Are electronic means valid for complying with the MASC requirement?
Organic Law 1/2025 and the new procedural admissibility requirement in civil and commercial matters
The entry into force of Organic Law 1/2025 of 2 January on measures to improve the efficiency of the Public Justice Service (LO 1/2025) has brought about a substantial change in access to civil and commercial jurisdiction.
As of 3 April 2025, the filing of a claim generally requires the prior use of an appropriate means of dispute resolution (medio adecuado de solución de controversias – MASC) as a procedural admissibility requirement.
This new framework has raised significant practical questions in litigation practice: which means are valid? what level of formality is required? how must the attempt at negotiation be evidenced? can email or WhatsApp be used?
The Provincial Courts (Audiencias Provinciales) have begun to provide answers. In this article, we analyse the most relevant judicial criteria, with particular attention to the rulings issued by the Provincial Courts of Cádiz, Barcelona and Navarra.
MASC as a mandatory step before bringing proceedings
LO 1/2025 defines MASC as a prior negotiating activity aimed at reaching an out-of-court settlement, either directly between the parties or with the involvement of a neutral third party.
Article 5 establishes the prior attempt at negotiation as a procedural admissibility requirement, while Article 17 specifically regulates the confidential binding offer, which has become one of the most commonly used instruments in practice.
From a procedural standpoint, the Law imposes:
- An obligation to documentary evidence the attempt at negotiation.
- Inadmissibility of the claim in the event of non-compliance.
- Amendments to Articles 264.4, 399.3 and 403 of the Civil Procedure Act (LEC), strengthening judicial scrutiny of this requirement.
However, the Law does not impose a specific means for conducting the negotiating activity, which has required the courts to interpret its scope.
Is email a valid means of complying with the MASC requirement?
Order of the Provincial Court of Cádiz, 14 October 2025
The Provincial Court of Cádiz analysed the validity of email as a means of sending a negotiation proposal or a confidential binding offer.
The Court held that the use of email is fully admissible where:
- There is an express contractual provision authorising it as a means of communication.
- Or there is a tacit agreement arising from its ordinary and repeated use in the parties’ dealings.
The Court equated the designation of an email address with that of a postal address, imposing on the party who provides it a duty to monitor incoming communications.
It also rejected excessively formalistic interpretations requiring acknowledgements of receipt that are beyond the sender’s control, stressing that what matters is achieving reasonable proof of dispatch and receipt, in line with the general doctrine on receptive communications.
WhatsApp and other electronic means as prior negotiating activity for MASC purposes
Order of the Provincial Court of Barcelona, 19 December 2025
The Provincial Court of Barcelona went a step further and expressly listed the valid means of communication for issuing an invitation to negotiate or a confidential binding offer.
These include:
- Postal mail with acknowledgement of receipt
- Burofax
- Buro-mail or email
- Instant messaging (WhatsApp)
- Any other means that allows proof of dispatch and receipt
The Court emphasised that, for admissibility purposes, it is not necessary to provide the content of the offer, it being sufficient to justify that it was sent and received and that the statutory one-month period elapsed without express acceptance.
This ruling consolidates a technology-aware interpretation adapted to real commercial practice, particularly relevant in business and commercial relationships.
Confidentiality of the binding offer: evidential limits under LO 1/2025
Order of the Provincial Court of Navarra, 13 October 2025
The Provincial Court of Navarra addressed one of the most sensitive issues arising from LO 1/2025: the relationship between the confidentiality of the binding offer and the documentation required to comply with the admissibility requirement.
The Court recalled that inadmissibility of a claim directly affects the fundamental right of access to justice, and therefore a restrictive interpretation in line with the pro actione principle must apply.
Accordingly, it concluded that:
- Submission of the full content of the offer cannot be required.
- It is not necessary to include waivers, write-offs or patrimonial sacrifices.
- It is sufficient to identify the subject matter of the dispute, the parties involved, and to evidence dispatch and receipt.
Confidentiality exists precisely to prevent the content of the offer from conditioning or prejudicing the subsequent procedural position of the party making it.
Consolidated judicial criteria on mandatory MASC
A combined analysis of these decisions reveals a clear judicial trend:
- Purposive and anti-formalist interpretation of the admissibility requirement.
- Acceptance of ordinary electronic means used in legal and commercial dealings.
- Decisive relevance of prior use between the parties.
- Central importance of proof of dispatch and receipt, not of successful negotiation.
- Rejection of evidential requirements dependent on the recipient’s will.
In short, the courts are preventing MASC from becoming an unjustified formal barrier to effective judicial protection.
How to properly evidence MASC before filing a claim
From a procedural practice perspective, it is essential to integrate MASC from the outset of the litigation strategy. To that end, we recommend:
- Using traceable means (certified email, WhatsApp with evidential support, burofax).
- Verifying that the channel used coincides with that contractually agreed or previously used.
- Retaining proof of dispatch, receipt and date.
- Respecting the one-month waiting period before issuing proceedings.
- Attaching to the claim only the supporting evidence, without disclosing the content of the offer.
- Describing the negotiation process in accordance with Articles 264.4 and 399.3 LEC.
Conclusion: how to avoid inadmissibility for failure to comply with LO 1/2025
LO 1/2025 has introduced a structural change in access to civil and commercial jurisdiction.
Lower court case law is laying the foundations for a coherent, flexible application compatible with the right of defence, admitting electronic means and rejecting unnecessary formalism.
The key is not to avoid MASC, but to document it correctly.
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