June ‘25
Where it started: social posting
One API to publish on TikTok, Instagram, Facebook, YouTube, LinkedIn, X and Threads.
Your agent could post. Now it can run ads, text, and call too
Social, ads, inbox, WhatsApp, SMS and calls, behind one Zernio API key.
Built for products and AI agents.
Over the past months, Zernio grew from a social media API into marketing infrastructure for products and their agents, available through one API, a CLI and an MCP server.
It now covers social, ads, inbox, WhatsApp, SMS and calls, so your product and the agents behind it can reach customers and hear back from them on every channel, without stitching together a stack of vendors. Today we're making it official.
If you already build on Zernio, nothing changes in how you work: same API key, same webhooks, same docs. And social isn't going anywhere. It's still our biggest product, and we keep building on it every week.
How we got here
We launched as Late in 2025 with one goal. Connecting a social platform shouldn't mean a new OAuth app, a review queue and a month of work, so we manage that work for you and let you skip it.
More than 13 million posts later, the teams building on Zernio looked different than when we started: AI marketing platforms, agencies running 100+ client accounts from one tool, and products with their own inbox, ads and WhatsApp agents.
The pattern was the same across all of them. Social was solved, but every other channel meant another vendor and another integration. So, channel by channel, we took the same approach to the rest of the stack.
- June ‘25
- August ‘25
- November ‘25
- December ‘25
- January ‘26
- February ‘26
- March ‘26
- May ‘26
- June ‘26
- July ‘26
- August ‘26
- September ‘26
- Today
August ‘25
Analytics API
Likes, comments, shares, reach and views from every platform, through one endpoint.
November ‘25
Inbox API
Comments and DMs from every platform in one feed. Our first step from posting to conversations.
December ‘25
Our first MCP
Claude and other AI agents can run Zernio. Your agent became a Zernio user too.
January ‘26
Telegram and Reddit join in
Two more networks, same API.
February ‘26
Ads API
Create and manage paid campaigns across 7 networks, through official integrations.
March ‘26
Late becomes Zernio
New name and look. Same API, team and infrastructure.
May ‘26
WhatsApp API
Our first messaging channel beyond social. Full WhatsApp support, and #2 Product of the Day on Product Hunt.
June ‘26
Phone numbers, SMS and calls
Buy numbers, send texts and make calls via API. Ready for your AI voice agents.
June ‘26
Our first team offsite
Turning your ideas and ours into what Zernio is today.
July ‘26
ChatGPT Ads
Launch campaigns inside ChatGPT from the same Ads API.
August ‘26
We reached $3M ARR
Reached together with you building on Zernio. Thank you!
September ‘26
iMessage
Send and receive iMessages via API, from your product or your agents.
Today
One API for all of it
Social was the start. Now Zernio is how products and their agents reach customers, on every channel.
Today, more than 200,000 engineers and founders build on Zernio, and what you build goes well beyond what "social media API" stands for.
“We're now at the level where we're thinking, this is actually pretty good to have in our platform. But as soon as clients ask for more, I know with Zernio we can add those things quickly.”
What runs through Zernio
In our first year, we tracked one number mostly: posts published. Then you started building more on top of Zernio, and new numbers started climbing.
Posting across social platforms is still the biggest line on the chart and it's still growing, but it's no longer the only one. Everything below already runs through Zernio every week, so the infrastructure under your product is ready for whatever you grow into.
13M+Posts published
3M+Messages sent every week
12K+Ad accounts connected
Spending$600MA year between them
3K+Numbers live
One Zernio key, a whole marketing stack
Reaching customers usually takes five or six integrations: a social API, each ad platform, a WhatsApp provider, a telco for SMS and calls, and something to collect the replies. Each comes with its own auth, review process and bill.
With Zernio, it's one integration. Every channel shares the same key, webhooks and data format. So a post, an ad, a message and a call can all be part of one flow in your product.
Unified inbox
Social DMs, WhatsApp, iMessage and SMS replies land in one feed. Answer from your product, or let your agent handle it.
Explore Unified Inbox
Messaging & Calls
Get a number in 54 countries and use it to message, send updates and call your customers, with recording and transcription built in.
Explore Phone Numbers
Social
Publish, schedule and measure performance across 16 platforms, all from inside your product. Where Zernio started, and still our biggest product.
Explore Social Media API
Advertise
Launch campaigns and track spend and results on every major ad platform, from Meta to OpenAI, as part of your product or your agent's routine.
Explore Ads APIGive your AI agent the keys
Agents can already write a good post or message. What they can't do alone is send it, reply to the comments under it, or follow up with the people who clicked.
Connect our MCP server or CLI, and your agent gets 490+ tools to act for you. It can build the integration into your product, launch a campaign sequence, and purchase the number to talk with your customers.
We handle the parts no agent should have to deal with: OAuth, app reviews, carrier registration, expired tokens and rate limits. So the work doesn't stop halfway.
More of the work between products and their customers will be done by agents. They need infrastructure that runs without a human fixing it. We'd like Zernio to be what it calls.
Meet the new Zernio
If you're already building on us, there's nothing to migrate. WhatsApp, SMS, calls, ads, and the MCP server all work with the key you have today.
If you're new, you can go from signup to your first post, message, or call in minutes.