If anyone doesn't know Eager was the company Adam Schwartz and I founded in 2014 which became the current version of Cloudflare Apps.
The challenges are probably pretty obvious, you have to take this codebase and application which were meant to live on its own and conform it to the way another system works. In the process you have to adapt your deployment, auth, style, etc. to work in this alternative reality. At times it can seem like you spend months working just to get back to the feature set you started with. At others you get to see the vision of an integration you sketched on a whiteboard six months ago become reality and you're blown away that this crazy idea could ever actually work. The definition of 'you' also changed a lot in that process, we went from being a small team to getting support and assistance from dozens of passionate people. It's a very different world where your resources can scale to your vision, instead of having to compromise what you want to build at every turn.
Particularly when you work at a company with as sweeping a vision as Cloudflare, you also get a chance to expand your vision itself. At Eager it was a romantic dream to think we would get on a hundred thousand sites. With our launch today we reach six million. The idea of a $100mm apps fund, or having 60 apps in the store before we even launched, were not things which startup-Eager could have pulled off.
My biggest surprise is gonna be a little silly but it's it's when someone builds a really great app without any help or guidance. As much work as you put into the API or docs it's always a little shocking when someone builds something from scratch on the platform you work on every day, and it works well, out of the box.