About
I’m Jay (John Costallos). I’m a product manager by day, and Jay’s Foundry is where I build things at night.
I have a development background, drifted into product management, and never stopped wanting to get my hands on the tools. The Foundry is my dedicated space for that. One laptop, its own accounts, its own workflows, completely separate from everything else in my life. I wrote about why I set it up that way and what the operating model looks like in Treating My Side Projects Like a Product.
Why “the Foundry”?
The name comes from the idea that this is where things get forged. Tools, content, skills, maybe eventually products. “Foundry” felt right because it implies heat and effort and raw material becoming something useful. It’s not a studio. It’s not a lab. It’s a place where you make things.
What you’ll find here
I write about building with AI-native tools, applying product thinking to personal projects, and the actual experience of figuring out agentic workflows as a solo builder. Some posts are short observations. Some are longer walkthroughs. All of them are honest about the path, not just the result. If something took three tries, you’ll hear about the first two.
The stack
This blog runs on Astro, deploys to Vercel, and gets authored in Notion. A GitHub Actions pipeline handles publishing.