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A weekend-built flashcard app for one obscure professional certification exam: $31K revenue in 8 months on $140 of total costs
$31,000 total in 8 months · ~$60K ARR run rate · 4,100 downloads · 700 subscriptions started · $140 total lifetime cost
Eighteen apps shipped in eight months, one of them worked. "Shoot wide and hope to hit something" — and the one that hit was a flashcard app for a tree certification test, built in a single weekend with zero marketing for the first three months.
Fewer bars = easier, cheaper, or faster for an AI-assisted solo builder. Editorial judgments based on the case details.
Herman Palmgren has been writing Flutter apps since 2019 and, by his own count, released 18 apps in the first eight months of 2025. He is unusually honest about the distribution of outcomes: "a lot of them have made no money, and around just one has made this amount of money. The other ones have made, you know, $1,000 here, $2,000 here." He has public videos on the same channel announcing $148 from his first app in half a year and $600 from his second in its first six months. The winner was the second app he shipped in 2025, launched on January 21st. It's a flashcard and study app for what he describes as "a very specific and niche tree related test in the US and Canada primarily" — an arborist certification exam. He built the first version in a weekend and has since shipped roughly 20 updates, adding an AI feature and mock exams, and experimenting with the paywall to lift monetisation. The first three months were quiet — around $400-500 per month and 500-600 downloads total, with zero marketing of any kind. People were finding it by searching the App Store, which he took as the demand signal. April is when it broke. He started what he calls guerrilla marketing and added $2,000 of net new MRR in that single month. From there, word of mouth and app store optimisation took over. At the time of recording the app sits "just north of $5,000 MRR" having generated $31,000 since launch, with August alone bringing in almost $7,000 — an ARR run rate of about $60,000. Total lifetime cost to run it: roughly $140.
The first customers arrived without being asked. Herman launched on 21 January with no marketing of any kind, got a handful of downloads immediately, and read the signal correctly: people were typing this certification into App Store search and finding him there.
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Data credibility: Founder's own YouTube channel, self-reported, narrated over dashboards but with no clear screen-share of a revenue dashboard described in the transcript. The specific figures — 4,100 downloads, 700 subscriptions started, $5K+ MRR, $31,000 lifetime revenue, ~$60K ARR run rate, ~$140 total costs, $2,000 of MRR added in April, 70/20/10 US/Canada/other geo split — are all his own numbers. The $140 cost figure explicitly covers only RevenueCat fees and ~$40 of Google Gemini spend and does not account for Apple's and Google's platform commission on the $31,000 of gross revenue. The exam is never named in the video (described only as 'a very specific and niche tree related test'), so the app itself is not independently verifiable. He also promotes his own paid Flutter boilerplate product, mobilelaunch.io, in the same video, which is a commercial interest in this story being compelling. His earlier public numbers ($148 from a first app, $600 from a second) support rather than undermine the credibility of the reporting.
The money is subscription revenue billed through RevenueCat, and the paywall design is the reason there is any.
He seeded the loop by hand for one month and it has been turning on its own since.
Two silences run through this story. The short one is the first three months: 500-600 downloads, $400-500 a month, no marketing and no curve to point at.
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