After the announcement of the timetable for generalization of the electronic invoice for companies, between 2024 and 2026, the government has just published the "External specifications" folder of the device. Available online, this 78-page file, which is not intended to be a user guide, brings together all the documents describing the technical modalities of exchange with the public billing portal Chorus Pro. After a reminder of the context, objectives and regulatory framework, the second part gives a functional overview of the target solution, based on the so-called "Y" scheme adapted to the invoicing circuits between buyers, suppliers and dematerialization platforms. Above all, it specifies the "essential points" that are in particular the formats, the directory and the connection protocols. These elements will allow Acxias to refine the sound setting connector between Chorus Pro and SAP Ariba.