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How to make an invoice with ChatGPT (and what happens to your data)

Monkee · September 13, 2026

A lot of freelancers now make invoices by asking ChatGPT. It works, sort of. But there is a smarter way to use it: do not ask the AI to make the invoice. Ask it to build a prefill link. You open the link, review the invoice, and download the PDF yourself. It takes the same thirty seconds, and your client data never touches another server. Here is the exact prompt, plus an honest account of what happens to your data at each step.

The trick in three steps

1. Paste the prompt below into ChatGPT, Claude, or any assistant, with your invoice details filled in.
2. Open the link it gives back. The invoice opens pre-filled in your browser. Check it the way you would check anything a client will see.
3. Download the PDF. Done. If the link looks wrong, run it through the link checker first.

The copy-paste prompt

Build me a MonkeeTools invoice prefill link using this exact format:

https://monkeetools.pages.dev/#v=1&from=MY BUSINESS&to=CLIENT NAME&invoice=INV-001&currency=USD&date=2026-09-13&due=2026-09-27&item=Description|1|500

Rules:
- Put everything after the # (the URL fragment). URL-encode spaces.
- item=DESCRIPTION|QTY|RATE, repeatable up to 12 times.
- currency is a 3-letter code: USD, EUR, GBP, CAD, AUD, JPY.

My invoice details:
[from: your business name]
[to: client name]
[invoice: number, e.g. 2026-006]
[line items with quantities and rates]
[due date]

Reply with ONLY the finished link, nothing else.

Swap the bracketed lines for your real details and send it. The AI hands back a link like the example at the bottom of this post. One click opens a complete invoice draft.

What happens to your data, honestly

Most guides skip this part. Here it is, step by step:

• Step 1, the chat. Whatever you paste into ChatGPT is visible to OpenAI under their data policy. Training on conversations is on by default; you can turn it off in Settings, then Data Controls, then "Improve the model for everyone." Claude is the same story: the "Help improve Claude" toggle has been on by default since September 2025, opt out in Settings, then Privacy. If the client details are sensitive, use a temporary chat (never used for training) or redact names before pasting.
• Step 2, the link. The invoice details live in the URL fragment, the part after the #. Browsers never send fragments to servers and never include them in referrers. The AI never uploads anything; it just writes text.
• Step 3, the invoice tool. MonkeeTools builds the invoice from the fragment entirely in your browser tab. Nothing is uploaded, no account exists to attach it to. You can verify this yourself: open the network tab, load a prefill link, and watch zero invoice data leave the page. Our privacy page documents exactly how to check.

The honest summary: the chat step is the one place your data is exposed, and that is true of any AI-assisted workflow. The prefill-link trick keeps everything after that point local, which asking the AI to "just make the PDF" cannot do.

Why not just ask ChatGPT for the invoice directly?

• No numbering continuity. Every chat starts from zero. Nobody remembers that your last invoice was 2026-005, so numbers drift, duplicate, or restart.
• No history. Next month you will retype the same client, the same address, the same line items. A tool that remembers you does it in one click.
• Inconsistent formatting. Model output varies run to run. A real invoice template looks the same every time, which is what makes clients take your payment terms seriously.
• It lives in your chat history. Your client list, your rates, your revenue, sitting in a chat log on someone else's server indefinitely.

See it done: a working example

This is the kind of link the prompt produces. It loads a complete invoice into the generator, free, no signup, editable the moment it opens:

Open the AI-built example invoice

Check it, change the names, download the PDF. And if an AI ever hands you a suspicious link, paste it into the link checker before opening it.

Use the AI for the typing. Use the tool for the invoice. Keep your data out of everywhere else.

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