A Countdown To Retirement, Built In 16 Versions With AI

🔍 Read the full analysis: A Countdown To Retirement, Built In 16 Versions With AI on ThorstenMeyerAI.com

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Developer Thorsten Meyer says he built and published a free web app for people counting down to the end of a German partial-retirement work phase, working with the AI coding agent Claude Opus 5.5 over five days. What began on September 28, 2026, as a request for a one-minute animated film grew into a public site with a daily working-day countdown, a short film, 3D games, calendar tools and multilingual narration; Meyer says he set the direction and approved releases.

Meyer’s account, published on ThorstenMeyerAI.com on October 13, describes a project developed from Monday, September 28, through Friday, October 2. He says it passed through 16 versions during that period and that all 24 commits were co-authored by Claude Opus 5.5. The account presents the app as a collaboration: the agent planned and implemented requested features, while Meyer made product and design decisions, reviewed the results and approved deployment.

The app is designed for Altersteilzeit in the block model, a German partial-retirement arrangement in which a person works their usual schedule during an active phase and is then released from work during a passive phase. Users enter a date for the start of either phase and choose a model, from 1:1 to 5:5. According to Meyer, the app calculates the corresponding dates and remaining working days, accounting for weekdays, public holidays in the user’s German federal state and entered leave.

The published feature list includes a daily countdown and milestone view, a short film depicting the two phases, a 3D game with 19 ways to play, a bridge-day finder, a team countdown, badges and calendar exports. Meyer says the app supports seven languages and five German dialects, with narration and sound effects. The account also describes a privacy-focused design: no accounts, cookies or tracking, with calculations performed in the browser and shared dates placed after the # in a link address.

A Personal Countdown Becomes a Public Tool

The project matters as a concrete example of how a developer used an AI coding agent to turn a narrow personal request into a larger, publicly accessible application. Its scope expanded well beyond animation to include date calculations, multilingual content, browser-based 3D games and deployment. Meyer’s account offers a view of the work involved: describing features, reviewing generated output, testing fixes and making choices the agent did not make for him.

For people approaching partial retirement, the app aims to make a long work-to-retirement timeline easier to follow day by day. The countdown translates a date range into working days and milestones, while the film and games present the same timeline in more playful forms. These are the developer’s stated product goals; the source does not provide user numbers or independent evidence about how many people have adopted the app or whether it changes users’ experience.

The account also highlights a practical division of labor. Meyer says the agent generated code and handled tasks such as translations, audio production and testing, while he retained control of the app’s tone and release decisions. That distinction is relevant to readers evaluating claims about AI-built software: this was not described as a project completed without human involvement, but as rapid development directed and approved by a person.

From Film Request to Countdown App

The initial request, according to Meyer, was made on Monday, September 28: create a short animated film about the working days in a German Altersteilzeit block-model arrangement. The app took shape over the next five days. Meyer describes the first day as a mix of film work, leave and working-day calculations, user-entered dates and early 3D game prototypes. The site was online that evening, he says, and the following days added languages, a daily view, games, badges, a bridge-day finder and narration.

The project’s organizing idea was to map real calendar time into the app’s features. Meyer says game stages correspond to calendar periods: for example, months and weeks structure a maze, while working days become events in other games. The published account describes 19 game modes, although an earlier passage in the same account refers to the game as having fifteen modes. That discrepancy is not resolved in the source.

Meyer says the agent’s work included roughly 18,000 lines of JavaScript and Python, 15 test scripts, text strings in 12 languages, 1,224 voice clips and 17 sound effects. Those figures come from the developer’s account and are not independently verified in the supplied material. Meyer also says he chose the project’s humor and visual direction, selected voices and dialects, and reviewed legal-page details before approving the release.

“The interesting part is not how much an AI agent can build, but what was still left for me to do.”

— Thorsten Meyer, project developer

Adoption and Technical Claims Unverified

The source is a first-person account by the project’s developer, not an independent technical review. It does not include external testing of the working-day calculations, accessibility, security or privacy implementation, nor does it report user numbers, feedback or performance across devices. Readers therefore cannot tell from the account alone how the app performs in routine use or whether its calculations have been independently checked.

Some details also need clarification. Meyer’s article refers to a game with 19 ways to play, but elsewhere says the game has fifteen modes. It reports seven languages and five German dialects, while also describing 1,224 voice clips at 102 per language across 12 languages. The source does not explain how those language counts relate to one another. It also gives no information about the agent’s access, the amount of manual code editing, or how much time Meyer spent reviewing and correcting outputs.

App Use and Verification Remain Open

Meyer’s October 13 account describes the app as publicly available, but does not announce a future release date, development roadmap or planned feature. The immediate next step for prospective users is to consult the site and check whether its dates, language options and privacy practices meet their needs. The source does not say whether the project will receive further updates or how users can report errors.

For a clearer picture of the project’s reach and reliability, future reporting would need information from users and independent checks of the date calculations, browser behavior and privacy claims. Meyer’s account establishes what he says was built and how he describes the collaboration; adoption, independent verification and any further development remain unreported.

Key Questions

What does the Altersteilzeit app do?

According to Meyer, it calculates working days remaining in a German block-model partial-retirement plan and offers a daily countdown, milestones, a short film, games and calendar tools.

How long did development take?

Meyer says work ran from September 28 to October 2, 2026, with the project passing through 16 versions. He reports 24 commits co-authored by Claude Opus 5.5.

Did the AI agent build the app on its own?

No. Meyer describes directing the work, choosing the concept and tone, reviewing features and approving releases. The agent handled much of the implementation and production work, according to his account.

What information does the app use to calculate working days?

Meyer says users enter a phase start date and choose a model. The app then accounts for weekdays, public holidays in the selected German federal state and entered leave.

Have the app’s privacy and calculation claims been independently checked?

The supplied account does not describe an independent audit or validation. Claims about browser-only calculations, no tracking and date accuracy are the developer’s descriptions.

Source: ThorstenMeyerAI.com