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Start From a Template: A Written First Prompt for Your App

Mythex templates give you a starter prompt tuned for a kind of site or app. Pick one, press Use template, and the agent builds a first version you then refine.

Mythex Team · 2026-09-29 · 4 min read

Mythex has a library of templates at mythex.ai/templates. Each one describes a kind of site or app — a waitlist landing page, a barbershop booking site, a sales CRM — and comes with a starter prompt written for it. Press Use template and Mythex creates a new project with that prompt ready to run, so the agent builds a first version you can then refine in chat.

What a template is

A Mythex template is a starter prompt, not a starter project. That difference matters, so it's worth being precise:

Templates areTemplates are not
Starter pages with a carefully written first promptPre-built projects you remix or clone in one click
A new AI build from that promptGuaranteed pixel-perfect copies of a fixed design
Free to open — same credits and rules as any new projectA separate product from the normal dashboard composer

When you use one, the agent builds your app fresh from the prompt. You get your own project, built for you, not a copy of someone else's.

Why prompts, not projects

The hardest part of starting is often the first message. You know you want "a booking site for my barbershop", but not which pages it needs, what the booking flow should look like, or which details to mention. A good opening prompt covers those things, and it's easy to leave half of them out when you write one from scratch.

A template prompt is written for its use case, so the first version starts closer to what that kind of site needs. Because it's a prompt rather than a fixed codebase, the result isn't locked to someone else's design choices. Everything that happens next is the same as any project: you steer it in chat.

How to use a template

  1. Open Templates on the Mythex site. It's also linked from the home page and the main navigation.
  2. Find one. Search by keyword, or use Filters to narrow by category and subcategory. On a phone, Filters opens as a sheet from the bottom. If nothing fits, you'll see No templates match.
  3. Click Use template.
  4. Sign up or log in if you aren't already. Mythex creates a new project with the template's prompt filled in.
  5. Watch the agent build the first version, then refine it in chat.

After you start

Treat the first result as a draft. From here it's a normal project:

  • Change the copy, layout and features by asking in chat.
  • Switch between Preview and Code as you would anywhere else.
  • Publish when you're ready.

Small, specific follow-ups work better than asking for a rebuild. If a change goes wrong, roll it back with a checkpoint.

Which tech your app is built with

Templates set the product brief, not the files. Mythex still chooses the technology from the prompt. If nothing says otherwise, it starts from Vite + React + TypeScript + Tailwind — a common modern setup for web apps — with a live preview ready while you chat.

Mythex doesn't ask you to pick a framework on a settings screen. It infers the setup from what you write. So if you want something specific, say it — in your own first message, or in chat as soon as a template project starts:

  • "Use Next.js"
  • "Plain static HTML landing page"
  • "Python backend with a simple web front"
  • "C# API" or "Java backend"

For backends that need a container, such as C# or Java services, Mythex writes the app plus a Dockerfile (a recipe for building a container image) and records how to run and publish it. The preview runs in your private sandbox, and Publish builds the image and deploys it through the same publish flow as any other app. There's no hosting for you to set up.

You can ask to change stack later, but naming a preference early saves credits.

Limits

  • There's no template gallery inside the workspace yet. Templates live on the public site; Use template sends you into the normal create-project flow with the prompt filled in.
  • Results vary. Because each template is a prompt the agent builds from, two projects from the same template won't necessarily look the same, and neither is a copy of a fixed design.
  • Templates don't lock your stack. They set what to build, not how. Say your stack preference in the prompt if you have one.
  • Building from a template costs the same as building from any other first prompt.

If you'd rather write your own opening prompt, our guide on how to write prompts for AI app builders covers what to include, and how to build a landing page that converts is a good companion to the landing page templates.

The docs have the details: Website & app templates and How the tech is chosen.

Keep reading

  • A Landing Page for Every Kind of Business — Search for a booking system for a dental clinic or a website for a bakery and land on a Mythex page written for that business, with a prompt ready to build it.
  • A Private Workspace and a Live Preview for Every Project — Every Mythex project runs in its own private cloud workspace with a live preview beside the chat. How it works, how to use it, and what to expect.
  • Auto-Reload: Keep Your Published App Running When Credits Run Low — Auto-reload buys Mythex credits when your balance runs low, so a long build or a busy published app does not stop at zero. How to set it up, and its limits.
  • Build Mythex Apps from Claude, Cursor or Codex — Mythex runs a remote MCP server: connect Claude, Cursor or Codex, and they code in your Mythex cloud sandbox with a live preview, database and publishing.
  • Checkpoints: Undo Any Change the Agent Makes — After every successful turn, Mythex saves a checkpoint of your project. Revert to any of them in two clicks, or edit an earlier message and try again.
  • Connect Gmail, Google Sheets and Slack to Your App Builder — Mythex Connectors link Gmail, Google Sheets, Slack, Notion and more to the chat agent, with no API keys in your code. How it works, setup, and limits.

Start building free · Templates · Docs