A few months ago, I shared that Wix Harmony, our AI-powered website creation experience, is now running on a model we developed ourselves. And today, I'm proud to share that Base44, which joined Wix in June 2025, has become the first app-creation platform (vibe coding) in the world to launch its own proprietary LLM “Base 1”.

This isn't a story about two separate teams independently arriving at the same conclusion. It's a story about what becomes possible when you bring Wix and Base44 together. 

Both teams built their own models, and they did it for the same reason. When you own the model, you control your own quality, your own costs, and your own pace of improvement. You stop being a passenger.

Why we built our own Wix model

Our model is built to do one thing: create Wix Harmony websites. And because it specializes in website creation, it does it exceptionally well. It's faster, it produces fewer errors, and the results are significantly better than what we got from external models.

The frontier models are genuinely remarkable. What they've achieved is incredible, and we use and admire them. But they're built to do everything for everyone, trained on across the internet and optimized for breadth.

We understand our corner of the world better than anyone else can. We have an extraordinary amount of rich, specific, real-world feedback from millions of people building real websites every single day. We know how our users behave, what they're trying to build, where they get stuck, and how they can succeed. We have two decades of knowledge of creating every website you can imagine. 

When we own the model, we can act on that feedback. Not quarterly, not tied to a major release cycle, but daily. The pace of improvement is entirely in our hands.

And yes, the cost is much less than what we were spending on external models. That's a structural change to our business.

Base44: from AI-powered platform to full-stack AI company

When we acquired Base44, we didn't just acquire a brilliant product. We acquired a vision that mirrors our own.

Maor Shlomo and the Base44 team have done something remarkable: they've become the first app-creation platform to launch a proprietary LLM, and they did it fast.

The model was fine-tuned using tens of millions of real user interactions on the platform, the kind of high-quality, domain-specific data that most organizations simply don't have access to. The result is a general-purpose AI agent capable of handling complex multi-turn conversations, coding, tool usage, runtime management, and backend operations.

This is a capable production-grade model already serving users.

As Maor said: "Having our own model means we can continue to improve it over time, making us less dependent on external vendors. This is not a trivial effort. It requires deep expertise, significant infrastructure, and access to the kind of rich, diverse data that most organizations simply do not have."

He's right. And together, Wix and Base44 have all three.

This was made possible because Base44 could lean on Wix's industry-leading data science team, the same team that trained the Wix Harmony model applying those hard-won learnings to a new domain. That's the power of this combination.

Base44 didn't have to build this capability from scratch; they had access to years of deep expertise, proven infrastructure, and robust experimentation pipelines the moment they joined Wix. Wix has an industry-leading data science team that has been working together for years, conducting extensive research in AI, machine learning, and model optimization, giving us the depth of expertise needed to build, train, and continuously improve proprietary models at this level.

This was made possible because Base44 could lean on this team, the same team that trained Wix Harmony's model, applying those hard-won learnings to a new domain. In collaboration with top inference providers, and robust experimentation pipelines, we have the foundation for something that will keep getting better, fast.

Why this matters, beyond the technical achievement

Building your own model is hard. It requires talent, infrastructure, data, and conviction. Most companies don't attempt it because the path to "good enough" with an external vendor is much shorter. But "good enough" is a ceiling.

Beyond the sheer scale of resources needed, building a model is an exercise in deep complexity. It demands mastery across a wide range of highly specialized disciplines  from advanced mathematics and statistics, to machine learning research, systems engineering, and large-scale distributed computing. Teams need to navigate intricate architectural decisions, optimize training pipelines, manage numerical instability, and fine-tune countless hyper-parameters, often with limited feedback loops and unpredictable outcomes. The knowledge required isn't just broad; it's cutting-edge, constantly evolving, and rarely found in one place. This is the kind of expertise that takes years to develop and is extremely difficult to hire, retain, and coordinate at the level required to build something truly competitive.

When you own your model stack, you own your roadmap. You decide what to optimize for. You move at your own speed. You're not waiting for a third party to prioritize your use case in their next release. You improve for your users, with your data, on your timeline and our first results are already really exciting to me. 

There is also a meaningful financial dimension here. Compute and inference costs are one of the largest cost drivers in any AI-native business. Owning the model creates a direct and powerful lever to manage those costs, not by cutting corners, but by building smarter and more efficiently. For Base44, this translates to a significant improvement in gross margins. For Wix as a whole, it reinforces our ability to scale our AI capabilities sustainably.

What comes next

When I look at what we've accomplished, a custom model powering Wix Harmony, and now Base44's proprietary LLM in production, I see more than two technical milestones. 

We are becoming a company that doesn't just use AI. We build it. We shape it. We own it.

I've said before that we are living through the most significant shift in how companies are built since the invention of modern programming languages. The companies that will thrive in this era won't be the ones that consume AI as a commodity. They'll be the ones that develop it with depth, focus, and a relentless commitment to the people they serve.

At Wix, we are building that kind of company.