Even a Small HR Tool with $40K Annual Revenue Found a Buyer — the Market Where "Minimum-Size SaaS" Sales Actually Close

Note: yen conversions in this article are rough estimates at ¥150 to the dollar.

The numbers

Item	Figure
Annual revenue	$40,000 (about ¥6 million)
Founder	Nick Holzherr
Buyer	KarbonPay (payroll SaaS)

Lessons and analysis

For an adjacent SaaS, what matters is not “smallness” but customer overlap. To KarbonPay, Air HR’s customers are precisely cross-sell targets for payroll. The acquisition closed on the fit of the customer list, not on revenue scale. This is a real-world data point in the micro-SaaS exit market, filling the gap between Microns’ $2,223 sale and Lionize’s $1.5M ARR sale.

A level worth remembering as an option for “winding down” an indie SaaS. ¥6 million in annual revenue can support a livelihood but is hard to grow. If a sale is possible even at this scale, then before “closing because it won’t grow,” you should always check the acquisition market first.

What the business and the deal looked like

Air HR is a simple HR tool offering small businesses management of employee records, leave, and personnel data. Founder Nick Holzherr (a serial entrepreneur who appeared on the BBC’s startup reality show) ran it as his “smaller product” alongside his main business. The buyer, KarbonPay, is a payroll SaaS — HR management and payroll are contiguous in both data and customers, so companies using Air HR become direct cross-sell targets for payroll.

Facing the reality of $40K a year

$40K a year equals roughly ¥500,000 a month. By Japanese standards, that’s around the threshold of “indie developer success” — and many developers assume “no way a business this small can be sold,” so they shut down or abandon products that have plateaued.

But as this case shows, what matters to a strategic buyer is not revenue scale. What was valued was “a working product + a real customer list + fit with an adjacent domain” — and when those three align, a deal can close even at ¥6 million in annual revenue. Conversely, no matter how technically excellent the product, without customers no buyer will appear.

Make “sell before you close” a habit

Indie developers’ exit decisions tend to jump straight from “it’s stopped growing” to “shut it down.” The practical lesson from this case is to insert one step into that flow: before closing, list three adjacent businesses that would want your customers, and reach out. With minimum-scale marketplaces like Microns available, the cost of finding a buyer has never been lower. A few months of effort could turn years of development into millions of yen.