Wenger Plattner obtains leading decision on arbitration agreements concluded via WhatsApp

The successful setting-aside proceedings were brought against an award issued by a sole arbitrator, which had been made in response to an arbitration claim brought by an art dealer against a private individual represented by Wenger Plattner. The arbitration proceedings were initiated in accordance with the Swiss Rules of International Arbitration of the Swiss Arbitration Centre. The respondent contested the arbitral tribunal’s jurisdiction. However, the sole arbitrator dismissed the objections raised against her jurisdiction and ordered the respondent to make various payments.

The sole arbitrator based her jurisdiction on arbitration clauses contained in summary form under ‘Key Terms’ in PDF invoices sent via WhatsApp, as well as in the attached general terms and conditions. According to the sole arbitrator, the arbitration clauses contained in the invoices and in the attached general terms and conditions constituted offers to subsequently amend sales contracts already concluded, which the respondent had accepted via WhatsApp.

In response, the respondent, represented by Wenger Plattner, initiated setting-aside proceedings before the Federal Supreme Court. In its ruling, the Federal Supreme Court first noted that waiving the right to bring proceedings before a state court severely restricts the avenues of appeal for the parties. According to its jurisprudence, such an intention to waive this right cannot be assumed lightly and, consequently, in cases of doubt, a restrictive interpretation is required.

It is true that, in principle, the requirement of an arbitration clause being in text form can be fulfilled through the exchange of WhatsApp messages. However, when interpreting whether these messages express, in good faith, a clear intention to exclude state jurisdiction in favour of an arbitral tribunal, one must take into account the nature of text messaging: WhatsApp is designed for informal communication, and messages are usually composed and read on a mobile phone. Therefore, the Federal Supreme Court found that, in principle, a multi-page PDF document cannot be expected to be read in every detail.

No such clear intention to waive state court jurisdiction emerged from the WhatsApp exchange under consideration. The Federal Supreme Court noted that there was already a lack of sufficient reference to the general terms and conditions and the arbitration clause contained therein. The entire WhatsApp correspondence made no mention whatsoever of the ‘Key Terms’ or the general terms and conditions, let alone the arbitration clause contained therein. According to general commercial practice, an invoice is a document serving as a request for payment and not as a basis for establishing or amending contractual terms.

In the absence of a valid arbitration agreement, the sole arbitrator wrongly declared herself competent to hear the dispute. Accordingly, the Federal Supreme Court upheld the appeal, set aside the contested arbitral award and found that the sole arbitrator lacked jurisdiction.

Federal Supreme Court 4A_237/2026