Guide · 3 minute read · 21 October 2026
What to ask your AI tool before you put your app online
The things that break when an app goes online are mostly the same few, and your AI tool can check for them if you ask. Here are the questions, in the order worth asking. Paste them one at a time and read each answer before moving on.
1. Does it need a server?
“Does this app need a server running all the time, or can it be built into static files? If it needs a server, which parts need it?”
This decides where the app can go online and what it will cost. Our guide on telling the two kinds apart goes further.
2. Where are the keys?
“List every API key and secret this app uses. For each one, tell me whether it ends up in the files the browser downloads, and whether that's safe.”
A private key in the browser can be copied and used on your account. More on which keys are safe.
3. Which settings does it need?
“List every setting this app reads from .env, which ones it needs to start, and what happens if one is missing.”
You'll give these to your host. A missing one is a common cause of a blank page.
4. Is anything pointing at my computer?
“Search the code for localhost and 127.0.0.1 and tell me which of those will break once the app is online.”
An app that calls http://localhost:3000 only works while your own computer is running it.
5. Where does it save data?
“Where does this app save data? Will that still work when it isn't running on my computer, and will every visitor see the same data?”
Data saved in the browser stays on that one visitor's device. Data saved to a file in the project folder can disappear on hosts that reset their files when the app restarts.
6. How do I build it?
“How do I build this for production, and which folder holds the result?”
The answer is usually npm run build and a folder called dist or build. If your host builds for you, you'll still want this to check its settings.
7. Does it work on a phone?
“Check every page at 375 pixels wide and fix anything that runs off the edge or is too small to tap.”
A link sent in a group chat gets opened on phones. You can see the phone view yourself in Chrome: open the developer tools and click the icon of a phone and a tablet.
8. What does a visitor see when something fails?
“What does a visitor see if a request fails or the page hits an error? Replace any blank screen with a short message that says what happened.”
A blank screen looks like the app is gone for good. One sentence saying what happened, and to try again, keeps the visitor.