In proceedings with a value equal to or greater than the EU thresholds, you must sign the bid and the ESPD exclusively with a qualified electronic signature. In national procurement procedures (below the thresholds), the law also permits a trusted signature and a personal signature, but it is the qualified signature that is valid in both cases—and it is the only one that also allows the public procurement contract itself to be concluded electronically. We explain the reasoning behind each step and how to avoid losing an offer due to a procedural error.
The Public Procurement Law (Act of September 11, 2019, hereinafter: PZP) has moved communication between the contracting authority and contractors online. Bids are submitted via the platform e-Orders or the buyers’ shopping portals, and a document without the proper signature is treated as if it had not been submitted. In practice, this means Rejection of the offer without the possibility of amending it (Article 226(1)(3) of the Public Procurement Law) — regardless of how good the price was.
The rule is simple:
The current EU thresholds are announced by the President of the Public Procurement Office in a notice updated every two years. For the years 2026–2027, they are: 140,000 euros (supplies and services for central government), 216,000 euros (including local governments), and 5,404,000 euros (construction works); as of January 1, 2026, the Act itself applies to contracts with a value of at least 170,000 PLN net. Before submitting a bid, always check the value of the procurement in the notice or the tender documentation.
| Document | Performance ≥ EU thresholds | National Proceedings |
|---|---|---|
| Offer | only a qualified digital signature | qualified / trusted / personal |
| EAT (ESPD) | only a qualified digital signature | Not applicable (statement under Article 125 of the Public Procurement Law — same as a bid) |
| Power of Attorney | the principal's qualified digital signature | such as an offer (or a notarial certification) |
| Procurement Contract | only a qualified digital signature (or a paper signature) | only a qualified digital signature (or a paper signature) |
ESPD (European Single Procurement Document) This is a self-declaration by the contractor, which, in procurement procedures exceeding EU thresholds, replaces certificates and attestations during the bidding phase. It is submitted electronically—most often as an XML or PDF file generated on the eESPD platform—and appends a qualified electronic signature.
Practical tip: Sign PDF files in the PAdES (a signature „inside” the document), and XML files — in the format XAdES. If you are using XAdES in the external mode, be sure to provide the ordering party with both files: the document and the signature file. You can read more about the differences in the article PAdES and XAdES — Two Forms of Digital Signatures.
The most common mistake? Editing a document after signing it — this invalidates the signature. The order is always: final version → signature → shipment. A signature applied to a ZIP file covers all files in the archive (§ 8 of the Regulation on Technical Requirements), but it is safer to sign each file separately.
Pursuant to Article 432 of the Public Procurement Law, a public procurement contract requires in writing, under penalty of nullity. In the digital world, its equivalent is exclusively an electronic form bearing a qualified electronic signature from both parties (Article 78¹ of the Civil Code). An increasing number of contracting authorities—including schools, preschools, and local government entities—are signing contracts in precisely this manner: without printing, couriers, or scanning. This also applies to addenda and minutes that require written form.
In public procurement practice, it is rarely a „company” that signs—it is a specific individual who signs, and the contracting authority meticulously verifies that person’s authority. Three typical scenarios:
Best practice for bidding departments: Keep a record of the validity of all signers’ certificates. A certificate that expires during the process (e.g., between the bid submission and the signing of the contract) can bring the entire process to a halt—renewal takes only a moment, but only if someone remembers to do it.
A qualified digital signature is useful not only for the bid itself. In a typical procedure, the following are also signed electronically: explanations of the bid’s content and any abnormally low price, evidence submitted by the bidder, and updated statements; commitments by third parties to make resources available; a bid bond submitted in the form of an electronic guarantee (here, the signature is provided by the guarantor—a bank or insurer), and finally, the contract and its annexes. The further into the process one goes, the more often it turns out that a single „company” certificate is not enough—explanations with a two-day deadline cannot wait until the CEO returns from a business trip. That is why well-established bidding departments equip at least two people with mobile signature capabilities.
Both signatures offered by podpisano.pl, an authorized partner of Certum, are eligible and fully accepted on e-Zamówienia and other procurement portals:
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In procurement procedures with a value equal to or greater than the EU thresholds—only a qualified electronic signature is permitted. In national procurement procedures below the thresholds, a trusted signature or a personal signature from an e-ID card is also acceptable.
Yes. The ESPD must be submitted in electronic form with a qualified electronic signature—this applies to procurement procedures above the EU thresholds in which the ESPD is required.
The agreement must be in writing to be valid; therefore, it can be concluded electronically only if both parties provide a qualified electronic signature. A traditional signature on paper remains an alternative.
Only in domestic procurement procedures, below the EU thresholds. In EU tenders, a bid signed with a trusted profile will be rejected.
PDF files should preferably be signed using the PAdES format, and XML files (e.g., JEDZ) using the XAdES format. When using an external XAdES signature, provide the contracting authority with the document along with the signature file.
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