How to Set Up Chave Movel Digital in Portugal (CMD for the AT Portal)

The AT portal requires authentication before you can do anything: file IRS, view your tax situation, register a new invoice series, access document records. Chave Movel Digital (CMD) is the credential most foreign freelancers end up needing. Portal das Financas also accepts a portal-specific password, but CMD works across every Portuguese government portal with one credential, and some operations (including Empresa Online company registration) require it specifically.

This page covers the setup. If you already have CMD and need to use it to file your IRS, see the IRS filing guide.

What you need before you start

• Your NIF (the 9-digit Portuguese tax number). If you do not have one yet, that comes first.
• A valid photo ID: passport, or your Portuguese residency card (Autorizacao de Residencia).
• A Portuguese mobile number. CMD sends one-time codes to this number every time you log in. Set this up before your activation appointment.

You do not need to be a Portuguese citizen. EU citizens, non-EU residents with a residency permit, and foreign nationals interacting with Portuguese tax authorities can all activate CMD.

How to activate CMD

In-person activation (the reliable route for most expats)

Go to a Loja do Cidadao or a local Financas service centre. Bring your NIF, ID, and have your mobile number ready. The agent registers your phone number and issues your CMD credentials on the spot. Activation takes about 10-20 minutes once you are at the counter. Wait times vary; booking an appointment online through agendamento.gov.pt saves time.

Online activation (requires a Cartao de Cidadao with chip)

Portuguese citizens with an activated Cartao de Cidadao chip and a compatible card reader can activate CMD entirely online at autenticacao.gov.pt. Most foreign freelancers do not have a CC, so in-person is the path.

What CMD gives you access to

Once activated:

• Portal das Financas (portaldasfinancas.gov.pt) - IRS filing, VAT declarations, invoice series registration, tax situation overview
• Seguranca Social Direta (app.seg-social.pt) - quarterly SS declarations, contribution records
• ePortugal (eportugal.gov.pt) - public services, certificate requests
• Empresa Online - company registration (CMD required, not optional)

Same credential, same phone, all of them.

Logging in to Portal das Financas with CMD

On the Portal das Financas login screen, choose "Autenticar com Chave Movel Digital." Enter your CMD username (your registered phone number or NIF), your PIN, and then the one-time code sent to your mobile. The whole login takes about 30 seconds once you know the flow.

The portal remembers your session for a limited time. If you step away and come back, you may need to log in again.

Keeping CMD working

CMD is tied to your mobile number. If you change your number, update it in autenticacao.gov.pt before losing access to the old one. Losing access to the registered number means an in-person reset visit, which takes more time than you want during IRS filing season.

The PIN can be reset online at autenticacao.gov.pt if you still have the linked mobile number.

Next step

CMD gets you into Portal das Financas. What to do once you are in depends on what you are trying to accomplish:

• To file your annual IRS declaration: How to file IRS Modelo 3 in Portugal
• To read and understand a previous IRS declaration you filed: IRS Declaration Reader
• To register a new invoice document series (required for certified invoicing): do this via Portal das Financas under Servicos, Faturacao, Comunicacao de Series Documentais