The rise of AI services companies like Invisible and Palantir, which build custom on-prem solutions, marks a reversal of the standardized cloud SaaS trend. Enterprises now prioritize proprietary, custom AI applications to gain a competitive edge.

Despite the hype, LinkedIn found that third-party AI tools for coding and design don't work out-of-the-box on their complex, legacy stack. Success requires deep customization, re-architecting internal platforms for AI reasoning, and working in "alpha mode" with vendors to adapt their tools.

Wix develops its own AI models for its Base44 product primarily to improve quality by training on its vast, specific user data. This creates a superior user experience compared to generic frontier models. The cost savings are a secondary benefit and are not as dramatic as often perceived.

Frustration with a mediocre, AI-lacking vendor drove the decision to build a custom replacement, even when a commercial option existed. This signals a major vulnerability for incumbent SaaS players who fail to innovate with AI, as customers may choose to build rather than renew.

The key for enterprises isn't integrating general AI like ChatGPT but creating "proprietary intelligence." This involves fine-tuning smaller, custom models on their unique internal data and workflows, creating a competitive moat that off-the-shelf solutions cannot replicate.

Specialized SaaS companies like Writer and Intercom are moving beyond simply wrapping OpenAI or Anthropic APIs. They are now training their own foundation models to create more defensible, vertically-integrated AI products, signaling a shift away from platform dependency toward bespoke AI stacks.

Building effective agents requires intensive, custom work for each client—data cleansing, training, and deployment by skilled engineers. Large incumbents lack the agility and cost structure to provide this bespoke service, creating an opening for focused startups who can afford the human capital.

Off-the-shelf AI support tools lack the deepest context for accurate answers, which is often found only in a company's proprietary source code (e.g., how interest is calculated). Klarna built its own system so its AI could directly access this 'source of truth,' making support a core part of its tech stack.

While building a custom support agent might be cheaper than using a service like Intercom's Fin, the primary advantage is customizability. Building your own allows for creating highly specific skills and integrating a wider range of tools to make the agent more powerful.