Certean: Product, team and how it was built

Solo founder · sold 17 months after launch

It solved one narrow and repeated task that every company has at the end of each quarter: find all invoices and give them to the accountant. It read the invoices where they already were, in the inbox and on supplier websites, instead of asking people to forward them, and it let customers write their own checking rules in plain language. Stripe data shows monthly revenue rising from US$12,631 in November 2025 to US$18,970 in January 2026.

Team of 2 to 10 · 33 months after launch, revenue falling

The product goes where the customers already are: a shop owner does not install a new app or learn accounting software, but writes into a chat. The founder wrote of having worked as a data scientist at a microloan company and of running a café, so the founder knew both the bookkeeping problem and the reason banks ask for records.

Solo founder · 19 months after launch, revenue growing

The founder, a digital nomad, had collected more than 1,000 receipts from many countries to track his own spending, and built the app for that use. It reads every line item instead of only the total, which matters for travellers with receipts in foreign scripts and currencies. Small, steady releases (25 versions between 21 January and late October 2026) and a translation of the app into 52 languages widened the market without a team.

Team of 2 to 10 · 24 months after launch

It picked work that large regulated companies had failed to automate for years and that tolerates almost no errors. Instead of letting a model decide each step, it turns the expert's procedure into fixed program steps, which makes the result predictable and cheap to run. A few large customers, sold directly, can pay for a very small team.

Started small, grew after funding · 25 months after launch, revenue growing

Every GmbH and UG in Germany must keep books, file VAT returns and produce annual accounts, and most pay a tax adviser's office to do it, the company's press release says. mika puts AI on the routine part, keeps people on the checking, and sells it as a monthly subscription that the price page lists from €49 net. It chose one narrow customer, the small limited company without its own finance staff, and the customer count grew from about 400 at the start of 2026 to more than 750 in September 2026, the company said.

Team of 2 to 10 · 7 months after launch

Chasing late invoices is repetitive work that finance teams do by hand in spreadsheets and email. Cleavr connects to tools that companies already use, such as Pennylane, Stripe and SAP, so a customer can start without a migration, and the company says setup takes under a day.

Solo founder · 37 months after launch, revenue growing

It launched the obvious application of a new model within weeks, with a pricing page on the first day. The founder built the parts around the model instead of a model, so every model upgrade improved the product for free. Then it moved from a consumer toy to business customers who stay.

Team of 2 to 10 · 45 months after launch, revenue falling

Said US$19K a monthRecords US$9.6K in JulyDid not hold

It appeared in January 2023 inside Google Slides, a program where people already work, when writing slides from one sentence was new, and users showed it to each other without paid advertising. A blog about presentation topics then brought about 80% of new users from Google search, by the founder's account. Both channels weakened: search traffic fell, and Google added the same function to Slides. The verified total is real, and so is the fall: monthly revenue fell by half between February and July 2026.

Solo founder · 11 months after launch, revenue flat

The founder had written a marketing blog for ten years, so his own readers bought on the first day. He built the first version in 8 weeks with the no-code tool Bubble, because he had no money for developers. He sold one thing that the model makers do not sell: all of their models in one subscription.

Solo founder · 35 months after launch, revenue falling

It reached people inside the chat app that they already open all day, so capturing an idea on a phone took one voice note. It aimed first at Notion users, whom the company told that ideas get lost on the phone. Ads on Facebook and Google then paid for fast growth in early 2026, until the founder stopped them in August 2026 because the costs were larger than the revenue.

Team of 2 to 10 · sold 17 months after launch

Four founders, two of whom had built the drinks-delivery start-up Winelivery, looked for a profession that works with a large, fast-changing body of rules and had not yet adopted AI, and chose Italian accountants and labour consultants. They tested a first version with practitioners and sold monthly subscriptions. In October 2025 TeamSystem, an Italian maker of software for accountants, bought the majority of the company; its press release said Normo.ai had €1.3 million of revenue in 2025.

Solo founder · 44 months after launch, revenue falling

A studio portrait needs a photographer, a booking and days of waiting. AI SuitUp sold the same result, a photo for LinkedIn or a résumé, for a one-time price from early 2023, with a money-back guarantee on the larger packs. It narrowed the offer to one use, professional headshots, and then built a landing page for almost every profession and a version for company teams. Stripe records US$648,649 of payments in total, but only US$35,743 of it in the last 12 months, so most of the money came in 2023, 2024 and 2025.

Team of 2 to 10 · 10 months after launch, revenue flat

The founder had worked as a screenwriter and knew which part of the job is tool work: the page format, and keeping characters and scenes consistent across a long draft. He built the editor around that work and kept the AI in the role of a helper. He says Claude Code wrote all the code. The beta grew through invite codes that users earned by posting about it, and monthly revenue rose from US$5,136 in May 2026 to about US$46,000 in August and in September.

Team of 2 to 10 · 11 months after launch, revenue falling

It took a narrower job than the general AI design tools, mobile apps only, for people who build apps without design skills. The three founders reused what they had learned from four earlier design tools, built it in three weeks, and showed finished designs on X before the launch. Each new Gemini model gave them a better result and a new demo to post.