It's hard.
- They support 400 different models, 80 different providers, and an unlimited number of new custom agents. Every single model, provider, and agent, has its own weirdness that has to be accounted for. Tool calls change by model. Effort changes by model. Backend APIs (messages, responses, etc) change by provider. There are thousands of specific tweaks, fixes, hacks, that need to be implemented to make this thing "just work". And you have to keep updating it all, weekly.
- On top of that, they support providers running in multiple countries, which increases the legal, logistical, financial, and networking complexity.
- On top of that, they need to figure out pricing and deals with providers, and ensure the providers allocate the necessary networking and compute capacity. They need to work with providers directly to troubleshoot and fix all kinds of issues, from networking to application.
- On top of that, they implement multiple kinds of request routers. An auto router to route your request to the best general model, a fusion model to attempt the request on multiple models and pick the best response, a pareto router to route requests to the best coding model for your request.
- On top of that, they build custom features that businesses and users want, like Data Loss Prevention (which I'm blown away they actually provide for free). Lots of very useful business functionality for managing not only what model and provider to use, but also limits on usage, filters, etc. They also implement SSO, prompt injection guardrails, logging/auditing, workspaces, etc.
- On top of that, you have to be very good at just implementing HTTP APIs. Most people aren't good at it. API design is hard, HTTP is way more complicated than it seems, network traffic shaping is a black art.
- On top of that, running applications and infrastructure, and scaling it 10x every year, is a subtle yet critical skill. No matter how good your code is, it's pointless without working hardware/running apps.
- On top of that, they provide a generous free tier, which has to be subsidized, and is probably only partially subsidized by providers.
Why pay for this rather than build one? Because there's no sense in building one. There's a reason restaurants don't build their own factories to manufacture their own pots and pans. Their business isn't selling pots and pans, it's selling people cooked steak. It's a bad idea to waste time, effort, and money trying to make things you aren't going to sell.