Graduation Project: Build a Schengen Travel Day Counter

The app and the problem it solves

A traveller planning several European trips can lose track of how earlier visits affect a later itinerary. A day counter is a useful graduation project because its core can be checked independently: enter travel intervals, calculate a rolling window, and show exactly which days were counted.

Call the app StayWindow. Its first release covers the ordinary Schengen short-stay 90/180 calculation for users to whom that rule applies. It should make the calendar understandable, while keeping visa validity, permitted entries and other conditions visible as separate checks. A numerical result alone is not permission to travel.

The first user journey

1. The traveller adds previous entry and exit dates, followed by a proposed trip, without uploading a passport or storing its number.
2. The app validates the dates, combines overlapping intervals and shows a calendar of distinct days spent in the covered area.
3. For each proposed day, it counts presence within that day and the previous 179 days, highlighting the first day that exceeds the model limit.
4. The traveller changes the itinerary, saves the alternative and compares the result with the European Commission’s official calculator.

The logic that makes the project distinct

Represent visits as inclusive calendar-date intervals. Count entry and exit days, and count a date only once when intervals overlap. Moving between Schengen countries does not restart the ordinary short-stay allowance. Use date-only arithmetic so daylight-saving transitions do not create accidental fractions of a day.

The European Commission describes a maximum of 90 days in any 180-day period for the usual short-stay case. Keep this scope explicit. A visa may authorise fewer days, and residence permits, long-stay visas and other circumstances require separate treatment. Do not interpret a remaining-day number as a border-entry decision.

For each proposed date d:
used(d) = distinct presence dates within [d − 179 days, d]
Flag the first proposed date where used(d) > 90.

Data, interface and backend

Ask for a full-stack application: a phone-friendly frontend, backend logic, a database for persistent work, authentication for the personal workspace and payments for the defined offer. Start with private user workspaces and a small, inspectable dataset. These records give the model a concrete starting point:

With Gammal Tech services, personal app data belongs to the user’s workspace. Signing in does not disclose their Gammal Tech account email, phone number or identity to your app. If a later version shares records between people, specify the sharing model and permissions explicitly in the build brief.

A specific paid offer

A small SaaS could offer one calendar freely and charge for saved alternatives, comparison reports and printable travel history. The purchase buys planning features. Keep the underlying rule explanation accessible, and avoid selling a claim that the app can grant travel permission or override a visa condition.

Define the deliverable, price and currency before checkout. Confirm payment with the provider and associate the entitlement with the correct order; a success screen alone is insufficient. Complete the required account and payment setup before real use, and review the applicable operating costs and payment terms.

Refine the idea with [mode: idea]

1. Open the conversation. Open the Gammal Tech WhatsApp conversation with +201033998844. Open the link first, then continue inside WhatsApp.

2. Start Idea mode. Copy the following command into a message by itself and press Send. The square brackets [ ] are required; keep the colon and space too.

[mode: idea]

3. Wait for the mode-change confirmation, then send the brief. Send the following text as a new message, adapting it to your team. Answer the assistant’s questions about the audience, first version and paid value until the idea is approved.

Build the project with [mode: build]

4. Move to Build after the idea is approved. In the same WhatsApp conversation, send the following command by itself, including the square brackets, then press Send.

[mode: build]

5. Wait for the mode-change confirmation, then send the requirements. Use the following message as a starting brief. Agree the scope of the frontend, backend, persistent data, login and payments. Ask about access, setup and fees, and approve the scope and cost before work begins. Simple versions can be prepared in minutes once prerequisites are ready; timing depends on the project scope.

The buttons prepare the command in WhatsApp. Press Send to start the conversation.

6. Review the result and leave the mode when you finish. Open the project link and try the user journey and test cases described in this article. For a correction, name the page and the result you expect. To return to the normal assistant, send the following command by itself, including both square brackets:

[exit]

What to demonstrate at graduation

• An entry and exit on the same date must count as one day, and two overlapping visits must not count a shared date twice.
• A presence date at d minus 179 is included; a date at d minus 180 is excluded. Check both sides of this boundary.
• Compare representative examples with the official calculator and record any scope difference before relying on the result.

For the dissertation, show the counted dates beside each result and explain why a fixed six-month bucket is different from a rolling window. Your strongest evidence is a small set of independently checked edge cases. Expand to other travel rules only as separate, clearly defined models.

Demonstrate the interface, the decision logic and saved work after login. Explain your own understanding, assumptions and evaluation, following your university’s rules on AI assistance. A classroom demonstration can use clearly labelled sample payment states without making a charge. Those samples are not a Gammal Tech gateway test mode; gateway transactions involve real money.

Can this replace the official calculator or a visa decision?

Use it as a transparent planning aid and cross-check it. Visa conditions and the competent authorities remain decisive for the actual trip.

Sources and next steps

• European Commission: short-stay calculator
• Gammal Tech: build a website with AI
• Gammal Tech: backend, login and payment reference

Recheck sources and service terms when implementing. Fictional data and prices in this article illustrate the project, rather than current offers.