Signing a Rental Agreement Digitally: When Do You Need SES, AES or QES?

Handover at month-end, the new tenant still abroad, the property manager wanting the contract wrapped up before the keys change hands: few contract types benefit as much from the electronic signature as the rental agreement. The good news up front: the rental agreement itself is form-free in Switzerland [1] — it can be validly concluded with any electronic signature, provided the parties have not agreed on a specific form and the law does not require anything else for the particular declaration. The pitfalls lie elsewhere: with terminations, payment reminders, consent to tenant alterations, and the official forms. This article shows which signature level is sufficient where — including the new form requirements from the tenancy-law revision of 1 October 2025 [5].

The three signature levels in 60 seconds

In everyday practice, three levels of electronic signature are distinguished (ZertES also recognises further instruments such as regulated electronic signatures and seals [3]):

To place the AES: it can secure identity, document integrity and traceability considerably better than a simple signature. Its actual evidentiary weight, however, depends on the procedure used — identification method, certificate, audit trail and protection of the signature key are not equivalent for every AES [7].

Only the QES satisfies the statutory written form (Art. 13–15 OR [1]) — combined with a qualified timestamp [7]. It must be based on a qualified certificate from a provider recognised under ZertES [3]. According to the BAKOM list, four providers are currently recognised: DigiCert Switzerland, Swisscom, SwissSign, and the Federal Office of Information Technology (only for the federal administration) [6]. Swiss QES and regulated electronic seals can be checked free of charge via the federal validator; SES, ordinary AES from other providers, and foreign signatures cannot generally be validated by the validator [8].

Important for international constellations: Switzerland and the EU still do not mutually recognise their signatures [6]. An eIDAS QES is therefore not equivalent to a Swiss QES in Switzerland — but it can be used for form-free transactions as an electronic or advanced signature. Whether a contract additionally requires an eIDAS QES depends on the applicable law, not solely on the counterparty's domicile.

1. Form-free: SES or AES is sufficient here

The principle of form-freedom (Art. 11 OR [1]) applies broadly in tenancy law [15]. These documents can be validly signed with any signature level — for evidentiary reasons, at least an AES is recommended:

Contract conclusion and amendments

• Rental agreement for residential premises — open-ended and fixed-term (unlike Germany, there is no written-form requirement for fixed-term residential leases)
• Rental agreement for commercial premises — likewise form-free, regardless of the term
• Sub-lease agreements between tenant and sub-tenant
• Rental agreements for parking spaces, hobby rooms, storage areas
• Contract amendments and mutually agreed changes — provided the contract contains no written-form clause (see below)
• Lease-termination agreements — mutual dissolution is form-free and the safe digital way to end a tenancy early (caution with the family dwelling: obtain and document the consent of both spouses)

Ongoing tenancy

• Handover and return protocols
• Deposit agreements (Art. 257e OR [1])
• Consent to pets and to subletting (note: renovations and structural changes by the tenant, by contrast, require written consent — see Section 2)
• Notices of defects by the tenant — form-free, but written or signed form recommended for evidentiary reasons
• Voluntary rent reductions by the landlord — unilateral changes exclusively in the tenant's favour need no official form. Two distinctions: the statutory request for reduction by the tenant must be made in writing (Art. 270a(2) OR — see Section 2), and if a reduction is combined with a change to the tenant's detriment (e.g. new ancillary-cost items), the overall package is again subject to the form requirement under Art. 269d OR [1]
• Ancillary-cost statements and payment arrangements
• Management powers of attorney and house rules

Caution — written-form clause: If the rental agreement contains the clause "amendments require written form", it is presumed that the parties do not wish to be bound before the form is met (Art. 16(1) OR [1]). If the clause says nothing more specific, the requirements of the statutory written form apply (Art. 16(2) OR [1]) — amendments then require a handwritten signature or a QES [15]. Anyone wanting to work digitally should word the clause accordingly, for example:

"Amendments and additions to this contract may, insofar as no mandatory statutory form requirement applies, also be agreed with an advanced electronic signature (AES)."

The reservation is important: where the law requires written form, the parties cannot lower it by a contract clause — there, QES or a handwritten signature always applies.

2. Statutory written form: QES or a handwritten signature is required

What matters is not whether a declaration is unilateral or bilateral, but solely whether the law or the contract requires written form for it. In tenancy law these are in particular:

A tenant's termination given by email or with a mere AES is void [15] — a classic among the expensive formal defects, because the tenancy then simply continues. With a QES, by contrast, a digital tenant termination is legally valid.

Distinction — early return: The announcement of an early return under Art. 264 OR [1] and the presentation of a reasonable replacement tenant are in principle form-free, but should be documented for evidentiary reasons [11]. If an ordinary termination is also declared, the written form of Art. 266l OR applies to that.

