# How to build a SaaS with GPT-6 Astra

> Source: <https://www.augmentedswe.com/p/build-saas-with-gpt-6-astra>
> Published: 2026-10-14 11:02:44+00:00

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.