Overdue payment reminder email with Gemini in Gmail

An overdue payment reminder has to be clear enough to act on and mild enough to keep the client. Gemini in Gmail drafts one inside the thread in about ten minutes, and the trick is telling it which reminder this is. A first reminder to a long-time partner and a third reminder to a new client with the same debt are different letters, and the model defaults to a tone somewhere in between unless you set it.

Three letters, three tones

Most invoice follow-up has three stages. The first reminder is friendly and assumes a mistake: the invoice got lost, the payment is in progress. The second is businesslike and mentions late fees if the contract has them. The third warns of the next step, such as a formal claim. Decide which one you are writing before you open the panel. Sending the third letter first damages a relationship that one friendly nudge would have kept.

Facts for the prompt

Write down the invoice number, date and amount, the payment term under the contract and how many days overdue the payment is. Note whether the contract has a late fee and at what rate, and how you would describe the relationship. In the prompt, the client, invoice number and amount stay as placeholders; you fill them in the draft yourself.

Role: you are an accountant who reminds clients about payment politely and clearly. Context: client [Client], invoice [No.] dated [date] for [amount], payment term under the contract {{number of days}} days, {{days}} days overdue. This is the {{first, second or third}} reminder. Late fee under the contract: {{yes or no, rate}}. Our relationship with the client: {{long-time partner, new client}}. Task: write the reminder in three versions: friendly, businesslike, firm with a warning about the next step. Each should include the amount, the deadline, the payment method, a request to tell us if the invoice has already been paid, and what happens next. Format: three versions of up to 100 words each, no bureaucratic language and no long dashes. Suggest a subject line for each version separately.

Asking for three versions even when you know the stage is useful: you pick the one closest to your voice and adjust a line or two.

Watch the thread

Gemini in Gmail builds drafts from the whole thread. If the thread contains internal messages, for example a colleague writing "this client always pays late, be firm", the draft may echo that. Before sending, check that nothing from internal discussion leaks into the text. Also check any deadline or amount the model states: it readily promises dates on your behalf, and a reminder that offers "an extra two weeks" you never agreed to becomes the new deadline in the client's mind.

What to do

1. Note the invoice date, amount, contractual payment term and days overdue.
2. Decide whether this is the first, second or third reminder.
3. Open the Gemini panel in the thread and paste the prompt with placeholders for client, invoice and amount.
4. Pick the version that fits and replace the placeholders with real details.
5. Attach a copy of the invoice and check that no internal discussion appears in the text.
6. Send the email and put the date of the next step in your calendar.

The finished reminder

It states the amount, the deadline, the payment method and what happens next; its tone matches the reminder number; and the next step is already in your calendar. The calendar entry is the part people skip, and without it the second reminder goes out a month late.

Plans and privacy

Gemini in Gmail is included in Google AI Pro at 19.99 USD per month for a personal account and in Workspace Business Standard at 14 USD per user with annual billing, where company email stays out of model training. In a personal account, email with client personal data passes through Google without a corporate data processing agreement, so a company mailbox is the better home. See Gemini in Gmail pricing, the accountant's version of this reminder, and Gemini in Gmail vs ChatGPT.