# I updated ahastack.dev for htmx 4

> ahastack.dev now runs on Astro 7 and htmx 4, has 18 live demos on Cloudflare, and ships a skill file so coding agents know how to build with the AHA stack.

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2026-09-10 | Topics: [News](https://flaviocopes.com/tags/news/) | Canonical: https://flaviocopes.com/ahastack-update/

I updated [ahastack.dev](https://ahastack.dev), the site about [the AHA stack](https://flaviocopes.com/the-aha-stack/): Astro, htmx and Alpine.js.

The site was written in 2024. Since then Astro went from 4 to 7, and [htmx 4 came out](https://flaviocopes.com/htmx-4/). The demo linked from the site was hosted on Fly.io and had gone offline.

Here's what changed.

## Everything on current versions

The docs now describe Astro 7, htmx 4 and Alpine.js 3.

htmx 4 changed a few things that matter for the stack. Attributes no longer inherit by default. Error responses get swapped into the page. Event names changed. There's a new page, [What's changed since 2024](https://ahastack.dev/aha/6-whats-changed/), that lists all of it.

## 18 live demos

The old demo was one counter. The new one is at [demo.ahastack.dev](https://demo.ahastack.dev) and has 18 small apps.

Counter, active search, todos, inline validation, lazy loading, infinite scroll, sortable table, tabs, who's online, progress bar, guestbook, optimistic like button, modal dialog, cascading selects, bulk actions, error handling, boosted navigation, and one page that uses only Alpine.

Each demo is a few `.astro` files. Each page explains what to look at and links to its source.

The demos run on Cloudflare Workers with D1 for storage. No frontend build step, no JSON API. The server returns HTML, htmx swaps it in.

## A skill for coding agents

Agents know React very well. They know htmx 4 much less, and they reach for `fetch()` and a JSON endpoint out of habit.

So I wrote the rules of the stack as a skill file. It covers the mental model, Astro partials, the htmx 4 attributes and how they differ from htmx 2, when to use htmx and when to use Alpine, and the mistakes I see agents make.

Install it with:

```bash
npx skills add flaviocopes/ahastack.dev@aha-stack
```

Or read it at [ahastack.dev/skill.md](https://ahastack.dev/skill.md).

There's also an [llms.txt](https://ahastack.dev/llms.txt) at the site root, so an agent that browses the site finds the skill on its own.

## Same look everywhere

The docs and the demos now share the same style. Roboto Mono, yellow, pink and black, hard shadows.

If you tried the AHA stack in 2024 and moved on, the [What's changed](https://ahastack.dev/aha/6-whats-changed/) page is the place to start.