Plumm · own product

Online accounting instead of Excel: one panel, the tax office, and a human in the loop

Author: Marcin Bochenek · Updated: 2026-08-24

A sheet of invoices, a separate JPK tool, mail to the accountant and ZUS dates in your head is not “flexibility”. It is five sources of truth. Plumm is my product: e-invoices to the authority, filings, CRM and a tax assistant that hands hard cases to a bookkeeper. Estimates: 12–20 h/month* less paperwork at a regular volume; PLN 300–600/month less than a traditional office for a sole trader (plans from PLN 149). This is not a “street client” case. It is a product I maintain and you can click.

Excel in accounting breaks in silence, not on a chart

A formula drifts in April; you notice in May when the office is already waiting. An accounting firm can be slow (two days per question) and expensive relative to sole-trader volume. Neither a sheet nor “I will send scans on WhatsApp” gives one status: did the invoice leave, did the return go, is the contribution calculated.

• One login instead of three programs.
• An e-invoice that is compliant immediately, not an “add-on”.
• Deadlines in a calendar, not a notebook.
• A tax question in Polish — with escalation, not a hallucination left in a client email.

HITL, not “we will drop ChatGPT onto the ledger”

The Plumm assistant does not sign returns for you in the dark. Fast questions — the model. A dispute, an interpretation, a fine risk — a human. Same philosophy as human-in-the-loop automation: allowed scope, a log, escalation. A public chat without a policy is a leak and a hallucination. I cover that in implementing ChatGPT.

What this article is not

1. Not an affiliate “best accounting 2026” round-up.
2. Not a promise that every sole trader saves 20 hours — hence the asterisk.
3. Not an offer to white-label Plumm into a third-party office I do not run in public.
4. It does not use I DRIVE CARS or Agentic as accounting proof — wrong product.

Live URL: plumm.pl and app.plumm.pl. If you need a panel for another process (not accounting), we return to Ops and PLN 60–180k+.

For whom a sheet is still enough

A handful of invoices a year, no staff, a family bookkeeper who hits the deadline. Then Plumm may be overkill. I do not push a subscription when ROI does not close — same rule as websites. When volume grows and late-filing fines cost more than the plan, the maths flips.

Neighbourhood with the site and the funnel

plumm.pl collects plans and explains the product. It is not a PLN 2,000 brochure detached from the panel. If you build your own SaaS, the site and the app are one system. If you only want an accountant’s brochure — another package, another goal, no fake e-invoice engine.

What Excel still does well — and where a sole trader starts paying in time

Online accounting instead of Excel does not mean the sheet is stupid. Excel is excellent when one person handles low volume and remembers what column G means. It breaks when KSeF arrives, PIT/VAT/ZUS deadlines, illness, leave, and “I will send it tomorrow”. Then a mistake is not cosmetic. It is interest, a summons, or a night before the deadline. I build Plumm as my own product for sole traders, not as a rollout to twenty offices I cannot show.

The estimate of 12–20 hours a month and PLN 300–600 less than a traditional office is a product hypothesis, not a certificate for your firm. The asterisk stays. I do not paste fake reviews that “the office robbed me, Plumm saved me”. If you have an accountant who handles it and picks up the phone — I will not talk you into betrayal out of ideology. I talk when the sheet and deadline panic are your standing ritual.

• E-invoices that must arrive, not “a file in mail someone will lose”.
• A calendar of contributions and tax you do not keep in your head.
• An assistant with escalation to a human — not auto-send without a log.
• Export and history if you change your mind. Lock-in with no exit is an enemy of a sole trader.

HITL in accounting: the model does not sign the return for you

An assistant that proposes and a human that approves is the only adult setup I accept. A hallucination on an invoice is more expensive than a slower click. That is why escalation in Plumm is not a product shame. It is a feature. Human-in-the-loop automation describes the same contract in other processes: allow-list, log, who clicked “issue”.

I do not promise AI will “handle the books”. I promise I do not bolt a chat onto a naked form to look modern. GDPR and responsibility for the return stay with you and with a tool that can show a trail. If you want magic with no trail — we are not a match.

When an office still beats an online product

When you have a company, payroll, fixed assets and disputes a sole-trader Plumm does not cover. When you need a human who knows your history with the tax office and picks up at 22:00 in April. An online product does not impersonate a law firm. If someone sells “full AI accounting for everyone” with no legal-form limit — read the contract twice. I write limits on the page, not in footnote 8.

An office also wins when you refuse to operate a tool. Plumm assumes you will click. If you hate clicking more than you hate the service invoice — stay. That is not contempt. That is qualification. Better not to have you as a user than to have you as an angry ticket because you thought “it books itself”.

How to judge whether to leave Excel at all

1. Count last month’s hours: invoices, mails to the accountant, corrections.
2. Write down how often deadlines were “close” or late.
3. Check whether anyone besides you can open the sheet without breaking it.
4. Decide if you want a product with a log, or a human with a phone.

If after that card you still prefer Excel — keep it. If you prefer a human — call an office. If you want to see how it looks in a product I maintain myself, open Plumm. I do not invent client case studies I cannot name. That is the whole honesty you can afford with me and with yourself.

What the “office / sheet / Plumm” decision looks like

On paper: last month’s hours, close deadlines, whether anyone besides you can open the file. If you want a phone at 22:00 in April — an office. If you refuse to click — an office or a disciplined sheet. If you want a product with a trail, e-invoices and escalation — open Plumm and judge yourself. I do not lock you with an ROI slide. The 12–20 h and PLN 300–600 hypothesis stays a hypothesis until you measure your month. Online accounting instead of Excel is a tool, not a religion. The model does not sign PIT. You do. That is why HITL is not product shame. It is the only honest setup.