Restaurant customer database: what to collect and how to stay legal
Your server knows Carla comes in every Thursday afternoon. If he leaves, that knowledge leaves with him. Here’s how to build a guest list that’s useful and legal.
You know Carla comes in every Thursday for merienda and orders a ham-and-cheese toastie with a smoothie. But if she stops coming, you have no way to tell her that her favorite cake is back. A restaurant customer database turns your server’s memory into something that stays when staff change.
What data to keep (and what to skip)
You don’t need an enterprise CRM. The rule: ask only for what you’ll use.
| Data | What it’s for | Ask for it? |
|---|---|---|
| Name | Greeting and personal touch | Yes |
| Mobile or WhatsApp | Updates and perks | Yes |
| Birthday (day and month) | Greeting and a gift | Optional |
| Visits and orders | Frequency and favorite dishes | Logged automatically |
| ID number, address, birth year | Almost never needed | No |
Be careful with allergies and health data: the law treats them as sensitive data. Ask when taking the order; don’t store them for marketing.
Your customer database and Argentina’s Law 25,326
Argentina’s Personal Data Protection Law (Ley 25.326) covers even a café’s guest list. In practice:
- Free, express and informed consent: an unticked checkbox that says what you’ll do with the data.
- A clear purpose: “We’ll message you on WhatsApp with perks and your birthday gift.” For anything else, ask again.
- Access, correction and deletion: guests can ask to see, fix or erase their data; give them an easy way to do it.
- Security: no spreadsheets shared by open link, no lists on servers’ personal phones.
- Registration: the law provides for registering databases with the National Database Registry run by the AAIP.
How to grow the database without being pushy
- 01
Scans the menu
The guest orders from the table.
- 02
Sees a perk
“Join and get a free stamp.”
- 03
Gives consent
Name, phone and a consent checkbox.
- 04
Gets value
A stamp card and a birthday surprise.
Nobody hands over their number “to get news”: they do it for something concrete.
Customer segments that actually matter
- New (1 visit): aim for a second visit within 30 days.
- Regulars (3+ visits in 2 months): more recognition, not more discounts.
- Lapsed (45+ days away): see how to win back lost guests.
- Birthdays this month: ideas in birthday promotions.
Example: a café in Palermo has 600 guests in its database, 90 of them lapsed. If a message offering a free medialuna brings back 15, at an ARS 9,000 check that’s ARS 135,000 in sales for the cost of 15 pastries.
Can I use WhatsApp numbers from reservations to send promotions?
Only if the guest agreed to receive them. A number given to confirm a booking isn’t marketing consent.
Is an Excel spreadsheet enough?
To start, a protected spreadsheet works. Once you have a few hundred guests, a system that logs visits automatically and handles opt-outs is worth it.
- #guest data
- #retention
- #analytics
- #loyalty