I turned my solo project-mapping app into a platform overnight — here's what I learned building the first plugin myself

I'm Manu, solo dev building UluP Spaces (visual project mapping — nodes instead of a flat task list). Last night I shipped v4.0: a public REST API, rate limiting, HMAC-signed webhooks, and a community plugin directory.
The API itself wasn't the hard part. What I underestimated was this: an empty plugin directory convinces no one. So instead of announcing "you can build on this now" and waiting, I built the first plugin myself, the same night — Quick Capture, a Chrome extension that saves any web page as a node in one click. Open source, MIT licensed. Building it as an actual third-party client (not just testing the API with curl) immediately surfaced a bug I never would have found otherwise: a redirect between my apex domain and www that silently dropped the auth header. Worked fine in my own testing, broken for any real client. Fixed now, but it's a good reminder — if you're opening up an API, build something against it yourself before you tell anyone else to.
Biggest lesson: shipping the API is not the milestone. Someone building something you didn't imagine is the milestone. Having the first plugin live on day one is what makes the directory feel real instead of empty.

Docs: ulupstudio.com/developers
Plugin directory: ulupstudio.com/plugins