Let me state the conclusion first. The first thing to decide in SaaS-ification for the solo CEO is not "what to build" but "what to get away with not building." And the real goal beyond that is neither to add features nor to own an impressive system. It is to win back your own time—to take your hands off the "work that isn't your real job," like drafting quotes, invoicing, transcribing daily reports, and reconciling inventory, and return that time to the work only you can do.
The cheapest and fastest path to that actually begins with "not building." First rule out whether off-the-shelf SaaS is enough, and build only the parts that are truly missing, small. This article is a practical guide to help solo CEOs and small businesses make this judgment with their own heads.
1. Don't mistake the objective — what you want is not a "system" but "time"
Many solo CEOs assume DX and SaaS-ification mean "building a cool system just for their own company," and that is where they stumble. But what you truly want is not the system itself. It is the "freed-up time" that system produces.
So your decision criterion always reduces to this one question.
"How many hours a month will this investment win back for me?"
Work backward from this question and priorities settle naturally. "Invoicing that takes five hours every week" is overwhelmingly higher priority than "a feature used only a few times a year." Start not with what's flashy but with the task eating the most of your time—this is the first principle of SaaS-ification for the solo CEO.
The "Cliff of 2025" that METI's DX Report sounded the alarm over is, at its root, the same story. Leave old, black-boxed machinery in place and maintenance alone eats up people and time until you can no longer move forward. This is not a problem for big companies only; the more of a solo CEO you are, the more you need a design that protects your scarcest resource—"your own time."
2. The overriding principle: "don't build" first — rule out whether off-the-shelf SaaS is enough
The most expensive mistake in a system-building consultation is going to the trouble of developing work from scratch when off-the-shelf SaaS could solve it. Never get the order wrong.
その業務は、あなたの事業の「差別化の核」か？
├─ No → 既製SaaS / 既製ツールで解く（作らない）
│ 会計・請求・勤怠・予約・顧客管理・チャット・
│ フォーム・EC など「どの会社も同じ」業務は作らない
└─ Yes → 既製品で要件を満たせるか？
├─ 満たせる → SaaSを採用し、足りない所だけ連携・拡張
└─ 満たせない → その「足りない一部」だけを小さく作る
※業界固有の商流・独自の業務制約がある場合
"Work every company does," like accounting, invoicing, booking, and customer management, can be handled by off-the-shelf SaaS that talented teams worldwide have polished over years, for a few thousand yen a month. Building this yourself is not only reinventing the wheel—it also means shouldering security and backups yourself, the worst possible choice for a solo CEO.
If you want to organize this "build or buy" decision along clear axes, reading the build-vs-buy, SaaS-vs-scratch, in-house-vs-outsource decision framework first will speed up your judgment.
How to spot a trustworthy advisor: a partner who answers "we can build it" to anything you ask is dangerous. An excellent builder is someone who can say, "off-the-shelf SaaS is enough for that; the only part you should build is this," and thus propose reducing their own order amount. Whether they can protect a solo CEO's limited budget is decided right here.
3. Business inventory — put "where the bottleneck is" into words first
Before deciding whether to build or buy, what you need is to lay out your company's work once and look at it. No difficult tools required. On a single sheet of paper or a spreadsheet, take inventory from the following angles.
| Angle to examine | Concrete question |
|---|---|
| Time | How many hours a week does each task take? |
| Errors | Where do transcription errors, double entry, and omissions occur? |
| Means | Right now, is it running on Excel / paper / fax / phone / LINE? |
| Key-person dependence | Which work stops if you (the CEO) go down? |
| Frequency | Daily, weekly, monthly, or a few times a year? |
Just filling in this table makes priorities largely visible. Work where "weekly, long hours, many errors, manual" overlap is the target to tackle first. Conversely, "a few times a year, short duration" work can stay manual for now. Not trying to digitalize everything at once is especially important for a solo CEO.
This inventory is exactly what we do together in the free DX assessment (30 minutes) described later. Putting "where time and errors are born" into words and deciding the order to tackle them—this becomes the foundation.
4. The three-layer model — don't think in "build everything / buy everything"
Once the inventory has settled on a target, decide which of the following three layers will solve that work. Many solo CEOs think in the binary of "① or ③," but the vast majority of realistic answers are the hybrid ②.
| Layer | How to solve it | Suited work | Sense of cost |
|---|---|---|---|
| ① Solve with off-the-shelf SaaS | Adopt and configure off-the-shelf tools such as accounting, invoicing, booking, and CRM | Standard work that is the same at any company | From a few thousand yen a month / roughly up to 100,000 yen upfront |
| ② SaaS + α (integration, automation) | Use off-the-shelf SaaS as the foundation and fill the gaps with no-code integration or small automations | "There's a SaaS, but it doesn't quite fit our procedures" | Small-scale development, roughly 500,000–3,000,000 yen |
| ③ Build only the missing core, small | Build from scratch only the part unique to your company that off-the-shelf products can't express | Industry-specific trade flows, unique business constraints | Only as much as needed, via phased ordering |
The lumber-distribution B2B SaaS I built single-handedly is a textbook case where ③ was justified. The multi-stage trade flow of "forestry → market → sawmill → precut plant → construction firm → manufacturer," and the separation of transactions and permissions across companies—these could not be expressed by off-the-shelf groupware or e-commerce, and building it myself made sense. Even so, I leaned the "foundation every company shares"—authentication, payments, email—on off-the-shelf services (Cognito and Stripe), and kept what I built myself to just the industry-specific logic. When I built the payment platform too, I concentrated development on the core that prevents the "accident that must never happen"—double-charging—and, as a result, achieved zero double-charges in production.
