Qualified Electronic Signature (QES): What It Is, How to Get One and What It Costs

A qualified electronic signature (QES) is the highest level of electronic signature under the EU eIDAS Regulation and the Swiss ZertES law. It is an advanced electronic signature created with a qualified signature creation device and based on a qualified certificate, and Article 25 of eIDAS gives it the same legal effect as a handwritten signature across the EU.

Most business documents do not need one. This guide explains what makes a signature "qualified", when you need one, how to get one, what it costs, what to look for in a QES provider, and how to send a QES request in Sign.Plus.

What is a qualified electronic signature?

eIDAS defines electronic signatures, advanced electronic signatures and qualified electronic signatures. "Simple electronic signature" (SES) is the common name for an electronic signature that does not meet the advanced or qualified requirements. Each level adds requirements on top of the one below it.

eIDAS defines a QES as an advanced electronic signature that is created by a qualified signature creation device and based on a qualified certificate for electronic signatures. In practice that means three building blocks:

• An advanced signature. It is uniquely linked to the signer, capable of identifying them, created with signature data the signer can, with a high level of confidence, use under their sole control, and linked to the document so that any later change is detectable.
• A qualified certificate. Issued by a qualified trust service provider (QTSP) only after the signer's identity has been verified, in person or by an equivalent method such as video or a qualified eID.
• A qualified signature creation device (QSCD). Certified software or hardware that meets the security requirements in Annex II of eIDAS. It can be held by the signer, such as a smart card or USB token, or managed remotely by a QTSP on the signer's behalf.

QTSPs are supervised by national authorities, audited by conformity assessment bodies and listed on the EU trusted lists. Remote signing is why a signer can create a QES in a browser without owning a card reader.

QES, digital signatures and electronic signatures

"Electronic signature" is the legal term for any signature in electronic form. "Digital signature" is the technical term for a signature created with a certificate and cryptography. Every QES is a digital signature, but not every digital signature is qualified: it only becomes a QES when it meets the advanced-signature requirements, is based on a qualified certificate and is created with a QSCD. Read more about the difference between digital and electronic signatures.

For a shorter definition, see our glossary entry on the qualified electronic signature. For the wider picture, see the different types of electronic signatures.

Is a QES legally the same as a handwritten signature?

In the EU, yes. Article 25 of eIDAS says a qualified electronic signature has the equivalent legal effect of a handwritten signature, and a QES based on a qualified certificate issued in one member state is recognized as a QES in all other member states.

A QES also gives you standardized technical evidence about who signed, which certificate was used and whether the document changed. How much weight that evidence carries in a dispute, and who has to prove what, is still decided by national procedural law. A QES does not make fraud impossible, for example if someone passes an identity check with a stolen identity.

In Switzerland, the ZertES law and the Swiss Code of Obligations treat a qualified electronic signature combined with a qualified time stamp as equivalent to a handwritten signature where the law requires written form. Swiss and EU qualified signatures follow separate legal frameworks, which is why signing tools offer them as two different options.

The United Kingdom kept a domestic version of eIDAS after Brexit. EU qualified signatures continue to be recognized as qualified in the UK, but UK qualified trust services are not automatically recognized as qualified in the EU. Check the provider's trusted-list status when a transaction must meet EU requirements.

Outside Europe the picture is different. In the United States, the ESIGN Act and UETA do not define signature levels, and an ordinary electronic signature is generally enough for most business documents. A QES can still meet the US definition of an electronic signature when the ESIGN or state UETA requirements are met, but US law gives it no separate legal tier. Read more about eIDAS signatures and ZertES signatures.

When do you need a qualified electronic signature?

Use a QES when the applicable law, a filing system or the other party specifically requires a qualified signature, or when national law lets a QES replace a handwritten signature for the document. A written-form requirement does not always allow an electronic substitute, so check the rule for the document and the country. Typical cases include:

• Contracts with a written-form requirement. Some countries require written form for certain employment terms, consumer credit agreements, guarantees or long-term leases. In Germany, for example, statutory written form can generally be replaced by electronic form unless the statute excludes it, and that electronic form requires a qualified electronic signature.
• Filings with public authorities. Some government portals and registries accept electronic documents only with a qualified signature.
• Regulated financial services. Banks and insurers may ask for a QES on account openings, loan agreements or policy changes.
• Cross-border agreements inside the EU. A QES issued in one member state must be recognized as a QES in the others, although national rules for the transaction itself still apply.
• The other party asks for it. A customer, partner or notary can require a qualified signature even when the law does not.

If none of these apply, a simple or advanced electronic signature is usually enough, and it is faster for the signer. Our guide to cross-border electronic signatures covers how requirements change between countries.

