KSeF for Accounting Firms: Handling 30 Clients Without 30 Logins

Why you log in 30 times (and why it isn't your fault)

KSeF has no concept of "an accounting firm with thirty clients." It knows taxpayers — and each taxpayer is a separate NIP and a separate working context. When you issue or download an invoice, you do it on behalf of one specific NIP, and the system has to know whose invoice it is handling each time.

That's where your daily rhythm comes from: open the Taxpayer App, set the context to client one, pull documents, switch to client two, pull, switch. Call it logging in or call it context switching — the effect is identical. Thirty clients means thirty manual passes, every single day.

This isn't a flaw in how you organize your work. It's a direct consequence of how authentication is designed in KSeF: an identity always operates within a single NIP. The question isn't "how do I log in faster," it's "how do I stop doing this by hand 30 times."

What KSeF itself says about access: permissions, certificate, token

On the state side, access has two parts. The client grants the firm permissions, pointing to the firm's NIP, and someone has to authenticate in the system — for example with a KSeF certificate, a qualified signature or seal, or Profil Zaufany. Authentication proves identity; the permissions decide on behalf of which companies you may act. A bookkeeping contract alone grants no access.

For contrast, here is how a token is built — pinned to a single NIP:

20260315-EC-A1B2…-NN | nip-1234567890 | F9E8…
                       ^^^^^^^^^^^^^^^^
                       a token is pinned to ONE NIP

A token is an application password tied to a single NIP. Thirty clients on tokens means thirty separate strings to generate, store, and babysit. A KSeF certificate is free and valid for up to 2 years.

What the Taxpayer App won't do for you

The free Taxpayer App solves authentication but not scale. It is built around one context at a time and works well when you are a single company handling one NIP. When you're a firm with thirty, each client is a separate entry, a separate switch, a separate manual download. There is no automatic background fetching, no queue and no shared task list.

It's a tool for the taxpayer, not for the firm — and that's fine. The Ministry shipped a free compliance gateway, not a client-portfolio management system.

What working with many clients looks like in Biurko

Biurko is not a workspace for accounting offices: there is no separate office area, no "Clients" list and no common screen showing every client's invoices. What it has is a simple model: one account, many companies.

An accountant joins a client's company as a free guest — one seat in every company, on every plan, including the free one — and switches between companies with one click. You log in once, to your own account, and what you may do in each company is set by the role the client gives you, for example Accountant.

Each company has its own KSeF connection. You set it up in one of three ways: with Profil Zaufany (the default — you sign an XML file at podpis.gov.pl), by uploading your own KSeF certificate, or by ordering a KSeF certificate from within Biurko. A session set up with Profil Zaufany does not renew itself — once it ends, the XML has to be signed again. For steady, automatic work, order a KSeF certificate in Biurko — after the first connection with Profil Zaufany — and use it for the connection. The connection is configured by the company's owner or administrator; the Accountant role cannot change it.

Automatic invoice import from KSeF is off by default. Once switched on in the company settings, it runs on a schedule (every 1, 3, 6, 12 or 24 hours, 6 hours by default), and the "pobierz teraz" (fetch now) button refreshes a company on demand. Biurko fetches invoices in which the company appears as the seller or the buyer.

What is missing is a single view of all clients at once. You enter each company separately and see its documents, registers and exports. The difference from the Taxpayer App is a different one: you don't switch context by hand and you don't download anything by hand, because the invoices are already waiting in the company. You export the invoice list and the purchase register to CSV or XLSX and load them into your own accounting software — there are no integrations with accounting packages.

The company pays, not the office: each company has its own plan, and the accountant's seat is free. Every new company gets 14 days of the TEAM plan without a card, then moves to the free FREE plan, where invoices and sending to KSeF are unlimited.

Illustrative scenario: a firm handles 20 limited-liability companies and 10 sole proprietorships (JDG) — 30 companies in all. In the Taxpayer App that's 30 manual context switches a day just to check whether new invoices arrived. In Biurko, invoices flow into each company in the background, and you switch to a company when you start working on it.

KSeF tokens and the end of 2026

Under the current rules KSeF tokens expire on 31 December 2026. At consultations on 9 June 2026 the Ministry of Finance proposed keeping them, but no regulation has been adopted yet, so moving to a KSeF certificate is the safer choice.

For a firm this means one thing: a 30-client process built on tokens may have to be rebuilt in December 2026, at the peak of year-end close. Biurko does not support tokens as a way to connect and never has — you connect a company with Profil Zaufany or a KSeF certificate.

Checklist — setting up multi-client work

1. Ask the client to invite you to their company in Biurko with the Accountant role. Your seat is free, and the invitation arrives by e-mail.

2. Agree who connects the company to KSeF. The connection is configured by the company's owner or administrator. Aim for a KSeF certificate in the long run, because a Profil Zaufany session does not renew itself.

3. Ask the client to grant your firm permissions in KSeF — in the Taxpayer App or in Biurko (Firma → Uprawnienia KSeF) — for issuing and/or receiving invoices. The Ministry confirms a grant separately, so it is not instant.

4. For the first user at a client company without a qualified seal, permissions are set up via the ZAW-FA form (the form that designates the first authorized person).

5. Enable automatic invoice import from KSeF in each company's settings — it is off by default.

6. Don't adopt client tokens as your target model — under the current rules they expire on 31 December 2026.

7. Review your list of active permissions and revoke them when a client relationship ends.

Wrapping up

The "30 logins" problem isn't only a login problem. It is a problem of working in one context at a time and downloading by hand. In Biurko you log in once, switch companies in one click, and invoices flow into each company in the background — once import is switched on and the company has its own KSeF connection.

We don't promise a shared dashboard for all clients, because there isn't one. If this model is enough for you, try it on your own portfolio: create an account at biurko.io — every new company gets 14 days of the TEAM plan without a card.

FAQ

Does an accounting firm need a separate KSeF login for each client? Not in Biurko: you log in once to your own account and switch companies in one click. Each company does have its own KSeF connection, configured by its owner or administrator. In the free Taxpayer App you switch context client by client.

How many KSeF connections does a firm serving many clients need? In Biurko each company has its own connection, so 30 clients means 30 connections. For steady, automatic work in the background, order a KSeF certificate in Biurko or upload your own. A certificate is free and valid for up to 2 years; Biurko warns you about its expiry on screen 30 days ahead and with notifications 7, 3 and 1 day before and on the day it expires.

Do KSeF tokens still work for accounting firms in 2026? Yes, under the current rules until 31 December 2026. At consultations on 9 June 2026 the Ministry of Finance proposed keeping them, but no regulation has been adopted yet. A token is pinned to a single NIP, which makes it impractical for many clients, and Biurko does not support it.

How does a client grant permissions to a firm in KSeF? In the Taxpayer App (Permissions module) or in Biurko (Firma → Uprawnienia KSeF), the owner or administrator points to the firm by its NIP and sets the scope: issuing invoices, access to invoices, or managing permissions. Signing a bookkeeping contract grants no access on its own.

Is the free KSeF Taxpayer App enough for a firm with 30 clients? Technically it keeps you compliant, but it works one context at a time, with no automatic fetching across companies. With 30 clients a tool that lets you switch companies in one click and imports from KSeF in the background is more practical. Biurko, however, has no common screen with every client's invoices.