Fiscal subject related
From the technical point of the view, it is generated through the RSA algorithm based on the following information:
- Date of issuing
- Date and time of the last alteration of the document
- Receipt number
- Total of the receipt (rounded to 2 decimals)
- The signature generated in the previous document, of the same series
- and on the private key of the computer invoicing program producer
It is important to state, that a digital signature needs to be recorded in the invoicing database (which cannot be encrypted), and is directly associated with the original document’s record. Also, the version of the private key (sequential integers) that was used to generate the signature of the respective document needs to be recorded.
Other news from Portugal
New document was uploaded: S4F backoffice patch
S4F backoffice patch is intended for users who have already installed S4F backoffice and are intended to update existing installations to latest version. To do so apply only patches that are marked with version number that is newer than your currently installed instance of backoffice. Please make sure to install all available patches sequentially (without skipping). This package contains instruction, release notes, changelog and software packages required for deployment of this software component. Read more
Subscribe to get access to the latest news, documents, webinars and educations.
Already subscriber? LoginAre tips subject to invoice and fiscalization requirements in Portugal?

In Portugal, tips (gratuities) are considered personal gestures to employees and are not subject to VAT, nor do they need to be included on invoices. Let's delve deeper into this topic! Read more
Subscribe to get access to the latest news, documents, webinars and educations.
Already subscriber? LoginNew document was uploaded: S4F backoffice patch
S4F backoffice patch is intended for users who have already installed S4F backoffice and are intended to update existing installations to latest version. To do so apply only patches that are marked with version number that is newer than your currently installed instance of backoffice. Please make sure to install all available patches sequentially (without skipping). This package contains instruction, release notes, changelog and software packages required for deployment of this software component. Read more
Subscribe to get access to the latest news, documents, webinars and educations.
Already subscriber? LoginPortugal strengthens Finance portal security with Two-factor authentication.

Portugal’s Tax Authority has introduced Two-Factor Authentication (2FA) on the Finance Portal, starting with individual taxpayers, to enhance account security and prevent unauthorized access. Users will log in using their NIF, password, and a unique SMS code, provided they have a registered phone number with the authority. The Portuguese Tax Authority (AT) has introduced Two-Factor Authentication... Read more
New rules for invoices issued on the Finance Portal of the Tax administration in Portugal

Starting July 1, 2025, Portugal’s Tax Portal no longer allows businesses to issue unfilled or blank invoices and invoice-receipts, requiring all documents to be completed digitally at the time of issuance. Invoices not collected by July 14, 2025, or used beyond the transitional period, will be canceled, and any unused forms must be destroyed to comply with the new rules. As of 1 July 2025, the Por... Read more
New webinar was uploaded: Recorded webinar: EV Chargin in Europe - Green Growth Meets Fiscal Reality
On June 19th, 2025, Fiscal Solutions organized a free webinar on the topic of "EV Charging in Europe—Green Growth Meets Fiscal Reality." The webinar was held by Fiscal Solutions Sales Manager Gordana Lakić. Let’s find out more on this! Read more
Subscribe to get access to the latest news, documents, webinars and educations.
Already subscriber? LoginNew document was uploaded: S4F backoffice patch
S4F backoffice patch is intended for users who have already installed S4F backoffice and are intended to update existing installations to latest version. To do so apply only patches that are marked with version number that is newer than your currently installed instance of backoffice. Please make sure to install all available patches sequentially (without skipping). This package contains instruction, release notes, changelog and software packages required for deployment of this software component. Read more