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
Zernio
Hey Product Hunt! I’m Miki, founder of Zernio :)
We built Zernio as a social media API. One integration, 10+ platforms, and developers could ship social features without spending months on OAuth flows and platform-specific quirks. That part worked.
But we kept getting the same question: what about WhatsApp?
Not “can you send a message”, but the whole thing. Numbers, broadcasts, calling, in-chat forms, group chats, AI agents. People were building real products on WhatsApp and the existing options were either expensive BSPs with markups on every message, or raw Meta APIs that take weeks to months to set up.
So we built it properly.
Connect a number, get the entire WhatsApp Business API behind it. Same Zernio integration developers already know. Zero markup on usage, you pay exactly what Meta charges per message sent, and Zernio monthly subscription. REST, SDKs, CLI, and a hosted MCP server if you’re building with AI agents.
We’re 7 people in Spain. Bootstrapped. We’ve been shipping one WhatsApp feature a day this week and today felt like the right moment to bring it to Product Hunt.
We’ll be in the comments all day. Happy to go deep on anything, like how number provisioning works inside Zernio, how to manage templates, or how the pricing compares to Twilio, whatever you’re curious about 🤝
PicWish
@paletmiki nice launch guys! how does zernio's hosted mcp server setup compare to running a custom adapter when hooking this up to an ai agent workflow?
Zernio
@mohsinproduct The advantage of our MCP is that it's 0 setup, but you can always build one yourself if you want more control :)
@paletmiki The easiest way to connect to all the platforms by far!!! This team rocks 🚀🤘
Zernio
@david_alarcon1 thank you, means a lot!
One of the most interesting launches today! And a good call on the whatsapp calling angle as this is the part nobody else is really shipping. QQ - how are you guys handling the 24h customer service window? I trust once it closes an agent cant reopen the thread without an approved template. Does the MCP surface that state back to the agent?
Zernio
@artstavenka1 That's right! Only templates after 24 hours. We surface this
Zernio
@artstavenka1 thank you and a great question! Zernio treats the WhatsApp 24‑hour window the same way Meta does: within that window you can send any messages; outside it you must use an approved template.
on MCP: the agent has access to full conversation history and timestamps via the Inbox API, so it can calculate whether the window is still open. There's also a message.failed webhook with the Cloud API error code if a free-form message gets rejected, so agents can catch it reactively too.
Just recently started using Zernio, but it works great and was super simple to set up!
Zernio
@ryan_hale1 Thank you so much!! Feedback like this means the world to us.
Zernio
@ryan_hale1 glad to welcome you and thank you for the support! ☺️
Congrats! I tried your platform and the setup was smooth, good docs too
Zernio
@jojoh thank you! The docs are something I'm really proud of too (commenting as a marketer who gets them 😄)
Zernio
@jojoh Thank you, George! Feedback is really appreciated 😊
Zernio
@jojoh thanks!
Zernio
Hi PH community! Darya here, the marketer behind this launch.
I joined Zernio 3 months ago. Two weeks back Miki said "let's do a feature week for WhatsApp." the team said 'yes' without fully knowing what that meant for our calendars 😅
So we shipped. Workflows on Monday, phone numbers in 53 countries on Tuesday, calling API on Wednesday, Flows on Thursday. And today we're here on Product Hunt. Watching our team build in real time has been something. Seven people, bootstrapped, just shipping. So if you have any questions about the launch, the product, or how we pulled this week off (without tears) I'm here all day!!
Tabstack by Mozilla
🐐
Zernio
@dasha_nazarova1 🐐🚀
Hey, I have started using Zernio and it's so smooth to integrate and work flawlessly!
Zernio
@rohan27s thank you! smooth and flawless is exactly what we're going for 😎
@paletmiki WhatsApp is a strong surface for agents because it is already where a lot of real customer conversations happen. The important part is making the API reliable enough for handoffs, approvals, and context history — not just sending and receiving messages.
Zernio
@alpertayfurr exactly! and handoffs, webhooks to a system, and context history are all part of workflows now 🙌
the "zero markup on usage" line got me. dealing with Twilio's WhatsApp pricing on top of Meta's fees was killing margins on a project last year. having messaging, calls, and AI agent routing all in one integration without the markup games is exactly what i would've wanted. the MCP server being hosted is a nice touch for agent workflows too. curious how you're handling rate limits when multiple AI agents are hitting the same number concurrently?
Zernio
@rnagulapalle thank you! we handle everything from our side so rate limits don't bite you
I was going to post something like "great product" or "congrats on the launch"… but I've known the Zernio team for a while and always admired how they work, so I mean this: I already loved what they were doing on social, but folding in the full WhatsApp Business API is another level.
Having it all in one place (messages, broadcasts, group chats, even routing calls to AI agents) takes a ton off your plate.
Congrats on the launch. If you're building anything on WhatsApp, take a look. Probably the best API out there.
Zernio
@jacinto_fleta Jacin this feedback genuinely make our day 😍 appreciate your support!
Congrats on the launch Miki and team! Dealing with the official Meta API for WhatsApp is usually a nightmare, and the existing BSPs always take a huge cut per message. Love that you guys are offering the raw Meta pricing with zero markup. Definitely giving this a try for my next project!
Zernio
@davidtroton thanks a lot for support!