Applied to you as a solo CEO, it comes to this. Neither "build everything" nor "buy everything," but build only the part worth building. This is the one realistic answer that protects both cost and time.
5. How to "build small" — small starts and phased ordering
Even for the part you've decided to "build" under ③ (or ②), you must not aim for the finished form right away. The iron rule for protecting a solo CEO's money and time is not to build everything from the start.
5-1. Start with a minimal setup (MVP)
Once you've lined up all the features you want, pull out just the single minimal feature "without which the work doesn't run." Build only that first and use it in your actual work. Only by using it do you learn "what was truly necessary" and "what you were fine without." An "everything included" version built from imagination generates maintenance costs for the half of it that goes unused.
悪い進め方：要件を全部盛り込み、半年かけて一括開発 → 使われない機能だらけ
良い進め方：最も効く1機能を1〜2ヶ月で作る → 使う → 効果を見て次を足す
5-2. Split risk with phased ordering
Rather than pouring in several million yen at once, order in separate phases. Confirm the value in the first round, and if it feels right, move to the second. If it doesn't fit, you can stop there. This is the healthiest approach and minimizes the buyer's risk. The way to think about cost is summarized in the market rates and quote breakdown for system development, and the overall approach to procurement in the complete guide to procuring system development.
5-3. The "solo developer × generative AI" option
In recent years, an approach where a single developer uses generative AI (such as Claude Code) as an implementation accelerator, stripping away middleman margins and coordination costs to build small and fast, has become realistic. But the basis for the speed is not "the AI builds on its own"; it is that a human runs it through verification gates (tests, types, security review). As a buyer, always confirm whether the reason for the low price is "because verification is being skipped" or "because waste is being cut." On the pitfalls of AI-generated code, the vulnerability assessment of AI-generated code is also worth referencing.
6. Three mistakes solo CEOs tend to make
| Failure pattern | Why it's dangerous | The right way to face it |
|---|---|---|
| Trying to build everything at once | Budget and timeline both balloon, and unused features multiply | Start with the single highest-impact feature; carve it up with phased ordering |
| Full scratch from the start | You build even work that off-the-shelf SaaS could handle, and shoulder the maintenance | First rule out "don't build"; build only the core |
| Bloating requirements around a subsidy | You add unneeded features "because you can use one" and suffer under the later maintenance cost | Business improvement first; decide on a subsidy afterward, as a means |
The third one especially warrants caution. As also touched on in the buyer's guide to the IT Introduction Subsidy, if you think about a subsidy in the order "use it to the max because you're eligible," you tend to take on even features your company doesn't need. The order is always "① inventory → ② decide the needed improvement → ③ can a subsidy be used as a means to it." Don't reverse it.
7. A sense of cost and how to think about recouping the investment
For a solo CEO, the practical way to judge cost is to compare it not against the absolute figure but against "the time you can win back × your hourly value of time."
For example, suppose invoicing and payment management take five hours a week. If you tentatively set your time's value at 5,000 yen an hour, that works out to about 100,000 yen of time a month vanishing there. If you can halve it with off-the-shelf SaaS (a few thousand yen a month) plus a small integration, you can project that the investment pays back in a few months.
*The hourly rate and reduction range cited here are merely examples of the way of thinking; the effect varies by the nature of the work. Actual ROI must be estimated based on your own operational data. Conversely, be wary of any partner who promises a numbers-first "X% reduction."
And don't forget the cost of doing nothing. The "Cliff of 2025"-style debt of continuing old ways keeps shaving off your time every month in an invisible form. On technology selection that takes industry-specific circumstances into account, see also the technology-selection framework for legacy-industry DX.
8. How to proceed — start with a 30-minute "free DX assessment"
Doing all of this alone is hard. So, as a first step, I offer a free DX assessment (30 minutes). I hear out your current situation online and later send you an "assessment memo." No sales pitch. You're welcome to take just the assessment and go.
What you can take home from the assessment is the very judgment this article has been explaining.
- Putting the business bottleneck into words — where time and errors are born (the inventory in Section 3)
- A proposed order to tackle things — whether off-the-shelf SaaS is enough / whether development is needed / whether to hold off for now (the judgments in Sections 2–4)
- A rough cost range and a phased-ordering plan — how to carve it up to start small (Section 5)
- The next step if you proceed in-house — a path to move forward even without placing an order
To summarize how to proceed, it comes to this.
① 無料DX診断（30分） … 現状を整理し、診断メモを受け取る
② 診断メモで自走 or 発注 … 既製SaaSで足りるなら、そのまま社内で導入
③ 開発が要る所だけ小さく … 足りない核だけ、スモールスタートで段階発注
What matters is not starting from "building." First make visible where your company's time is being taken, solve much of it with off-the-shelf SaaS, and build only the part that is truly missing, only as much as needed. Just keeping this order makes a solo CEO's DX proceed astonishingly light-footed—and safely.
Let's win your time back for your real work. Let me help you organize it, starting with that first 30 minutes.