Three practical notes on terminations and form-bound declarations:

• Delivery: Signing validly is one half — proving receipt is the other. Anyone terminating electronically needs the other side's consent to electronic delivery and a robust proof of delivery; in case of doubt, registered mail remains the safest channel [14].
• Multiple tenants: In a joint tenancy, the termination should be signed by all tenants or be based on a demonstrable power of attorney — electronically this means: QES of all parties involved, or a validly granted power of attorney.
• Signing authority: A QES proves which natural person signed — not automatically that this person was authorised to sign for the management or the ownership. Signing authorities should therefore be cleanly documented (commercial register, power of attorney).

3. Official form: physical delivery as the legally secure standard

For certain landlord declarations, the law requires qualified written form in the shape of an official form approved by the canton [9]:

• Termination by the landlord (residential and commercial premises): the official form is mandatory (Art. 266l(2) OR [1]), otherwise void. For the family dwelling, the termination must be delivered to the tenant and the spouse separately (Art. 266n OR [1]).
• Rent increases and other unilateral contract changes: official form with justification, at least 10 days before the start of the notice period (Art. 269d OR [1]). Without the form: void [10].
• Notification of the initial rent: according to the annually updated register of the Federal Housing Office, in 2026 a form requirement applies in the cantons BS, BE, FR, GE, LU, ZG and ZH, and partly in NE and VD [4]. The requirement is tied to the vacancy rate and can change annually — the current BWO register is decisive. Since 1 October 2025, the form must additionally state the reference interest rate and the Swiss consumer price index on which the previous rent was based (Art. 19 VMWG [2]).

For these form-based notifications, physical delivery currently remains the most legally secure standard. Under federal law, electronic form is not fundamentally excluded — whether a fully electronic process is possible depends on the canton-approved form, the permissible signature, and robust proof of delivery.

Two easements from the revision of 1 October 2025 [12] [13]:

1. Facsimile signature suffices on the form: For rent increases and other unilateral contract changes, a mechanically reproduced signature on the prescribed form is now sufficient (Art. 269d(4) OR [1]). This significantly relieves managements in mass mailings — but does not apply to terminations [12].
2. Stepped rent without a form: The individual rent steps no longer have to be notified via an official form, but only in writing (Art. 269d(5) OR [1]) — at the earliest four months before the increase takes effect (Art. 19a VMWG [2]) [5]. Written form means: a handwritten signature or QES. This makes the stepped-rent notification fully digital for the first time.

Legally valid is not the same as provable

Two questions are often mixed up in everyday practice but belong apart:

• Effectiveness (the legal position): Is the declaration valid at all in this form? Only the law answers that — form-free, written form, or official form. A form-free rental agreement is just as valid with an SES as with a QES.
• Provability (practice): Can I demonstrate in a dispute who signed what and when — and that the declaration was received? Here the levels part ways: an SES is easily contestable. AES and QES attribute the signature to an identified person and secure document integrity (Art. 2 ZertES [3]); the QES offers the strongest position because it is equivalent to a handwritten signature.

What is legally required is not up for debate. Where form-freedom applies, the choice of level is a risk assessment — the higher the probability and value of a dispute (protection against termination, deposit, defects), the higher the level should be.

Overview: which signature for which document?

Legend: ✅ = legally valid in this form · ❌ = does not satisfy the required form · (❌) = electronically not currently the legally secure route (official form / physical delivery decisive) · – = not applicable

*without a written-form clause in the contract

How to read the table: ✅/❌ reflects the legal position (valid or not), the last column the practical residual risk if the lowest permitted level is chosen.

Recommendations for practice

1. AES as the standard for contract conclusion (practice recommendation). For rental agreements, protocols and amendments, the AES offers the best ratio of legal certainty, evidentiary value and user-friendliness — the tenant needs no prior identification at QES level.
2. QES wherever statutory or contractual written form applies (legally required). In tenancy law these are in particular tenant terminations, reminders under Art. 257d OR, consent to tenant alterations under Art. 260a OR, and stepped-rent notifications. Anyone wanting to work digitally here cannot avoid the QES.
3. Control the signature level per document. A tenancy file rarely consists of a single document: contract (AES), handover protocol (SES/AES), later perhaps a reminder (QES). A signature platform should enforce the required level per document in the workflow, rather than applying one level to everything across the board.
4. Electronically signed stays electronic. A digitally signed rental agreement is archived electronically — the printout is only a copy without a verifiable signature. Conversely, for handwritten contracts: the scan does not replace the original in evidentiary terms — the paper original should therefore be retained.
5. Word written-form clauses deliberately. Anyone who states in their rental-agreement templates that — insofar as no mandatory statutory form requirement applies — AES also suffices for amendments spares themselves the later QES obligation on every addendum (Art. 14(2bis) OR permits deviating agreements [1]).
6. Don't forget delivery. The signature does not replace proof of receipt. For terminations and form notifications: registered mail or an equivalent, provable delivery channel [10] [14].

