How to build a SaaS with GPT-6 Astra

A developer built Hearth, a home maintenance SaaS app, from project scoping through MVP implementation in under one hour using GPT-6 Astra inside the Codex AI-coding assistant, without hitting usage limits on OpenAI's $20/month plan. The app is a React application built with Stripe and Cloudflare, and the developer says Astra handled planning, design, architecture and implementation, with similar results expected in Cursor and OpenCode. The walkthrough argues that cheap model intelligence now makes it reasonable to let AI make many product decisions, though explicit instructions or a PRD still yield more reliable results.

GPT-6 Astra is insane. It’s been a minute since we’ve used AI to build an app from scratch, so I figured we’d start one today You can use Astra in many AI-coding assistants. Today’s tutorial will use Codex https://www.augmentedswe.com/t/codex , but you’ll have a similar experience in Cursor https://www.augmentedswe.com/t/cursor and OpenCode https://www.augmentedswe.com/p/how-to-use-opencode . I did my project scoping, planning, and implementation of MVP in less than one hour, all without hitting usage limits on the OpenAI $20/mo plan. Read on to see how. What we’re going to use AI to build Lately I’ve been wishing there was a good , minimal app to keep track of home maintenance and projects. There’s a few decent options already, but nothing that fit what I was looking for perfectly. But since we’re in the middle of “the decade of agents,” I could just build exactly what I wanted. Here’s the landing page for Hearth, the home maintenance SaaS that I built with GPT-6 Astra in Codex. Astra helped me plan, design, architect, and build the entire app. It’s a React app with Stripe & Cloudflare, and I’ll show you how I used AI to do the whole thing. If you want to use AI to build your own apps, you’re obviously in the right spot. I spend dozens of hours researching each of these guides so you have a shortcut to building software with AI. I’d love to have you join us and get notified when we share more tutorials like this. Planning out the project in plan mode When I first started using AI to build software, I perceived it to be a bit dumb, because it was You can look at tutorials from last year and see that I give explicit advice to not start using AI until you know exactly what you want. I won’t give that advice anymore. As we move towards intelligence too cheap to meter, it becomes more and more reasonable to let AI make tons of the decisions. The advice I give in Using AI to Plan a New App https://www.augmentedswe.com/p/how-to-use-ai-to-plan-a-new-app is still worthwhile. If you know exactly what you want, you should give explicit instructions, maybe even a PRD. You can even use AI to help you draft your PRD, and you’ll still get more reliable results.