@peter_neyra Hey Peter,
Thanks, glad it's looking promising.
On WhatsApp calling: We support inbound + outbound voice calls via the official Meta WhatsApp Business Calling API (VoIP). You can route calls to a phone line, SIP endpoint, AI voice agent, or custom webhook.
We handle the plumbing (webhooks for call events, routing logic, status tracking) so you don't have to fight Meta's docs directly.
Been using Zernio since they were "Late.dev". Great and reliable service and excellent customer support. However, the recent and massive price hike has forced me to look for alternative services. I would really love to continue using Zernio but the new pricing structure completely killed the financial viability of doing so. :(
Zernio
@concept211 Appreciate the honest feedback - and thanks for sticking with us since the Late.dev days. Means a lot.
The new pricing is pay-per-connected-account, graduated, with everything included. First 2 accounts free, then $6 for 3–10, $3 for 11–100, down to $1 for 101–2,000. No tiers, no add-ons, no feature gating.
Old pricing had rigid tiers that forced upgrades just to unlock features like analytics, DMs, or ads; punishing teams as they grew.
Why we made the change
Matches real usage: Most of you embed Zernio into products where end-user accounts scale.
Rewards growth instead of penalizing it (price/account drops as you add more).
Predictable & fair: Pay only for what you connect. Disconnect anytime.
Covers the real costs of maintaining 15+ official platform integrations, partnerships, reliability (99.7%+), MCP/agent tools, compliance, and absorbing all platform changes; all while staying bootstrapped.
This is better aligned with builders and long-term viability. At scale it's cheaper than alternatives with broader coverage. Feedback like this helps us tune it further.
For teams who are already using Twilio for Whatsapp - is it easy to migrate from Twilio to Zernio? Is it a drop in replacement or does it need a full rebuild of existing workflows?
Zernio
@pradyumna6 Hey Pradyumna,
Good question: lots of teams are asking this right now with our WhatsApp launch.
Short answer: It's mostly a drop-in replacement for the WhatsApp side, not a full rebuild. Your Meta assets (WABA, templates, phone numbers) transfer over, and the migration is usually hours to a couple days depending on how custom your workflows are.
The first integration is never the problem. It's the ongoing maintenance (API changes, quota fights, token refreshes, surprise billing) that eats engineering time.