Yes. Spanish law does not require a burofax (a certified postal communication with proof of content and delivery) or any other channel. It asks for a document proving the debtor received your invitation to negotiate, on what date, and could access its full content (art. 10.2, Organic Law 1/2025). A certified email that records those three facts does the job, provided it goes to an address the debtor uses and offers a negotiation, not just a demand for payment.
Work out your deadlines: with the date of receipt, our MASC deadline calculator tells you when the attempt ends and the last day to file.
What the law has required since 3 April 2025
Organic Law 1/2025 on the efficiency of the Public Justice Service (Ley Orgánica 1/2025 de medidas en materia de eficiencia del Servicio Público de Justicia) came into force on 3 April 2025. It applies to proceedings started after that date. Its article 5.1 turns a prior attempt at an "appropriate means of dispute resolution" (medio adecuado de solución de controversias, MASC) into a precondition for suing (requisito de procedibilidad). Without that attempt, the court will not admit your claim.
There is a second condition. There must be "una identidad entre el objeto de la negociación y el objeto del litigio" (the same subject in the negotiation and in the lawsuit). In plain terms: the debt you tried to negotiate has to be the same debt you later claim in court.
The requirement covers almost every civil case, and the domestic payment order procedure (proceso monitorio), the simplified court route for recovering a debt, is not among the exceptions. The exceptions in articles 5.2 and 5.3 are specific: bills of exchange claims (juicio cambiario), the protection of fundamental rights, enforcement claims, interim measures sought before the claim and the European payment order, among others. An ordinary claim for a debt is not on the list. For a community of owners (comunidad de propietarios) claiming unpaid fees through a monitorio, the courts do not agree: we explain it in MASC for communities of owners.
What counts as a MASC? Article 2 defines it broadly: "cualquier tipo de actividad negociadora" (any kind of negotiating activity) that the parties turn to in good faith. Mediation counts. So do conciliation and a confidential binding offer. But direct negotiation between the parties, or between their lawyers, counts too. For a simple claim the usual route is the last one: a written invitation to negotiate, with a proposal attached.
What you need to be able to prove
Article 10 requires the negotiation to be "recogida documentalmente" (recorded in writing). If there is no document signed by both parties, it is enough to have "cualquier documento que pruebe que la otra parte ha recibido la solicitud o invitación para negociar o, en su caso, la propuesta, en qué fecha, y que ha podido acceder a su contenido íntegro" (any document proving that the other party received the request or invitation to negotiate or, where relevant, the proposal, on what date, and that they were able to access its full content).
That is three facts. Keep them clear in your head, because they are what a court will look at:
- Receipt. Sending is not enough. You have to prove it arrived.
- Date. The deadlines hang on it. The negotiation counts as attempted and failed if thirty calendar days pass from receipt with no meeting and no written reply (art. 10.4). From then, you have one year to file your claim (art. 7.3).
- Access to the full content. The debtor must have been able to read the whole proposal, not just a subject line or a notification.
The law does not name email or burofax. It mentions a channel only once, in article 7.1, when it deals with interrupting the limitation period: communication at the person's home or workplace, "o bien a través del medio de comunicación electrónico empleado por las partes en sus relaciones previas" (or through the electronic means of communication the parties used in their previous dealings).
What do the courts say? They accept email, with nuances
Because the law does not fix the channel, the courts have been setting out for themselves what works. So far, email appears on every list:
- The Barcelona Provincial Court (Audiencia Provincial, the appeal court for each province), in its presiding judges' agreement of 31 October 2025, accepts "correo postal con acuse de recibo, burofax, buro-mail o email, WhatsApp, así como cualesquiera otros medios que permitan dejar constancia del envío y de su recepción" (post with acknowledgement of receipt, burofax, buro-mail or email, WhatsApp, and any other means that leave a record of sending and receipt). According to the published summaries of its orders (autos) 285/2026 and 301/2026, Section 5 of the Alicante Provincial Court uses the same list.
- The Alicante courts of first instance accept email if it was agreed as the usual channel or has been used "de manera reiterada, con un mínimo de tres intercambios en los seis meses anteriores" (repeatedly, with at least three exchanges in the previous six months). They also presume the requirement is met when the attempt is documented by "burofax, correo electrónico o SMS, salvo que el requerido demuestre lo contrario" (burofax, email or SMS, unless the other party proves otherwise).
