Solopreneur case studies — 3/10
Solopreneur and side-business cases
49–72 of 239
Skeb: The "Personal Hobby Service" That Sold All Its Shares for ¥1 Billion — Settling the Risk of One Person Holding ¥200 Million a Month in Transactions
Skeb, which its founder called a "personal hobby service," reached 1 million registered users and roughly ¥200 million in monthly transaction volume in just over two years, then became a subsidiary of Jitsugyo no Nihon Sha in February 2021 for ¥1 billion. The top reason for selling was not stalled growth but payment-settlement risk.
Leadverse Gets All Its Customers From Reddit, and 90% of Its Costs Are LLM Fees — $3,300 MRR Built Between a Day Job and a Newborn
Leadverse, an AI tool that finds prospects on social media, reached $3,300 MRR and 130+ paying customers ten months after launch. Every dollar of revenue comes from Reddit, and LLM API fees make up about 90% of operating costs.
AI Directories: $10,000 a Month from One-Time Purchases, Built on a Chore He Automated
A service that submits AI products to 100+ directories by hand. Built for the founder's own use, it became the biggest earner in his portfolio, now at $10,000/month across products. But the three numbers he publishes — interview, pricing page, revenue page — don't match.
Questgen & Supermeme Today: 2.5 Million Signups, $6,500–7,000 a Month — Three AI Tools Down From a $100K Peak Year
Three AI tools run by a data scientist alongside his day job. Combined signups exceed 2.5 million, yet current monthly revenue is $6,500–7,000 — down from the 2025 peak of $100K a year.
Abbey Road: He Sold His Own Assets to Take Over a 20-Year Rakuten Watchband Store
Katsuhito Saiki, who worked at a seafood trading company, took over "Abbey Road," a watchband shop that had run for 20+ years on Rakuten Market. He'd once passed on the listing because it exceeded his budget, but returned to it; when a loan from the Japan Finance Corporation was rejected, he sold off his own assets to raise funds. Negotiations spanned about 1 year and 8 months.
Is a coin laundry passive income? ¥150,000-500,000 a month, 7-10 year payback — an owner's numbers
A current owner running a coin laundry as a side business published their income statement: initial investment of ¥13-22 million, monthly revenue of ¥150,000-500,000, fixed costs of ¥250,000-530,000, take-home of a few tens of thousands to over ¥100,000 per month, with a 7-10 year payback period. We examine content in which the operator personally dismantles the "passive income" image.
manablog at ¥1,000,000–1,500,000/month, and two sites left idle 3–4 years before closing — the numbers Manabu published under his real name
manablog earns ¥1,000,000–1,500,000/month at 500,000 PV, with one article alone worth roughly ¥500,000/month, while two other sites earning ¥100,000–150,000/month closed after 3–4 years of neglect.
Lenny’s Newsletter: 377K Free, 18K Paid, $2M+ a Year — 450 Paid Subscribers in the First 6 Weeks After Going Paid
Lenny Rachitsky's newsletter earns $2M+/year from 377K free and 18K+ paid subscribers (a 4–5% conversion rate). Six weeks after going paid on April 7, 2020, it had 450 paid subscribers. The turning point wasn't the paywall itself — it was rebuilding the product as a Slack community.
22 Udemy Courses, 8 Bestsellers, $2,124 a Month on Average: Building a "Shelf of Courses" on a Global Platform
A Udemy instructor teaching coaching and video production published a revenue report covering 22 courses (8 of them bestsellers). Instructor income averages $2,124 a month (about ¥319,000), of which roughly ¥150,000 comes via Udemy itself. He discloses down to per-course profitability: unsold courses make ¥1,000 a month while bestsellers make tens of thousands of yen.
Damon Chen: Bought a GitHub Repo for $20K, Grew It to $1.5M ARR — the “Buy, Don’t Build” Indie Playbook
Former engineer Damon Chen grew Testimonial.to to over $2M cumulative revenue in four years, then in the early ChatGPT boom bought a pre-revenue repository (now PDF.ai) for $20K. Repositioned as "AI you can chat with about PDFs," it grew to $1.5M ARR within months. A defining example of indie development that buys the seed instead of building from scratch.
8 failures, 3 hits in 5 years — the turning point where a solo developer with ¥0 revenue reached ¥200,000–¥1,000,000/month
Of 8 failed products earning ¥0 to a few thousand yen, one successful paid learning service hit ¥200,000–¥1,000,000/month within six months on 50–200 users. Laying out all 11 side by side reveals what actually split them.
A high schooler's paid Discord bot nets ¥12,000/month profit — reading the logic behind pricing ¥500 on top of a ¥320 cost
Entering a Discord text-to-speech market full of free bots at ¥500/month, cost about ¥320 per 200,000 characters, and ¥12,000/month profit by year two. Even the signup pace is quantified.
