Electronic signatures in Switzerland: which level do you actually need?
There are three signature levels, and most of the writing about them comes from vendors of the most expensive one. The question is not which level is most secure, but which one the law requires for your document — and for the large majority of business agreements it requires none.
Short answers
- How many levels are there?
- Three: simple (SES), advanced (AES) and qualified (QES). Only the QES is treated as legally equivalent to a handwritten signature.
- What applies to a quote?
- Quotes, order confirmations, and service or work contracts are form-free (Art. 11 CO). They are valid even unsigned — a simple electronic signature is sufficient and substantially improves your evidentiary position.
- When is a QES mandatory?
- Whenever the law prescribes written form — for example assignment of a claim, or a non-compete clause. There, only the QES is equivalent to a handwritten signature.
- Is a simple signature usable in court?
- Yes. Civil procedure applies free assessment of evidence: a court may consider any evidence. The difference is not admissibility but how much work the proof takes.
- Does an EU signature work in Switzerland?
- Not automatically. A signature qualified under eIDAS is not by itself a QES under ZertES — that requires a provider recognised in Switzerland. For form-bound contracts with a Swiss nexus this matters.
The starting point is freedom of form
Art. 11 CO states that contracts require a particular form for their validity only where the law prescribes one. The default in commerce is therefore freedom of form — a contract is concluded by matching declarations of intent, spoken, by email, or by clicking.
That leads somewhere vendor literature rarely states plainly: for the majority of documents an SME asks people to sign, the choice of signature level is not a validity question. It is an evidence question. And evidence questions are answered by weighing effort against risk, not by reaching for the technical maximum.
The three levels
ZertES distinguishes three qualities. What separates them is how rigorously the signer’s identity is verified and how tightly the signature is bound to the document.
- SES — simple electronic signature. Electronic data attributed to a person, with no certificate from a recognised provider. Its evidentiary weight depends on the surrounding documentation: identity evidence, timestamp, log.
- AES — advanced electronic signature. Uniquely attributed to the signer, capable of identifying them, and any subsequent change to the document is detectable.
- QES — qualified electronic signature. As AES, plus a qualified certificate from a provider recognised under ZertES and a secure signature-creation device. Only this level is equivalent to a handwritten signature.
Evidentiary weight is not the same as formal validity
Two questions get conflated. First: was the contract validly concluded at all? Second: can I prove, in a dispute, that the other side agreed?
For form-free contracts the first question is not in issue — the contract holds. Only the second matters. And there the signature level alone does not decide; what is documented alongside it does. Who approved which version of the document, when, from which verified address, and can it be shown the document is unchanged since?
A simple signature with complete logging can end up in a stronger position than a scanned handwritten signature on a PDF whose provenance nobody can reconstruct.
Where written form is prescribed
Where the law requires written form, only the QES will do. The table below covers the cases that actually arise in SME practice — it is not the complete list.
A third category is often forgotten: for some transactions even a QES is not enough. A property purchase requires public notarisation, and no electronic route bypasses the notary.
Decision table: which level for which document
| Document | Form requirement | Signature needed |
|---|---|---|
| Quote, order confirmation | none (Art. 11 CO) | SES is sufficient |
| Work and service contracts | none | SES is sufficient |
| Non-disclosure agreement | none | SES is sufficient |
| Standard employment contract | none | SES is sufficient |
| Assignment of a claim | written form (Art. 165 CO) | QES |
| Non-compete clause in employment | written form (Art. 340 CO) | QES |
| Surety | written form; public notarisation for natural persons above CHF 2,000 | QES or notary |
| Property purchase | public notarisation | no electronic signature possible |
Where athemi sits — and where it does not
athemi works with the simple electronic signature and concentrates on what gives it evidentiary weight: traceable identity, timestamping, and a document whose integrity can be demonstrated. For quotes, order confirmations and service contracts — the daily reality for most SMEs — that is the appropriate level.
- The signer’s identity is verified before approval.
- Timestamp and complete log of every view and every approval.
- The approved document is protected against later modification and stays retrievable in that exact version.
- No QES: for contracts under a statutory written-form requirement you need a provider recognised under ZertES. athemi does not replace one and does not claim to.
Frequently asked
Is an emailed confirmation of a quote enough?
Legally yes — the quote is form-free, and an emailed acceptance concludes the contract. In practice it is the weakest option: the acceptance lives in a mailbox, often does not clearly reference a specific version, and whether the attached PDF has changed since is nearly impossible to show later.
Is a scanned signature an electronic signature?
No. An image of a signature is an image. It falls under none of the three ZertES levels and can be copied at will. It may serve as an indication, nothing more.
What if the other side disputes the signature?
Then what is documented decides. With a QES, the disputing party effectively carries the burden of showing otherwise. With a simple signature you must evidence the process — with identity verification, timestamp and log that is regularly achievable, but it is your task.
Do international customers require a QES?
That depends on the applicable law and the document, not on where the counterparty lives. The asymmetry is what matters: a signature qualified under eIDAS is not automatically a QES under ZertES. For form-bound contracts with a Swiss nexus, settle this in advance.
Related guides
-
The Swiss 10-year retention obligation, accurately
Ten years from the end of the financial year. What Art. 958f CO and the GeBüV actually require — and why the storage location is not prescribed.
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The revised Swiss data protection act, read practically
In force since 1.9.2023. Which duties genuinely apply to an SME, why the fine targets the individual rather than the company, and what it means for documents sent by email.
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Getting a quote signed off, digitally
How long does your quote bind you? Does it need a signature at all? Binding periods under the CO, the cost-estimate distinction, and documenting approval digitally.
Sources
This page frames the legal position in general terms and is not legal advice. Whether a particular contract is form-bound depends on the specific case — clarify before signing, not after.
Last reviewed: 2026-07-25