- The Valencia Provincial Court, in its criteria of 15 June 2026, treats as valid "la comunicación por e-mail designado en contrato o el que sea habitual en esas relaciones" (communication to the email address named in the contract, or the one normally used in that relationship).
The same idea keeps coming back: email counts if it is a real channel between the parties. Writing to an address the debtor has never used with you is the easiest thing for them to challenge.
What a certified email adds over an ordinary one
An ordinary email proves, at most, that you sent it. It does not prove that it arrived, or when, or that anyone opened the document. A certified email is built precisely to cover the three facts in article 10.2:
- Delivery, with date and time, to the recipient's mail server.
- Opening of the message and download of the document from its link, also with date, time and IP address. Opening is only indicative, because some email programs hide it or fake it. The download is the strong proof.
- Integrity of the content: a digital fingerprint (SHA-256) that lets you check that the document you file in court is exactly the one you sent.
With that, the certificate answers all three questions. It arrived, on this date, and the full document was downloaded from the link sent to that address. What it cannot show is who was sitting at the screen. That is why it matters so much that the address is the one the debtor really uses.
What a certified email is not
Precision matters here, because this is where people exaggerate most. The EU eIDAS Regulation distinguishes two kinds of electronic registered delivery service:
- Qualified services, run by trust service providers on the official list. Only they enjoy the legal presumption in article 43.2 of eIDAS (integrity of the data, sender, recipient and exact date and time) and the one in article 326.4 of the Civil Procedure Act (Ley de Enjuiciamiento Civil, LEC).
- Non-qualified services. Article 43.1 guarantees they will not be denied value as evidence "por el mero hecho" (solely because) they are electronic or not qualified. If the other side challenges them, the judge weighs them freely, together with the rest of the evidence (art. 326.3 LEC).
The service we build is the second kind. It is valid evidence, the kind the criteria above accept, but it carries no automatic presumption. If the debtor is going to fight every detail, or has never used email with you, combine channels: certified email plus a burofax to the address they designated.
What we learned sending certified communications
We work with an administrador de fincas (property/community manager) in the province of Alicante who sends owners' meeting notices by certified email. The first real campaign taught us something that applies to any claim. Of the first fifty addresses, three bounced, because the list of owners' email addresses was out of date.
A bounce is not a system failure. It is information. It tells you in time that this channel does not work for that debtor and that you need another one, before thirty days go by counting from a receipt that never happened.
So before you use email for a MASC, check that the address is the one the debtor uses with you. And keep the certificate for every send: it is the document you will have to file with your claim.
Before you send: a checklist
- Define the subject. Article 7.1 asks for a request "en la que se defina adecuadamente el objeto de la negociación" (that properly defines the subject of the negotiation): which debt, for what period, what amount.
- Propose something concrete. A payment plan, a deadline, a partial write-off. A demand for payment with no room to move looks very little like a negotiation, and some courts have already said so.
- Use the usual channel. The address the debtor has used with you, ideally agreed in writing.
- Set the deadline. Say that if there is no reply within thirty calendar days, you will treat the attempt as closed.
- Keep the proof. The certificate with delivery, opening, download and the document's fingerprint. If you have no way of contacting the debtor, the law provides for a formal signed statement (declaración responsable) (art. 264.4 LEC).
- Describe it in your claim. Article 399.3 LEC requires the claim to describe the negotiation you attempted.
Sources
- Organic Law 1/2025, of 2 January, on measures for the efficiency of the Public Justice Service (Ley Orgánica 1/2025), arts. 2, 5, 7 and 10.
- Law 1/2000, Civil Procedure Act (Ley de Enjuiciamiento Civil), arts. 264, 326 and 399.
- Regulation (EU) 910/2014 (eIDAS), art. 43.
- Barcelona Provincial Court, Section 13, order 375/2026, which sets out the presiding judges' agreement of 31 October 2025.
- Criteria of the Alicante courts of first instance on LO 1/2025.
- Unified civil criteria of the Valencia Provincial Court, 15 June 2026.
This article explains the law and published court criteria as of the update date. It is not a substitute for advice from a lawyer on a specific case.