The Revenue Record of 9 Udemy Courses — the First Took 100 Hours and Made $165, and What It Taught Produced a "¥1.5 Million Course"
Udemy bestselling instructor Naoto Takizawa published real data across 9 courses. His first course took about 100 hours and earned $165 (about ¥20,000) in a year, but a later course refined through iteration cleared $10,000 (¥1.5 million) in profit. Monthly students grew from 34 in the first month to 563 within a year. The explanation of the mechanics — including revenue shares (97% for self-referred sales / 37% for Udemy-sourced) — is invaluable.
SEO Blog Backlinko, 500K Monthly Visits, Sells to Semrush for Seven Figures: The Rare Strategy of Doing the Opposite of Mass Production
Brian Dean's SEO blog Backlinko drew 500,000 monthly visits with a strategy of publishing few articles but polishing each one to perfection, and was sold to SEO tool giant Semrush for seven figures (hundreds of millions of yen). A classic case in content strategy: winning at the polar opposite of "write a lot."
From ¥100 to ¥100,000 a Month in Three Years: The Quiet Compounding of an Ads-Only Tool App
The tool app built by Wakanao, a solo developer from Hokkaido, earned about ¥100 a month at launch. Over three-plus years of persistence, MAU grew more than 100x and revenue reached ¥100,000 a month from AdMob ads alone. A record of the growth curve of an app with no paid features and no marketing — one that simply stayed on the store.
Four Rental Spaces Generating ¥360,000 in Monthly Profit. 30% Fees, ¥450,000–700,000 Upfront — the Going Rates of the Hourly-Rental Market
Serial entrepreneur Kenji Sato published both his track record — four rental spaces producing ¥360,000 in monthly profit — and a market-wide picture of the going rates. Hourly rates cluster at ¥3,000–6,000, platform fees run 30–35%, upfront costs are ¥450,000–700,000, and roughly 30% of operators lose money in year one. A document that lays out the industry's P&L template before you enter.
Screenshot-Annotation Tool InstaCap Sold for 6x Revenue to a Serial Entrepreneur: Why It Beat the Standard Micro-SaaS Multiple
InstaCap, a tool for annotating and sharing screenshots, was sold by founder Samee Hassan to serial entrepreneur Joe Speiser at 6x revenue. Material for thinking about what conditions produce a multiple above the standard 3–5x range.
Shopify App Portfolio Plug in Useful, 37,000 Users, Sold to SureSwift: An App Business Built by "The SEO Guy"
Plug in Useful, a portfolio of Shopify apps run solo by Daniel Sim with 37,000 users, was sold to SureSwift Capital, a serial acquirer of SaaS businesses. A real example of a specialist-turned-founder building an ecosystem by turning his own SEO expertise into apps.
Sidekiq: Open Source to $7M+ a Year, Solo — the Finished Form of a 20-Year “OSS + Paid Edition” Strategy
Mike Perham, creator of Sidekiq, the open-source background job processor for Ruby, has run a free-OSS-plus-paid-Pro/Enterprise model entirely alone and grown it past $7M (about ¥1.05 billion) in annual revenue (in 2023 he said it was "closer to $10M than $1M"). The pinnacle of commercializing OSS with zero employees.
Two Real Records of Renting Out a Home Parking Space — ¥741/Month Average in the Countryside, ¥4,500/Month in the City. An akippa/Toku-P P&L Breakdown
Two people rented out their home parking spaces via akippa and Toku-P. A regional residential street (20 min walk from the station) saw 32 days of use in a year — ¥741/month average, ¥2,164 best month. The urban case filled 3–4 days a week for about ¥4,500/month. Measured values for a "zero-investment, zero-effort" side hustle where fees (akippa ~54% / Toku-P 30%) and location decide everything.
Streets of Rogue: An Indie Game Built on $18,000 Sold for Roughly $6.5M — the Six-Year Story
Streets of Rogue, a roguelike made by a solo developer with $18,000 of his own money, sold over one million copies, generated $8M in lifetime revenue, and was acquired by tinyBuild for $6.5M in June 2021.
Why We Buy: Subscribers Up 1.4x, Revenue Up 3.3x — the Structure Behind a ¥150M Year in 2024
Marketer newsletter "Why We Buy" grew from 50,000 subscribers and $300K in annual revenue to nearly 70,000 subscribers and roughly $1M. This piece examines the mechanics behind subscribers growing 1.4x while revenue grew 3.3x.
Backlink-Design SaaS SEOJet Doubled Its Price in the Year Before the Sale — What the Prep Work Looked Like
Founder Adam White sold SEOJet, a tool for designing backlink anchor-text profiles, for double the price he originally expected, by doing extra groundwork right before the sale. A real example showing that "the year before you sell" moves the sale price more than anything else.
SearchSEO Sold for About $300K: The Exit and the Limits of a "Gray-Hat SaaS"
SearchSEO, a SaaS that manipulated search-result click-through rates with simulated traffic, was sold by founder Martin Delannoy to individual buyers for around $300K (about ¥45M). Material for thinking about the pricing and timing of a business carrying terms-of-service risk.