Before you sue in Spain: attempting a MASC as a requirement to be heard

What the MASC is and why it is the door to court

A MASC (an appropriate means of dispute resolution) is any legally recognised activity that the parties to a conflict resort to in good faith to reach an out-of-court solution (art. 2 of Ley Orgánica 1/2025).

Prepare the MASC formal demand

Ley Orgánica 1/2025, of 2 January, came into force on 3 April 2025. Its Title II regulates the MASC.

In the civil and commercial jurisdiction, first attempting a MASC is a requirement for the claim to be admissible (requisito de procedibilidad, art. 5): for the court to process your demanda, you must prove in writing that you attempted a solution beforehand.

If you do not prove it, the claim is inadmissible — the court does not process it. This is the gateway: for most private-law claims you now reach court ONLY through a documented MASC attempt.

Who this applies to

• Anyone who wants to file a civil or commercial claim: against a company, a neighbour, a landlord or tenant, a debtor.
• Consumer disputes (with an insurer, a bank, a shop, a utility): the civil MASC applies, on top of the consumer routes.
• Money claims, breaches of contract, defects, damages between individuals or companies.
• It does NOT apply the same way to everything: employment and administrative matters have their own door (below).

Which methods count as a MASC

• Direct negotiation (you or your lawyer), often with a prior formal demand sent by registered letter with proof of receipt (burofax), so both content and delivery are proven.
• Mediation (Ley 5/2012): a neutral third party (mediador) helps the parties reach their own agreement.
• Conciliation before a notary, registrar or conciliator.
• A confidential binding offer: one party makes an offer that binds it; if the other rejects it and then does worse at trial, there are costs effects.
• An independent expert opinion (a neutral third party's dictamen).

How it works: effects and mechanics

• It interrupts the limitation period (prescripción) and suspends the expiry period (caducidad) from the documented request until the attempt ends (art. 7.1 of LO 1/2025; for mediation, art. 4 of Ley 5/2012): attempting it does NOT cost you the deadline to sue. Interrupted means the limitation period starts again in full once the attempt ends; suspended means the expiry period pauses and then resumes where it stopped. Beware: if within 30 calendar days of the other side receiving the request (or of the attempted delivery, if it is never received) there is no first meeting or no written answer — either one is enough —, the clock restarts or resumes (15 days in mediation: from the mediator receiving the request without trying to contact the other side, or from that side receiving the proposal — or the attempted delivery — with no first meeting or no written answer).
• The attempt counts for a claim with the same object (art. 5.1): what you sue for must be what you tried to negotiate. And the claim must be filed within one year of the other side receiving the request, or of the negotiation ending without agreement (art. 7.3); after that year the requirement is not deemed met and you must attempt again.
• It must be documented: who is claiming, what they claim, and the date. It is proven with the formal demand plus proof of delivery (burofax), or with the record or certificate of the mediation or conciliation.
• It is confidential: what is said in the MASC cannot be used later at trial.
• Costs (costas): unreasonably refusing to engage, or rejecting a binding offer and then doing worse, can make you bear the costs — the judge weighs good faith.

What is excluded from the requirement (honestly)

• Matters that are not at the free disposal of the parties, and matters excluded from mediation.
• Employment disputes have their own pre-court route — conciliation before the SMAC (a papeleta) — not the civil MASC. Dismissal or a claim for amounts and wages → SMAC first.
• Disputes with the administration (a SEPE or INSS refusal, sanctions) go through a preliminary claim (reclamación previa), an appeal for review or reversal, not the civil MASC.
• Consumer: the civil MASC applies, but there are also the complaint form (hoja de reclamaciones) and the OMIC as first steps, and consumer arbitration (arbitraje de consumo, voluntary — both parties must accept it).
• Urgent measures and certain family measures have special rules — check whether your claim is excluded.

Which door each dispute goes through

• A private civil or commercial claim (with a company, a neighbour, a landlord or tenant, a debtor) → civil MASC: negotiation with a formal demand and burofax, or mediation, or a binding offer.
• An employment dispute (with your employer) → SMAC (papeleta de conciliación) → Juzgado de lo Social.
• Benefits or the administration (SEPE, INSS) → a preliminary claim (reclamación previa) or an appeal before going to court.
• Consumer → complaint form (hoja de reclamaciones) → OMIC → consumer arbitration (voluntary) or civil MASC.
• Across all of them: the backbone of the proof is the burofax (proof of content and of delivery).

How to meet the requirement, step by step

• Identify the type of dispute (civil/commercial, employment, administrative, consumer) so you know which door is yours.
• If it is civil or commercial, choose the method: negotiation with a formal demand (burofax), mediation, conciliation, or a binding offer.
• Send the formal demand by burofax (or start the mediation): record who is claiming, what they claim, and the date — the limitation period is interrupted and the expiry period suspended.
• Keep the proof of the attempt: the burofax receipt, or the record or certificate of the mediation or conciliation.
• If there is no agreement, file the demanda with that proof of the MASC attempt attached (without it, the claim is inadmissible).

A real case: a court refused urgent measures "without a MASC" — and the appeal overturned it

Common mistakes

• Suing straight away without first attempting a MASC: in civil and commercial matters the claim is inadmissible.
• Not documenting the attempt: an email or a call with no proof does not meet the requirement — use the burofax or the record.
• Applying the civil MASC to an employment dispute (that goes through SMAC) or an administrative one (that goes through a preliminary claim).
• Believing that attempting a MASC uses up your time limit: on the contrary, it interrupts the limitation period and suspends the expiry period — but the claim must be filed within the following year (art. 7.3).
• Unreasonably rejecting a binding offer and then obtaining a worse result: you can end up bearing the costs.

Related guides

Common questions

Official sources