How to get a qualified electronic signature

Requirements depend on the provider and the signing method. Some people hold a reusable qualified certificate on a smart card, USB token, national eID or mobile app. In e-signature tools, a remote QES with an online identity check is more common, and the signer does not need to buy a certificate or install anything. That remote flow usually looks like this:

1. The sender chooses QES for the request. In the signing tool, the sender selects a qualified signature level for the recipient, under eIDAS or ZertES.
2. The signer opens the document. They receive the signing link by email, as with any other request.
3. The signer verifies their identity. The QTSP checks the signer's identity online, for example with an identity document and a live check, inside the signing flow.
4. The QTSP issues a qualified certificate. After a successful check, the provider issues a short-lived qualified certificate for that signer.
5. The signer signs. The signature is created with the qualified certificate and cryptographically linked to the document, so any later change can be detected.

The identity check is the extra step compared with an ordinary signature. Accepted identity documents and methods depend on the provider and the signer's country.

Certificates, time stamps and long-term validity

Some remote signing services issue short-lived certificates for a single transaction, while others use longer-lived certificates. Certificate expiry does not by itself invalidate a signature that was valid when it was created. For long-term checks, look for trusted time stamps and the certificate and revocation data needed for later validation. In Switzerland, handwritten-signature equivalence also requires a qualified time stamp.

The EU Digital Identity Wallet

The revised eIDAS framework, Regulation (EU) 2024/1183, requires every member state to offer a European Digital Identity Wallet. Wallets must let individuals create qualified electronic signatures by default and free of charge, and member states may limit the free use to non-professional purposes.

How much does a QES cost?

QES pricing works differently from ordinary e-signatures, because each qualified signature includes an identity verification by the QTSP. Providers usually charge per qualified signature or per signer on top of the subscription, often through prepaid credits. When comparing prices, check:

• whether the price is per signature, per signer or per document;
• whether credits are sold only in bundles and whether they expire;
• which plans include QES at all;
• whether failed identity checks use up a credit.

In Sign.Plus, QES is available on every plan, including Free, at $5 per recipient through QES credits bought in packs starting at 10. Purchased credits do not expire. Each credit covers one signer's identity verification and qualified signature.

What to look for in a QES provider

Several e-signature tools offer qualified signatures, but they do it in different ways. These are the questions that matter most:

• Who is the QTSP? Some vendors are a qualified trust service provider themselves, others work with one. Either works. For an EU QES, check that the provider is on an EU member state trusted list. For a Swiss QES, check that it is a recognized ZertES provider.
• Which frameworks are covered? If you sign with Swiss and EU counterparties, you may need both eIDAS and ZertES qualified signatures.
• How is identity verified? Video identification, automated document and face checks, bank-based identification or national eID schemes all exist, and availability differs by country. A smoother check means fewer abandoned signatures.
• What does the signer need? Ideally only an identity document and a phone or laptop, with no app to install and no account to create.
• What is the real cost per signer? Look past the headline price at bundle sizes, plan gating and expiry rules.
• What evidence do you get? You should receive the signed document with the qualified signature embedded, plus an audit trail of the signing events.

How to send a QES request in Sign.Plus

Sign.Plus offers qualified signatures under both eIDAS and ZertES through Swisscom Trust Services, a qualified trust service provider. QES is off by default, so it has to be allowed first.

1. Allow QES for your team. In Settings, under Signing, choose who can request qualified signatures: all members, only admins, selected members or no one.
2. Upload the document and add recipients. Start a signature request as usual and add each signer.
3. Choose the signature level. Open Signature Options and select Qualified Signature (QES) with eIDAS Identity Verification or with ZertES Identity Verification.
4. Place the fields and send. Add signature fields, write the message and send the request.
5. The signer verifies and signs. The signer is redirected to Swisscom Trust Services to verify their identity, then returns to sign. The signed PDF contains the qualified electronic signature backed by the signer's qualified certificate.

QES identity verification replaces the other recipient verification options for that signer, so you do not need to add a passcode or SMS code on top.

How to verify a qualified electronic signature

A qualified signature can be checked independently of the tool that created it. Open the signed PDF in a validator that reads the embedded certificate, and confirm that the certificate is qualified, that it was issued by a QTSP on a trusted list (for an EU QES, an EU member state trusted list; for a Swiss QES, a recognized ZertES provider) and that the document has not changed since signing. Sign.Plus has a free QES validator, and our guide on how to verify an electronic signature walks through the full check.

Limits of a qualified electronic signature

• It adds friction. The extra identity verification steps take more effort from the signer than an ordinary signature.
• Not every signer can complete it. Identity verification methods and accepted documents vary by country and provider.
• It does not decide whether the contract is valid. Authority to sign, capacity, notarization and document-specific exclusions are separate questions that a QES does not answer.
• It is usually more than you need. For most commercial documents, a simple or advanced signature with a good audit trail is enough.

The bottom line

A qualified electronic signature is the electronic equivalent of a handwritten signature in the EU and, with a qualified time stamp, in Switzerland. Use it when the law, a filing system or the other party specifically requires a qualified signature, and use simple or advanced signatures for everything else. When choosing a provider, check who the QTSP is, which frameworks are covered, how identity is verified and what each signer really costs.

Sign.Plus offers QES under eIDAS and ZertES on every plan, including Free, at $5 per recipient. Start signing with Sign.Plus.