Fixing your AI app shouldn't cost you money

Where the credits go

On a credit-metered builder, the model's mistakes are your expense. Lovable's documentation gives examples of a build-mode message costing anywhere from 0.50 credits for a small style change to 2.00 credits for a landing page, and says the real number depends on your project. Nothing in the price distinguishes a message that adds a feature from a message that repairs one. When the balance reaches zero, building stops until you top up, at $0.30 a credit on the Pro plan (checked September 2026, docs.lovable.dev).

The loop is familiar to anyone who has used one of these tools. You ask for a booking form. The reply says it is done. You open the preview, fill it in, press the button, and nothing happens. You describe what you saw. The reply says it is fixed. You try again. The second field now clears itself while you type. You describe that. Three messages later the form works, and you have paid for four messages to get one feature.

None of that is unusual. Models make small, ordinary mistakes: a component defined in the wrong place so a text box resets after every letter, a delete that removes the item from the screen but not from storage, an upload that saves a link that expires in an hour. A developer catches them in a minute. An owner catches them when a customer does. A credit model charges either one to say so.

What JustCopy does after every build

The build does not end when the model says “Done”. It ends when the app has been used. After the page is written, JustCopy writes three to five short stories about it, in your words: “Request a booking”, “Add an expense and see it in the list”, “Upload a photo”, “Reload and the entries are still there”. Each one is a few steps a script can perform and one thing that must be true at the end.

Then it performs them, in the preview, while you watch. A cursor appears in your app the way it does when something else is holding the wheel. It glides to the button and presses it. It types into the form one character at a time. It draws a sample photo and drops it into the upload. It reloads the page and checks the words survived. It listens for errors the page throws and for requests that fail. At the end of each story there is a tick or a cross, and the app pane says which story it is on.

A cross is a free fix. The reason the story failed, the step it failed on, any error from the page and the text that was on screen go to the model as a fix turn. That turn is not charged and does not count against your daily builds. The failed stories run again on the repaired page. If something still fails, one more round runs. Two free fix rounds can follow one build, and each round shows on its own card in the chat so you can see what was found and what was done.

Three steps, no charge

1. 1

   It writes the stories

   From the page it just built: "Request a booking", "Add an expense", "Upload a photo". A label in your words, steps a script can perform, and what must be true after.

2. 2

   It uses the app in front of you

   A cursor appears in the preview, glides to the button, presses it, types into the field one character at a time, drops a sample photo into the upload. You watch it happen.

3. 3

   A cross becomes a free fix

   When the text that should appear does not, or the page throws an error, the fix turn runs with the reason attached. Then the failed stories run again. Up to two fix rounds.

One week of it

From our build logs, 13 to 19 September 2026: JustCopy ran 128 first builds and made 199 automatic repairs, and charged owners $0 for the repairs. That is more repairs than builds, which is the honest picture of what a model gets wrong the first time on a real page with a real form. On a credit model, those 199 repairs would have been 199 messages sent by the owner, each after finding the fault, each charged.

The same week saw 128 changes to existing apps. Twelve of those were instant edits with no model involved at all: a word, a price, a color or a section changed on a page the platform had built, done in seconds and free on every plan. Those never touch the daily build count either.

What is free and what a build costs

To be exact about it. A build is one message that asks the model to build or change your app, and each plan has a daily number: 3 a day on Free, 5 on Hobby at $9.99, 10 on Starter at $24.99, 25 on Professional at $49.99 and 50 on Business at $99.99. Those are the only messages that count, and they are a quota, not a balance. Tomorrow there are more.

Fix turns the testing phase asks for are free. Text, color and section changes on a page the platform built are free. Trying another look for the same page is free. None of them reduce the day's builds. So a Free plan owner who asks for a booking site in the morning has spent one build, watched it get tested and repaired at no cost, and still has two builds left for the afternoon.

What it does not do

The stories never sign in, sign up or sign out, because the preview shares your own JustCopy session. Anything a story creates, a record or a file, is tracked and removed when the phase ends, and a reload in the middle of a run does not leave test entries behind. A story that would need a payment, an email, a text or a phone call is listed and skipped with a plain reason, because the test should not send your customers anything. The driver clicks, types, uploads and reloads; it does not yet pick from dropdowns or date pickers, and a story whose button is not on the page is dropped before it runs rather than guessed at.

So it does not catch everything. It catches the ordinary things, the text box that forgets, the delete that does not stick, the upload that does not show, and it catches them before you do, at no cost. What it cannot run, it does not claim to have run.

If your credits ran out today

Two practical notes. First, Lovable's documentation says a published site stays live when the balance hits zero and its pages keep serving, though AI features inside the app stop and apps that depend on the built-in backend can pause (checked September 2026, docs.lovable.dev). Your site is not gone; your ability to change it is, until you pay.

Second, building on JustCopy is free with no card: describe the business in one sentence, the site is on screen in seconds, and the testing runs on it while you watch. Three builds a day, five projects, and every repair on the house. If the tool you were using charged you for its own mistakes, that is the difference worth trying.

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