FAQ

Can I conclude a rental agreement in Switzerland by email or with a simple e-signature? Yes. The rental agreement is form-free and would in theory even be valid orally (Art. 11 OR [1]). For evidentiary reasons, at least an AES is recommended.

Does that also apply to fixed-term rental agreements? Yes. Unlike Germany, for example, Swiss law has no written-form requirement for fixed-term residential or commercial leases.

Can the tenant terminate their flat digitally? Yes — but only with a QES. SES and AES do not satisfy the written form of Art. 266l(1) OR [1]; the termination would be void. In addition, delivery to the landlord must be provable, and with multiple tenants all should sign or there must be a power of attorney.

Can the landlord terminate digitally? A landlord's termination requires the official, canton-approved form (Art. 266l(2) OR [1]) and, for family dwellings, separate delivery to both spouses (Art. 266n OR). Physical delivery by registered mail is currently the most legally secure standard here.

What changed on 1 October 2025? Three things [5] [12]: facsimile signatures are sufficient on the form for rent increases (Art. 269d(4) OR), stepped-rent increases now only require written form instead of the official form (Art. 269d(5) OR, at the earliest 4 months in advance per Art. 19a VMWG), and the initial-rent form must state the reference interest rate and CPI of the previous rent (Art. 19 VMWG [2]).

What applies if the rental agreement contains a written-form clause? Then amendments and terminations require the agreed form (Art. 16 OR [1]) — in case of doubt, a handwritten signature or QES. The clause can, however, be worded so that AES suffices, insofar as no mandatory statutory form requirement applies.

Is a foreign e-signature (e.g. an eIDAS QES) treated the same as a Swiss QES in Switzerland? No. In the absence of mutual recognition between Switzerland and the EU, an eIDAS QES does not satisfy the Swiss written form [6]; for that you need the QES of a provider recognised under ZertES [3]. For form-free transactions, however, an eIDAS QES can be used as an electronic or advanced signature. Whether a contract additionally requires an eIDAS QES depends on the applicable law.

How do I retain digitally signed rental agreements? In the signed original PDF, electronically. Only this keeps the signature verifiable long-term — ideally with a long-term format (PAdES-LTA) and a qualified timestamp. Swiss QES can be checked via the federal validator [8].

Conclusion

Swiss tenancy law is more digital-friendly than many people think: the entire contract conclusion — from the rental agreement through the handover protocol to the termination agreement — works fully electronically with SES or AES. The QES comes into play wherever the law or the contract requires written form: for the tenant's termination, for reminders, for consent to tenant alterations, and, newly, for stepped-rent notifications. For the form-based landlord declarations, physical delivery currently remains the most legally secure standard.

The decisive factor is that the signature solution enforces the right level per document. With actaSIGN, property managements and landlords define the required signature level for every document in the workflow, from SES to QES; the qualified signatures are issued via Swisscom, a provider recognised under ZertES.

Further Reading

• SES, AES, QES: the three signature levels explained
• Qualified electronic signature (QES): the guide
• HR documents in Switzerland: which signature for which document?
• Electronic signature in Switzerland: legal framework and practice
• Signature solution for property management
• Request a demo

Sources

1. Code of Obligations (OR, SR 220) — in particular Art. 11, 13–16, 253 et seq., 257d, 257e, 257f, 259g, 260a, 263, 264, 266l–266n, 269d and 270a
2. Ordinance on the Renting and Leasing of Residential and Commercial Premises (VMWG, SR 221.213.11) — in particular Art. 19 and 19a
3. Federal Act on Electronic Signatures (ZertES, SR 943.03)
4. Federal Housing Office (BWO) — 2026 register: form requirement for notifying the initial rent
5. Federal Council media release of 21 March 2025 on bringing the tenancy-law amendments into force on 1 October 2025
6. BAKOM — Electronic signature, list of recognised providers
7. Federal Office of Information Technology (BIT) — E-signature FAQ
8. Federal signature validator — scope of functions per BIT
9. Canton of Zurich — Tenancy forms (official forms for termination, rent increase, initial rent)
10. Courts of the Canton of Zurich — Rent increase: form, deadlines, nullity
11. Courts of the Canton of Zurich — Early return of the rental object (Art. 264 OR)
12. Häusermann + Partner — Changes in tenancy law: watch out, new form requirements! (2025)
13. legalis — The tenancy-law changes entering into force on 1 October 2025
14. Zeitschrift Wohnen — Possible uses of the electronic signature in tenancy law
15. KMU-Magazin — Electronic signatures and digital contracts (2026)

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This article reflects the legal status as of August 2026 and does not replace legal advice in individual cases — precisely in tenancy law, formal defects in terminations, reminders and form notifications lead to the nullity of the declaration. The research was carried out with the support of artificial intelligence; the legal bases cited were verified against the primary sources (Fedlex, BWO, BAKOM, cantonal form offices). The article was reviewed and edited by a natural person before publication.