The FNMT certificate is the digital signature your invoicing software needs to comply with VeriFactu and issue legally valid invoices in Spain. Without it, no SIF can sign your records. This article explains what it is, how to apply for it step by step, and how to load it into InvoSeal in under five minutes.
If you already have a digital certificate — the same one you use to sign in the AEAT Electronic Office — you probably already have what you need. If not, it's time to get one. The process is not complicated, but it has its own pace. Let's break it down.
What is the FNMT certificate and why do you need it?
The FNMT-RCM (Spain's Royal Mint and Stamp Factory) issues recognised electronic certificates that allow you to identify yourself digitally before any Spanish public administration. In the context of VeriFactu and electronic invoicing, the certificate serves two functions:
- Authenticating you as an invoice issuer. Your tax ID (NIF) linked to the certificate guarantees that invoices are issued by who they say.
- Digitally signing billing records. RD 1007/2023 requires each record to carry a cryptographic fingerprint that makes it tamper-proof.
Without a valid certificate, no SIF (Billing IT System) can meet the integrity requirements that VeriFactu demands.
Types of FNMT certificate: which one do I need?
| Type | For whom | Cost |
|---|---|---|
| Natural Person Certificate | Self-employed (acting with their DNI/NIE) | Free |
| Legal Entity Representative Certificate | Directors of SL, SA, cooperatives… | Free |
| Entity without Legal Personality Certificate | Homeowner communities, estates under administration… | Free |
All three are free. The difference is who signs: you as a natural person, or you as the legal representative of your company.
Practical tip: if you are self-employed, the natural person certificate is sufficient and easier to obtain. If you are the director of an SL, you need the legal entity representative certificate.
How to get the FNMT natural person certificate step by step
- Online application. Go to sede.fnmt.gob.es and click "Obtain Software Certificate". Enter your DNI/NIE and email. You will receive a request code.
- In-person accreditation. With the code in hand, go to any AEAT office, Social Security registry, or accredited Town Hall. Bring your original DNI (no photocopies). They verify your identity and stamp the application.
- Certificate download. Return to the same computer where you made the request. On the same page, enter the request code and download the
.p12(or.pfx) file. Set a strong password: you will need it to import it. - Backup copy. Store the
.p12in two different places (USB drive + encrypted cloud). If you lose it, you have to repeat the entire process.
Total time: between 2 and 5 days if you can get an in-person appointment quickly. The bottleneck is always the in-person accreditation.
Alternative option: with DNIe or Cl@ve
If you have the electronic DNI (the DNIe with chip) and a card reader, you can get the certificate without leaving home: accreditation is done online. The same applies if you already have Cl@ve Permanente (advanced level). If you have neither, you'll need to visit an office.
Certificate validity and renewal
- Duration: FNMT certificates are valid for 4 years (natural person) or 2 years (legal entity).
- Renewal: you can renew online from the FNMT's own website during the 60 days before expiry, without needing to visit an office. You will receive an email reminder.
- If it expires unrenewed: you will have to repeat the full process, including in-person accreditation.
How to load your FNMT certificate into InvoSeal
- Log in to your account at app.invoseal.es.
- Go to Settings → Electronic Signature.
- Click "Upload certificate" and select your
.p12or.pfxfile. - Enter the certificate password.
- InvoSeal will verify the certificate and show your name, NIF, and expiry date.
From that moment on, InvoSeal uses your certificate to automatically sign each invoice you issue. No further configuration is required: the process is completely transparent.
Frequently asked questions
Can I use the same certificate with multiple programs?
Yes. The .p12 file can be imported into multiple programs. There is no restriction from the FNMT.
Can the certificate be revoked if stolen?
Yes. From the FNMT website you can revoke the certificate immediately. Once revoked, any signature that attempts to use it is automatically rejected.
Does a self-employed person's certificate work for their company's invoices?
It depends. If your business is you (self-employed in your own name), yes. If you have a limited company (SL) and you are the director, you need the legal entity representative certificate.
Load your FNMT certificate into InvoSeal in five minutes
InvoSeal automatically detects your certificate data, verifies its validity, and starts signing your invoices from the first moment. No additional setup needed to comply with RD 1007/2023.
Try InvoSeal free for 14 days →