The office of tax accountant Yun Jae-seong (39) was quiet. It stayed quiet even during the VAT filing crunch, when deadlines pile up. Instead of stacks of paper, a single tablet stood propped on his desk, its screen showing a list titled "Today's Deadlines." A client name, a filing type, and a red D-2 chip. He swiped across the screen once and said, "Two of them today."
A solo practice managing 180 clients alone. Around this time of year, most offices are buried in paperwork and deadlines even with two or three staff pitching in. And yet his office was calm. When asked his secret, he turned the tablet around to show me. "This screen. I built it." He said he'd never learned to code.
180 clients, you said. How did you used to manage deadlines?
Excel. I'd make a sheet per client, write in the filing schedule, color-code the ones coming due. The problem is, it isn't alive. I had to open it every day and scan it with my eyes to see what was urgent today, and remember which sheet I'd copied yesterday's receipt into. With 50 clients it worked. Once it passed 100 — I started to slip.
Once I missed a withholding-tax payment deadline for a client. A penalty was added. The amount wasn't huge, but the feeling when I got that call — "I trusted you" — that stayed with me for a long time. That's when I realized: as long as I'm running on memory, the more clients I take on, the more accidents I'll have.
So you built your own tool. Did you learn to develop?
No. That's the whole point. I can't write code. All I did was decide what was needed. What should appear on the screen, what counts as urgent, where a receipt should go when it comes in — I know that because I've done tax work for 20 years. Translating that into something a computer understands was always the problem, and that's the part makemind took over.
I didn't draw the screen — I described it. Put the clients with deadlines coming up at the top, with red chips. Below that, one line for what to handle this month. When I write down what to show and where, like that, it becomes the screen. I didn't do any design; I just said what I needed.
"I didn't draw the screen — I described it. Because I know best what matters. I can't draw, but I can talk."
Can you show us what actually happens behind that screen?
Of course. The screen is really the very last step. There are four stages before it. A receipt comes in, it accumulates per client, today's urgent items get filtered out, the notices go out. I didn't design that flow — I only decided what goes into and comes out of each stage.
First stage — how do receipts and documents get in?
Clients send me photos of receipts over KakaoTalk. Some send PDFs, some just snap a photo by hand. I used to look at each one and copy it into Excel myself. Now, whether it's a photo or a PDF, I just upload it and the text gets read automatically — "March 12, 2026, office supplies, 84,000 won," like that — and comes in already organized.
What matters is that which document from which client it came from gets attached along with it. Later, when I wonder "where did this number come from?", I can trace it back to the original receipt. In tax work, evidence is everything.
Next, where does each client's history accumulate?
For each client there's a place where the facts pile up in chronological order. Things like "March sales were this much," "a filing like this around the same time last year," "the point when the CEO changed," "not enrolled in the Yellow Umbrella mutual aid." And every fact carries its source — which document it came from.
This is the crucial difference from Excel. Excel only shows the current state; this remembers change. Something like "this client's sales jumped 30% over last year — looks like the point to move from simplified to general taxation" is held by the data itself, without me comparing line by line. Twenty years of judgment from inside my head, the data now remembers in the same shape.
So how does "Today's Deadlines" appear?
Every dawn it runs through all 180 clients once. How many days until the deadline, are any documents missing, any odd jumps in sales. It scans by these criteria I set and surfaces what's urgent today.
It doesn't just look at dates. Yesterday the screen showed "Park Ji-won Tax Firm — VAT D-2, 1 sales omission to verify." It tells me a deadline is near, but it also points out that one thing is missing from the flow. If I'd been going through all 180 clients one by one, I'd never have caught it. Because it suspects first, all I have to do is verify.
This is the screen I look at every morning. At the top, clients with deadlines coming up, each with its D-day chip; below, one line for what to handle this month. See that black card? "Yellow Umbrella not applied at 12 clients, average tax savings 840,000 won." That, too, isn't something I counted by hand — it surfaced it on its own. If I call those 12 clients, they save on taxes and I earn their trust.
What about the notices and reminders?
For clients with a deadline coming up, a draft notice gets prepared automatically. "Lee Seo-yeon Design, your withholding-tax payment deadline is five days away. This month's labor-cost filing details are as follows…" — not by filling in blanks, but by putting in that client's actual numbers.
I look over the draft once — I always do this review, because tax work has my name on it — and if it's fine, it goes out over Kakao. Writing a single notice message used to take me 10 minutes. Now I just review and press send.
To sum up — what did you, Mr. Yun, do, and what did makemind do?
What I did was the judgment. What matters, in what order to look, what anomalies to suspect, what to put in a notice. Only someone who's done 20 years of tax work knows that. What makemind did was carry that judgment.
| Stage | What I decided (20 years of judgment) | What the tool did |
|---|---|---|
| Document input | Which items to extract | Read text from photos and PDFs and organized it |
| History building | Which facts to keep | Stored per client in chronological order, with sources |
| Deadlines & anomalies | What to suspect | Scanned 180 clients daily to surface the urgent and the odd |
| Notices | What to say | Drafted and sent notices with each client's numbers |
| Screen | What to show, where | Rendered it to screen exactly as described |
I only filled in the left column. The tool took the right side. Work that would have taken months to learn to develop, or tens of millions of won to outsource — I did it just by putting my judgment into words.
What changed the most?
My peace of mind. I used to be anxious all the time. That feeling of missing something. The more clients I had, the bigger it grew. Now — one look at the screen in the morning and I can see everything urgent for today. What I might miss is right there on the screen, so there's nothing to be anxious about missing.
And I'm not afraid of taking on more clients anymore. Whether it becomes 200 or 300, I don't have to memorize any more. The data does the memorizing; I just do the judging. Growing the practice no longer means growing the accidents.
"It used to be that more clients meant more anxiety. Now, more clients doesn't mean more for me to remember. That difference is what decides whether you can keep doing this work or not."
Any advice for other tax accountants?
Don't start big. I didn't build all of this from the start either. I started with a single line — "Today's Deadlines." A screen that just showed clients and their due dates. Once that worked, I added receipt input, then the surfacing, then the notices — one column at a time.
Here's the key. What you know best is your work, not coding. You just have to describe what you know so well. You can't draw, but you can talk. A screen built by someone like me, who can't write a single line of code, is holding up my whole practice right now.
makemind.dev "Field" — the person who knows the domain best, building their own tool with their own hands. Yun Jae-seong's "Today's Deadlines" was built not from code but from judgment.