eSignature Legality Guide

Situations where a Standard Electronic Signature (SES) is generally suitable include:

• commercial contracts between companies, such as NDAs, purchase orders, order confirmations, invoices, procurement documents, sales agreements, distribution agreements, and service contracts
• consumer contracts, including documents for opening new retail accounts, sales terms, service terms, software licenses, purchase orders, order confirmations, invoices, shipping documents, user manuals, and policies, but not consumer loan agreements
• software licensing agreements
• intellectual property licenses, including those for patents, copyrights, and trademarks
• transfers of intangible property (e.g., assignments of patents or copyrights)
• submissions for public tenders

Examples where a type of electronic signature other than SES may be necessary include:

• AES – Issuing invoices (Article 3, Decree-Law No. 196/2007)
• AES – Intellectual property licenses and transfers (Decree-Law No. 36/2003)
• QES – Supported urban leases (Article 18, Law No. 81/2014)
• QES – Rural leases (Article 27, Decree-Law No. 294/2009)
• QES – Public contracts (Public Contracts Code and Law No. 96/2015)

Certain transactions are specifically excluded from digital or electronic processes, or require handwritten (wet ink) signatures or formal notarization, making them generally incompatible with electronic signatures or digital transaction management.

• contracts for the purchase or transfer of real estate (Article 875, Portuguese Civil Code)
• surety contracts (Article 627, Portuguese Civil Code), if this is the required form for the principal obligation
• consumer loan agreements exceeding €25,000 (Article 627, Portuguese Civil Code)
• stand-alone promises to perform an obligation (Article 413, Portuguese Civil Code)
• stand-alone acknowledgements of debt (Article 458, no. 2, Portuguese Civil Code)
• certain family law contracts, such as prenuptial agreements
• certain succession law contracts, including inheritance contracts (Article 2028, no. 2, Portuguese Civil Code), contracts waiving inheritance (Article 2063, Portuguese Civil Code), and inheritance sales (Article 2126, Portuguese Civil Code)
• residential lease agreements and their termination
• articles of incorporation and share assignments for limited liability companies (see Articles 4–A, 7, and 228 of the Code of Commercial Companies)
• mortgages (Article 688, Portuguese Civil Code)
• termination of employment contracts
• communications related to the Legal Regime of Urban Planning and Building (Article 8-A, Law No. 60/2007)
• notifications regarding the start of activity and real estate transactions before the Portuguese supervisory authority (InCI – Instituto da Construção e do Imobiliário) (Law No. 25/2008, together with Regulation No. 282/2011)

[1] An AES, or “advanced electronic signature,” is a type of electronic signature that: (a) is uniquely linked to the signer; (b) can identify the signer; (c) is created using means under the sole control of the signer; and (d) is connected to the signed data so that any changes can be detected.

[2] A QES is a specific form of digital signature that meets government-defined requirements, including use of a secure signature creation device, and is certified as “qualified” by the government or an authorized entity.

Portugal, as a country with a tiered eSignature legal model, recognizes Qualified Electronic Signatures (QES), which require independent accreditation by an approved certification authority. Although QES is only mandatory for certain transactions, as previously mentioned, Portugal—being an EU member—adheres to ETSI (European Telecommunications Standards Institute) standards for QES technical requirements. In line with the EU Directive 1999/93/EC on Electronic Signatures, Portugal maintains a publicly available list of supervisory bodies for qualified certificate providers, together with other EU countries.