A MASC (medio adecuado de solución de controversias) is any negotiation the parties to a dispute enter in good faith to settle it out of court, alone or with a neutral third party. Since 3 April 2025, a Spanish court will not admit almost any civil claim without a documented attempt at one.
In practice
To claim a simple debt, the MASC is usually a letter or email inviting the other side to negotiate, with a concrete proposal: instalments, a deadline, a date to talk. The law also accepts mediation, conciliation, the opinion of an independent expert, a confidential binding offer and collaborative law.
What decides whether the attempt counts is the proof. You must be able to show the other party received the invitation, on what date, and could read all of it. That is why the channel matters: a delivered burofax meets the test, and so does an email sent to an address the debtor really uses with you. We explain this in MASC by certified email.
Deadlines run from receipt, not from sending. If thirty calendar days pass with no meeting and no written reply, the attempt ends without agreement, and from then you have one year to file. Our MASC deadline calculator does that count from the date of receipt. A lawyer is only compulsory when the MASC is a binding offer, and not even then if the matter is worth €2,000 or less.
For a community of owners' fees claim through the payment order procedure (proceso monitorio), the courts disagree. The Provincial Courts of Alicante, Valencia and Málaga require a MASC; those of Asturias and Pontevedra treat the payment demand under the Horizontal Property Act as enough. The Supreme Court has not settled it. The steps for a community are in claiming community fees under the MASC rule.
What the law says
- Article 2 of Organic Law 1/2025. Defines the MASC as "cualquier tipo de actividad negociadora" (any kind of negotiating activity) the parties enter "de buena fe" (in good faith).
- Article 5.1. Makes it a precondition for the claim and requires "una identidad entre el objeto de la negociación y el objeto del litigio" (the same subject in the negotiation and in the lawsuit).
- Articles 5.2 and 5.3. Exceptions include bills of exchange claims, enforcement claims, interim measures before a claim and the European payment order. The domestic payment order is not on the list.
- Article 6.2. A lawyer is compulsory only for a binding offer above €2,000.
- Article 7. The request must "adecuadamente" (properly) define the subject of the negotiation (7.1); one year to file (7.3).
- Article 10. How the attempt is proved (10.2) and when it ends without agreement (10.4).
- Articles 264.4 and 399.3 of the Civil Procedure Act. The proof goes with the claim, which must describe the negotiation.
Common mistakes
- A payment demand with no proposal. The Alicante Provincial Court: "La finalidad del MASC no se satisface con un mero requerimiento unilateral de pago" (the purpose of the MASC is not met by a mere unilateral demand for payment).
- Negotiating one thing and suing for another. The subjects must match.
- Counting from the date you sent it. The thirty days start on receipt.