Write a good first prompt

Think of your first message as the start of a conversation. WebDIY reads it, asks about anything it still needs to know and then starts building. The clearer you are up front, the fewer questions it'll ask, and the closer its first version will be to what you pictured.

What to put in your first message

Write it the way you'd explain the idea to the person who's going to build it. A sentence or two on each of these is plenty:

• Who it's for. "Members of my yoga studio", "my team of six", "people who find my pottery on Instagram".
• What people do in it. The two or three main things, like booking a class, browsing products or logging a loan.
• What it keeps. Bookings, orders, sign-ups or notes. When your app needs to remember things, WebDIY offers it a database.
• Who signs in. Say whether people need an account, and what each person can see.
• How it looks. A mood, colors and any fonts you have in mind. A screenshot of a design you like says more than a description.
• What you already have. The name, real text, prices and a logo. Attach any files you have.

There's no need to fit everything into one message. Start with the heart of the idea and add features in later messages.

A few good first messages

Each of these makes a good first message. The businesses are only examples.

A booking page:

A booking page for The Zen Club, my yoga studio. Visitors see this week's classes, pick one and leave their name and email. I need a page where I can see who booked each class. Calm greens and lots of white space, and it should work well on phones.

A catalog for a small shop:

A website for Ember & Slip, a pottery studio. A home page with our story, a gallery of about 20 pieces with photos and prices, and an inquiry form for each piece. Save the inquiries so I can read them. Earthy colors. I've attached our logo and three photos.

A tool for a team:

A tracker for our office equipment. Six of us sign in. We log who borrowed what and when it's due back, and the home page lists anything overdue. Plain and fast, no decoration.

Now compare them with "Make me a website for my bakery". WebDIY can work with that too, but it'll have to ask you about everything first.

What happens once you send it?

WebDIY replies before it builds anything. It asks about the parts it can't work out from your message, and if it needs several answers, it may show a short form in the chat. Fill in the form or type a reply, whichever is easier.

Once it has what it needs, WebDIY builds the first version. You can follow each stage in the chat while the Preview shows your app running. After that, WebDIY checks its own work, taking screenshots of the preview and clicking through your app, with a checklist in the chat.

Each reply shows the credits its message used. A first build does more work than a small change, so it uses more credits. See How credits work.

Add pictures and files

You can attach files to any message from the message box: images, PDFs, plain text and Markdown files. A message can carry up to 10 files, each up to 10 MB.

• A sketch or a screenshot shows the layout you want.
• A logo or a photo can go straight into your app. Ask WebDIY to use it.
• A menu, price list or brief as a PDF or text file saves you typing it all out.

Messages have a length limit, so if a long text won't send, attach it as a file instead.

Keep keys out of the chat

If your app uses a service like Stripe or Resend, don't paste its key into the chat. Add the key in Keys & secrets instead, then tell WebDIY its name. Your app reads each key by its name, so the value never needs to be in a message. See Keys & secrets.

Which model should you use?

The message box shows which AI model your message will use. Your plan's default is a good place to start: DeepSeek V4.1 Flash on Free, and Claude Sonnet 5.5 on Pro and Max. Select the model to pick a different one, or to set how long it thinks (Low, Medium, High or Maximum). More thinking suits harder changes, and it uses more credits.

After the first version

Ask for changes the same way, one or two at a time. Name the page, then say what you see and what you'd like instead: "On the bookings page, the date shows as a number. Show it as Tuesday, March 4."

You can type your next message while WebDIY is still working. It waits as a card above the message box and runs when the current step ends. Teammates wait until your message has finished.

If something looks wrong, describe it in the chat or attach a screenshot. WebDIY can read your app's logs and check the preview for itself.