Building A Retirement Countdown With AI: A Five-Day Account

🔍 Read the full analysis: Building A Retirement Countdown With AI: A Five-Day Account on ThorstenMeyerAI.com

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Developer Thorsten Meyer says he built and published Altersteilzeit, a web app for counting down the working days in a German partial-retirement arrangement, with help from an AI coding agent over five days, from September 28 to October 2, 2026. His October 13 account describes a project that grew from a request for a one-minute animated film into a countdown tool with a film, games and multilingual narration; Meyer says he directed the work and approved releases.

The app is designed for Germany’s Altersteilzeit block model, in which a person works a regular schedule during an active phase and then spends an equally long period away from work. Meyer says users enter the start date of either phase and choose a model from 1:1 to 5:5. The app calculates the other date and counts weekdays, subtracting public holidays for the selected German federal state and any leave entered by the user.

Meyer describes three main ways to use that shared date information: a daily countdown with milestones and a saying of the day; a short film depicting the active and passive phases; and a game collection that turns years of the active phase into levels. The account also lists features including calendar exports, a printable countdown calendar, a bridge-day finder, badges and a team countdown. Meyer’s description gives different counts for the games: it refers to nineteen 3D games in the completed app, but later says the game has fifteen modes.

The project was credited to the agent in each of 24 commits, according to Meyer. He says the agent wrote code, tested features, documented work and handled deployment, while he set the concept and tone, made product decisions and approved releases. The account reports roughly 18,000 lines of JavaScript and Python, 15 test scripts and 1,224 voice clips; these are figures supplied by Meyer, not independently verified measurements.

What the Five-Day Build Shows

The account offers a concrete example of how an AI coding agent can contribute to a small software project when a human developer gives it a defined goal and reviews the output. The result described by Meyer goes beyond a countdown: it combines date calculations, browser-based games, narration and localization in one public-facing app. That makes the project relevant to developers weighing whether such agents can take on work across coding, testing and production tasks.

Meyer’s description also draws a boundary around the agent’s role. He says he remained responsible for decisions about the app’s concept, humour, voices, dialects and publication. The account is therefore evidence of one developer’s workflow and reported output, not a controlled comparison of productivity or proof that similar projects will take the same time. It does not establish how much time the agent saved or how the finished app performs for users.

Privacy is another stated product choice. Meyer says the app has no accounts, cookies or tracking and performs calculations in the browser. Shared dates are placed after the hash mark in a web address, which browsers do not send to servers in ordinary HTTP requests. That design may matter to users entering personal work dates, though the article does not include an independent privacy or security review.

From Film Request to Public App

Meyer says the project began on Monday, September 28, with a request for a short animated film counting down the working days in an Altersteilzeit arrangement. The first day’s work expanded to include leave and working-day calculations, personal dates and early game prototypes. By that evening, he says, the project was online with legal pages.

Over the following days, the account describes the addition of seven interface languages, a daily countdown, more games, badges, a bridge-day finder, sound effects and a narrator. On day five, Meyer says he approved the work and added five German dialects as full language options, with voices. His article also says that the finished app offers twelve languages in total, reflecting its distinction between languages and dialect options.

The calendar is central to the game design. Meyer says game elements correspond to real periods, such as months, weeks, working days and quarters, while entered leave can affect gameplay. He also says the game titles were chosen to avoid other companies’ trademarks. These details reflect the developer’s account of the design, rather than an external evaluation of the app.

“It started as a one-minute film.”

— Thorsten Meyer, describing the project’s starting point

What the Account Does Not Verify

The project details come from Meyer’s first-person account. The material does not include independent testing, user figures, a third-party code review or a comparison with a similar project built without an AI agent. It is not clear how many people have used the app, whether all listed features are available in the current public release, or whether the reported build and production totals have been checked independently.

There is also a difference in the game counts presented: the article describes nineteen 3D games in one passage and fifteen playable modes in another. Those figures may refer to different ways of counting games and modes, but Meyer’s account does not explain the distinction. The source does not provide a full breakdown of the twelve languages, either, beyond noting that five German dialects were added.

The privacy statements are also descriptions of the design, not the findings of an outside audit. The account does not provide details about hosting, security testing, or how the app’s legal pages address data handling. No independent technical assessment or user feedback is included.

The App’s Next Public Test

Meyer’s account describes the app as publicly available by October 2, but it does not give a roadmap, a planned update date or a next development milestone. No subsequent release, user response or independent review is specified in the source material.

The next useful developments for readers would be evidence about how the app works in practice: whether its working-day calculations match users’ selected state holidays and leave, how well it runs across devices, and whether its privacy claims hold up under technical review. Until such information is available, the five-day timeline and project totals should be understood as Meyer’s report of his own build.

Key Questions

What is the Altersteilzeit countdown app?

It is a web app Meyer says he built for people using Germany’s Altersteilzeit block model. Users enter a phase start date and model, and the app calculates a countdown in working days.

How long did the project take?

Meyer says work ran from September 28 to October 2, 2026, with the app online by the end of the first day and further features added over the next four days.

What did the AI coding agent do?

According to Meyer, the agent handled coding, tests, documentation and deployment, as well as work on games, translations and voice clips. Meyer says he supplied direction, made decisions and approved releases.

Does the article independently verify the app’s features or development totals?

No. The feature list, commit count and production figures are reported by Meyer. The source material does not include independent testing, a code review or user statistics.

What is still unclear about the app?

The source does not report user numbers, independent privacy testing or a future update schedule. It also gives two counts for the game collection—nineteen games and fifteen modes—without explaining how the counts differ.

Source: ThorstenMeyerAI.com