Danielle Simpson taught English online to students in China. After a shift that could run ten hours, she still had to write personalised feedback for every student, which took another two hours or more. Her partner, a software engineer in Germany named Arvid Kahl, built her a tool to do it faster. That tool became FeedbackPanda. It launched in 2017 at $5 a month, reached $20,000 a month in recurring revenue within nine months, and was sold to SureSwift Capital in June 2019 for an undisclosed seven-figure sum, at roughly $55,000 in monthly recurring revenue with about 5,000 customers.
Two years, two people, no employees, no funding, no advertising.
The idea was sitting at the kitchen table
Most founder stories start with a market. This one starts with watching someone you live with do unpaid work every night. In an interview on the SaaS Club podcast, Kahl describes the problem in the plainest terms available: the feedback was mandatory, the teachers were not paid for it, and it ate the hours after an already long day.
The product did one job. It let a teacher assemble student feedback from reusable templates instead of writing each one from scratch, and a browser extension dropped it directly into the platforms the teachers already used. Kahl says he built the first version in three to four weeks, moonlighting around his day job, in Elixir and Phoenix, with Stripe wired in from day one.
That last detail matters more than the stack. Payment was in the product before the first customer was. Builtplain has argued that the most reliable place to find a product is inside complaints people are already making out loud. FeedbackPanda is the domestic version of that: the complaint was audible from the next room.
One Facebook comment, one hundred signups
The launch was not a launch. Danielle left a comment in a Facebook group for online teachers saying, in Kahl's retelling, "I use Feedback Panda." About a hundred people signed up that day.
Those groups were the whole distribution strategy. Teachers working for the same handful of platforms, comparing notes, recommending tools to each other. Kahl says the business settled into roughly 30 new signups a day and never bought advertising: "We didn't ever have to pull ads or something, do these kind of things. We really were building almost exclusively word of mouth."
Simpson describes the same mechanism in an interview with They Got Acquired: "From the beginning, our subscriptions came in reliably through word of mouth. Teachers love to share helpful information so all of our growth was organic."
The unfair advantage here is worth naming precisely, because it is the transferable part. One of the two founders was a member of the customer group. She knew which Facebook groups mattered, what teachers called the problem, and which claims would sound credible. That is not marketing genius. It is access, and plenty of people have access to some group without realising it is an asset. It is also the classic answer to where first customers actually come from.
The price was designed to be an easy yes
FeedbackPanda opened with two tiers, $5 a month for up to 100 students and $10 a month for unlimited. After the first year they consolidated and raised it to $15. Kahl's reasoning, in the podcast: "we priced it at like, ended up at 15 bucks a month. So it was a very clear tool for people to buy."
Clear, because the maths did itself. A teacher paying $15 got back hours every week of work she was doing for free. There was a 30-day free trial so the habit could form before the card was charged.
Note what the price is not: it is not a percentage of the value delivered, and it is not benchmarked against competitors. It is a number small enough that nobody has to think. That is a legitimate strategy for a tool aimed at individuals, and a different problem from the one Builtplain describes in setting a first price you can defend, where the buyer is a business and the low number reads as low value.
The numbers, in order
- 2017: first version built in three to four weeks, nights and weekends.
- Day one: roughly 100 signups from a single Facebook comment.
- Nine months in: $20,000 monthly recurring revenue.
- By 2019: about $55,000 monthly recurring revenue, roughly 5,000 customers.
- June 2019: sold to SureSwift Capital. Seven figures, terms not disclosed.
Kahl repeats the $55,000 figure on his own site for the book he wrote afterwards, describing FeedbackPanda as "a $55.000 MRR business" with "thousands of customers" that he "sold it for a life-changing amount of money."
There is a market tailwind inside those numbers that he is careful to point out. The pool of online English teachers he was selling into grew from around 5,000 to more than 20,000 in his first year, and to somewhere between 50,000 and 75,000 in the second. He built a good product into a market that was multiplying underneath him. That is the piece nobody can schedule.
What it cost the person who built it
The exit is the happy ending; the road to it was not comfortable. Kahl told They Got Acquired plainly why they sold: "I was at the edge of burnout, and we wanted to diversify our wealth."
His stated regret is specific. They never hired anyone, so one person handled every support conversation for roughly 5,000 paying customers, for two years. On the podcast he describes the aftermath: "whenever I hear either the intercom noise or I see my phone ringing, I just get like a heightened pulse. It's just still anxiety, physical response." That was a year after the sale.
Anyone attracted to the one-person software company should read that quote twice. The model works. The support load is real, it arrives before you feel ready to delegate it, and the founder who stays solo out of pride pays for it in a currency that does not show up on a dashboard.
The repeatable checklist
If you strip FeedbackPanda down to its moving parts, this is what is left, and most of it is available to a person with a laptop and a community they belong to.
- Find work that a specific group of people does after hours, unpaid, every day.
- Build the smallest thing that removes it, and plug it into the tool they already have open.
- Charge a monthly price so obviously below the value returned that the decision takes seconds.
- Give a free trial long enough for the habit to set.
- Launch by telling the community you are already in, in the words they use.
- Take payment infrastructure seriously from day one, before there is anything to collect.
- Decide early who answers support at 200 customers, at 2,000, and at 5,000.
What is not repeatable: a customer market that quadrupled in a year, a co-founder who was the ideal customer, and a buyer arriving at the moment the founders wanted out. Kahl did not manufacture any of those. He noticed a problem two feet away, shipped in a month, priced it for an easy yes, and let 5,000 teachers tell each other about it.
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