Frequently asked questions about digital signatures

Yes! The Free plan includes:

• 2 CMD (Digital Mobile Key) signatures
• 5 Local Digital Certificate signatures
• 5 signatures without a certificate
• 1 document send to third parties
• 1 user
• 250MB of storage
• Email notifications

These are one-off allowances that do not renew. When they run out, buy a pack of sends (from €4.99 + VAT, 6 sends) or subscribe to a plan from €49/month + VAT.

Yes, fully.

We comply with the eIDAS Regulation (European Union) and Portuguese law.

Signatures made with the Digital Mobile Key (Chave Móvel Digital) are qualified electronic signatures: they have the legal effect of a handwritten signature (Article 25 of eIDAS), and the document counts as a private document with recognised authorship (Article 376 of the Portuguese Civil Code).

No. AssinaJá works 100% in the browser. You can use it on a computer, tablet or mobile phone.

The Digital Mobile Key (Chave Móvel Digital) is the Portuguese State's digital identification system.

It lets you sign documents with the highest legal validity using only your mobile phone.

It is included in every plan, including Free.

Professional Attributes let you sign documents in your certified professional capacity — for example:

• Lawyers
• Doctors
• Engineers
• Accountants

AssinaJá is the only platform that integrates Professional Attributes natively. Included in the Growth and Enterprise plans.

Yes! With templates and mail merge (Launch, Growth and Enterprise plans), you can send dozens or hundreds of personalised documents at the same time.

Common use cases:

• Staff onboarding
• Contracts in bulk
• Mass sending of proposals

Both! AssinaJá is for:

• Individuals — rental agreements, sales, declarations
• Businesses — commercial contracts, HR, suppliers

From occasional personal use to large organisations.

You can upgrade at any time.

If you are on Free and only need to send a few more documents, buy a pack of sends (from €4.99 + VAT, 6 sends); if you send regularly, switch to a paid plan.

You can also buy extra resources individually:

• CMD signatures
• SMS notifications
• Additional storage

No penalties or long contracts.

It does, in two places:

• On the signing screen, the Explain this document button answers questions about the contract in front of you — what it obliges you to do, what is unusual in it, whether you can cancel.
• In the editor, you describe in words where each person signs and the assistant places the signature areas, always showing you the plan before applying it.

The explanation is a reading of the document, not legal advice.

Yes. AssinaJá has an official MCP server, and the assistant you already use can prepare documents, tell you who still has to sign and bring you the signed PDF, without leaving the conversation.

Access is granted with a key, with the permissions you choose, and can be revoked at any time.

Step-by-step instructions are in the help centre, at help.assinaja.pt/en/.

No. The AI prepares and explains; signing and sending still require a person.

The editor's assistant always shows what it is going to do before it touches the document, and sending is always your step.

The first time you use it, you are asked to accept the feature's terms.

There are two types of digital documents:

• Native electronic document — created using only digital tools or processes, transmitted and kept in digital format
• Digitised electronic document — results from converting analogue (paper) information into digital information (scanning)

Under Portuguese law, any document containing scanned signatures is subject, as evidence, to the court's free assessment of evidence.

A general principle of equivalence applies between digital documents and documents on physical media (with some exceptions regarding evidential value).

This equivalence applies to:

• Correspondence in general (emails, letters, etc.)
• Invoices and bank statements
• Forms and purchase orders
• Brochures and technical content
• Administrative records
• Contracts

Yes, except where Portuguese law requires additional formalities (a public deed, authenticated documents or certification of signatures).

Examples of exceptions:

• Transfer of real estate and creation of mortgages
• Incorporation of companies
• Documents that serve as an enforceable title (e.g. acknowledgement of debt)
• Powers of attorney for acts that require additional formalities
• Loan agreements for more than €25,000

Yes. The applicable legal framework includes:

• Regulation (EU) No 910/2014 (eIDAS)
• Decree-Law No 290-D/99, as amended by Decree-Law No 88/2009

General principle: an electronic signature cannot be denied legal effect merely because it is in electronic form.

There are several types of digital signature, and the differences between them mainly affect the evidential value of the signed documents.

As a rule, whoever has powers to sign on behalf of a company should do so personally, applying their own signature.

They should not sub-delegate those powers to another person (e.g. pasting a scanned signature).

Exception: for simple contracts, the company may expressly authorise sub-delegation, for example:

• By resolution of the board of directors
• Through approved signature policies

Sub-delegation may be made to another member of the board or to an employee.

If you need to sign in a particular jurisdiction (e.g. for tax or regulatory reasons), caution is advised.

In principle, the main factor is the signatory's physical location at the time of signing.

However, this view is not free from doubt — the location of the server where the document is stored may also be considered relevant.

There are many ways to sign by electronic means, and they must serve the same purposes as a handwritten signature:

• Unequivocal identification of the signatory
• Application dependent solely on the holder's will
• Preservation of the document's integrity

Using specific software is not mandatory. However, dedicated platforms offer advantages:

• Certification of the signatories' identity
• Evidence of the signature (IP address, access passwords)
• Reduced risk of error or fraud

Yes, a document can be signed with a combination of different signatures (handwritten and digital), provided each signatory uses a valid method.

If the signatory has no access to a scanner, a digital photograph of the signature page may be an alternative.

For practical reasons, all signature pages should be clearly visible.

Under the Portuguese Civil Code, documents can be:

• Authentic — drawn up by public authorities, a notary or a public official vested with public faith
• Private — all other documents

An electronic document with a qualified electronic signature is equivalent to a private document with recognised authorship (Article 376 of the Civil Code).

Data in electronic form logically associated with other data used by the signatory to sign.

Evidential force: private document subject to the judge's free assessment.

Examples:

• Scanned handwritten signatures
• Biometric keys (fingerprint, iris, facial shape, voice)

An electronic signature that meets the following requirements:

• Uniquely linked to the signatory
• Capable of identifying the signatory
• Created using data under the signatory's sole control
• Linked to the signed data so that any subsequent change is detectable

Evidential force: private document subject to the judge's free assessment.

Examples: secret codes (passwords, PIN), cryptographic signatures through electronic signature platforms.

A qualified electronic signature created by a qualified device, based on a qualified certificate for electronic signatures.

Evidential force: private document with recognised authorship — the highest level.

Examples:

• Citizen Card (Cartão de Cidadão)
• Digital Mobile Key