My Five-Day Journey Building A Retirement Countdown With AI

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

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Thorsten Meyer says he built and published a free web app for people nearing German partial retirement in five days, working with the Claude Opus 5.5 coding agent. What began on Sept. 28, 2026, as a request for a one-minute animated film had become a countdown tool with a narrated film, games and other features by Oct. 2, according to Meyer’s account published on ThorstenMeyerAI.com.

The app, called Altersteilzeit, is designed for the “block model” of partial retirement: a period of regular work followed by an equally long period away from work. Users enter a date and choose a model from 1:1 to 5:5. The site calculates the corresponding phase dates and remaining working days, taking weekdays, state public holidays and entered leave into account, Meyer writes.

Meyer describes three main experiences built around those dates: a daily countdown with milestones and a progress display, a short narrated film about the user’s two phases, and a game collection that maps time in the working phase to levels. Other listed features include calendar exports, a bridge-day finder, badges, a team countdown and legal pages. The article describes the collection as nineteen 3D games, while its day-by-day account says games were added in stages.

Meyer says all 24 commits were co-authored by the coding agent. He describes the agent as writing and testing code, documenting work, producing translations and voice clips, and helping deploy the site. Meyer says he gave instructions, chose the app’s tone and features, reviewed the output and approved the release. The figures and description are reported by Meyer; the source provides no independent audit of the code or development process.

A Countdown Built Around Real Workdays

The project illustrates how a coding agent can be used across a small product’s development, not just to generate a code snippet. In Meyer’s description, the same collaboration covered engineering, content production and deployment, including interface text, narration and testing. That makes the account relevant to people evaluating AI coding tools for complete, public-facing projects.

The app also addresses a specific planning need: a countdown based on a person’s work schedule, holidays and leave, rather than a simple calendar-day timer. For prospective users, the practical value depends on whether those calculations match their circumstances and whether the app’s features work reliably. Meyer describes the intended functions, but does not provide user numbers, independent testing results or evidence of uptake.

The account also shows that the developer’s role did not disappear. Decisions about humor, imagery, language variants, voices and legal-page contact details remained with Meyer, who says he reviewed the work and signed off. The report is a firsthand account of one project, not a controlled comparison of AI-assisted and conventional development.

From Film Request to Public App

Meyer says the work began on Monday, Sept. 28, 2026, with a request for a short animated film counting down working days in a German Altersteilzeit arrangement. In the block model, a person first works as usual for a set period and then enters a period away from work of the same length; a 4:4 arrangement, for example, means four years in each phase.

According to his timeline, the first day brought the film concept, date calculations and two game prototypes. The daily countdown and additional games followed on day two. Meyer says day three brought more games, badges and a bridge-day finder, along with a fix for an iPhone scrolling problem. Narration and sound effects followed on day four; he approved the work and added German dialect versions on day five.

Meyer says the finished site includes seven languages and five German dialects. He also says privacy was a design goal: the app has no accounts, cookies or tracking, and calculations run in the browser. Shared dates are placed after the “#” in a web address, which browsers do not send to a server in a normal web request, according to his explanation.

“I gave directions, made decisions and approved releases.”

— Thorsten Meyer, describing his role in the project

Independent Testing Has Not Been Provided

Meyer’s article is a first-person account and does not include an independent assessment of the working-day calculations, accessibility, security or reliability of the public app. It also gives no user totals, feedback data or evidence that the stated privacy behavior has been externally verified.

Some details in the account are difficult to reconcile from the text alone. It describes nineteen games, but also refers to fifteen modes in one passage; it reports twelve languages for the narrator while elsewhere listing seven languages and five German dialects. The source does not explain how those counts relate. It also does not quantify the time saved compared with building the same product without an AI agent.

Public Use Will Test the App

The app was online by Oct. 2, according to Meyer, so the next practical measure is whether people can use it as intended: enter their dates, check the working-day count and rely on the calendar and game features. Meyer’s account does not announce a later release date, user study or outside review.

Readers considering the countdown for their own retirement planning should check that the selected model, regional public holidays and leave entries reflect their circumstances. The source describes the app’s calculations and privacy approach but does not document independent verification. Further reporting would need to establish how the site performs in use and whether its published details are confirmed by testing.

Key Questions

What did Thorsten Meyer build?

Meyer says he published Altersteilzeit, a free web app that counts down working days in a German partial-retirement block model and includes a film, games and planning features.

How long did the project take?

Meyer dates the work from Sept. 28 to Oct. 2, 2026, a five-day period. That timeline comes from his own account.

What did the AI coding agent do?

Meyer says the Claude Opus 5.5 agent helped write and test code, produce translations and audio, document work and deploy the site. He says he supplied direction, made product decisions and approved releases.

Does the app track users?

Meyer says the app has no accounts, cookies or tracking and runs calculations in the browser. The source does not cite an independent privacy audit.

Has the app’s accuracy been independently confirmed?

The source provides Meyer’s description of how the app calculates working days, but does not report independent testing of its holiday, leave or date calculations.

Source: ThorstenMeyerAI.com