Verified on 30 October 2026. Should any information have changed, notify me and I shall update it with the date of the amendment.
You have delivered a commission and the client has not paid. There is a sequence of steps, from least to most formal, and they should be followed in order. This guide explains these steps, the evidence to retain, when the late payment legislation applies, and which interest may be claimed. This is intended for adults; if you are a minor, your legal representatives must make the claim. This is information, not legal advice: before initiating a claim, consult a lawyer if the amount is significant.
Before claiming: evidence to retain
To make a claim, you must demonstrate the commission, the delivery, and the debt. This is my personal list:
- The accepted quote, including the price, deadlines, and authorised usage.
- The messages and emails in which the work is commissioned, approved, and delivered.
- The delivered files, including the date.
- The invoice, if applicable. How to issue one is explained in First illustration commission.
- Proof of partial payments or the deposit.
- The reminders you have sent.
Keep everything in a secure location and retain a copy. If you do not have a written quote or an invoice, the claim is more difficult.
Step 1: amicable reminder
Non-payment may be an oversight. A cordial message, including the delivery date, the amount, and a deadline, is the least costly step. My suggested template:
Hello [name]. I am writing to you because, as agreed on [date], the illustration was delivered on [date] and the payment of [amount] was due on [date]. It has not yet appeared in my account. Could you please confirm when you will make the payment? I have attached the accepted quote and the invoice. Thank you.
Step 2: formal notice of default
If the reminder is ineffective, the next step is a formal notice that provides evidence of your claim and the date. A certified letter with proof of content is the standard method. My suggested template:
[Details of the claimant]. To [details of the debtor]. I am claiming payment of [amount] for [concept], a commission accepted on [date], delivered on [date], invoice number [number] dated [date], which was due on [date]. I grant you [deadline] for full payment via [payment method]. If this does not occur, I shall initiate legal proceedings for the principal, interest, and any applicable costs. Attached are copies of the accepted quote and the invoice.
The sources I have reviewed do not address the effect of a formal notice on interest. To determine from when it accrues, consult a lawyer.
Default interest
There are two regimes, depending on the nature of the client.
- Private client acting as a consumer. Law 3/2004, on late payment, is not applicable: its Article 3 excludes 'payments made in commercial transactions involving consumers'. The Civil Code governs. Its Article 1108 states: 'Should the obligation consist of the payment of a sum of money, and the debtor is in default, the indemnity for damages and losses, in the absence of an agreement to the contrary, shall consist of the payment of the agreed interest, and in the absence of such agreement, the legal interest.' The legal interest rate is established annually by the applicable regulation, and I have not identified the regulation establishing it for 2026.
- Business or professional client acting as such. The late payment legislation may apply. Article 7 stipulates that, in the absence of an agreement, the default interest rate shall be the European Central Bank's most recent main refinancing operation rate plus eight percentage points. The Ministry of Economy publishes the resulting rate every six months. According to the resolutions of the General Secretariat of the Treasury and International Financing, it is 10.15% for the first half of 2026 (resolution of 23 December 2025, BOE of 31 December 2025) and 10.40% for the second half (resolution of 30 June 2026, BOE of 1 July 2026). Verify the resolution for the half-year in which your interest accrues.
Step 3: the monitorio procedure
The monitorio procedure is a judicial procedure designed for monetary debts that can be substantiated through documentation. It is governed by Articles 812 to 818 of the Civil Procedure Act.
- Debts covered. Article 812.1 permits the monitorio procedure for a monetary debt of any amount that is liquid, determined, due, and enforceable, evidenced by documents signed or sealed by the debtor, or by invoices, delivery notes, certifications, telegrams, telefax, or other documents customary in the relationship between creditor and debtor. Paragraph 2 adds the case where, alongside the debt document, commercial documents are provided that evidence a prior, lasting relationship.
- Without a lawyer or procurador. The initial petition may be submitted without them, regardless of the amount.
- Payment demand. The court requires the debtor to pay or lodge an objection within twenty days.
- Should the debtor neither pay nor lodge an objection. An application for execution may be filed. For such execution, the general threshold of 2,000 euros stipulated in Article 539.1 applies, beyond which representation by a procurador and the assistance of a lawyer are required.
- Should the debtor lodge an objection. The matter shall proceed to the appropriate trial based on the amount in dispute. The general threshold of 2,000 euros remains applicable to the juicio verbal.
Disputed debts and cases lacking sufficient evidence
If the client asserts that the work fails to meet the agreed specifications, or that payment has already been rendered, the debt is considered disputed and the monitorio procedure may culminate in a trial. In the absence of a quote, invoice, or supporting documentation, the monitorio procedure may prove unviable. I have not identified an official resolution confirming that messaging application logs or emails suffice in isolation; their admissibility is contingent upon their content, authenticity, and the documentary assessment of the specific case. Prior to initiating a claim with tenuous evidence, seek legal counsel.
Costs
For the initial monitorio petition, neither a lawyer nor a procurador is required. Law 10/2012 exempts natural persons from the payment of judicial fees (Article 4.2.a), and this exemption encompasses the monitorio procedure and its execution when the claimant is a natural person. If you claim as a natural person, you would not be liable for such fees. I have not ascertained the quantum of fees applicable to legal entities, which would not affect you unless you claim through a corporation. Costs may be incurred during the execution and trial phases.
If you are under 18
A minor shall claim through their parents or guardians, who serve as their legal representatives (Article 162 of the Civil Code). Consult Selling your drawings as a minor.
Points requiring clarification
- The legal interest rate under the Civil Code for 2026.
- The quantum of judicial fees for legal entities.
- Whether messaging logs, in the absence of an invoice, constitute sufficient documentation in a monitorio procedure: there is no identified official resolution to this effect.
- The effect of a formal notice of default on the calculation of interest.
Itineraries
I am going to sell or exhibit
Prior to accepting a commission, set out the quote, deadlines, and payment terms in writing, and request the client's acceptance. This constitutes the most effective prevention against non-payment.
An open conversation
This guide collates regulations and indicative templates. If you specialise in procedural law or debt recovery and can provide the prevailing interest rate, current fees, or criteria regarding evidence, you may contact me.
Sources
- Law 1/2000, on Civil Procedure (BOE), arts. 539, 812 to 818, 23 and 31.
- Law 3/2004, on measures to combat late payment (BOE), arts. 1, 3 and 7.
- Civil Code (BOE), arts. 162 and 1108.
- Resolution of 23 December 2025 regarding the default interest rate for the first half of 2026 (BOE-A-2025-27201).
- Resolution of 30 June 2026 regarding the default interest rate for the second half of 2026 (BOE-A-2026-14327).
- Law 10/2012, on judicial fees (BOE), art. 4.