Quba is a
e-Invoice-Viewer

Open-source / Free / Cross-Platform

Viewer for electronic invoices

We are Quba

Mustang's focusses on the creation, validation and parsing of electronic invoices. Validation checks the syntax and also re-calculates important parts of these invoices and there is also a Software-As-A-Service REST API available. Quba covers the visual display for manual checks.

Linux version works again

The good news in the 1.5.1. release was, that the auto-update feature worked, for the first time ever. The bad news was, that the Linux-version

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Quba 1.5.1

Today, May 1st, 2026, we released version 1.5.1 of our open-source e-invoice viewer Quba. This version fixes some minor issues, among others in it’s interface

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Quba 1.5.0

Quba 1.5.0 unterstützt auch ZUGFeRD 1 und bringt eine Suche und ein Handbuch.

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Quba on the FOSDEM

On the FOSDEM in Brussels Quba had a little guest appearance in the talk Europe’s Way to Mandatory B2B-E-Invoices of which a recording is available.

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Chat under the christmas tree

In order to mutually ask and answer questions Jochen suggests to just meet at the matrix.org #facturx room the next two Thursdays (26.12. and 02.01.)

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Chat under the christmas tree

In order to mutually ask and answer questions Jochen suggests to just meet at the matrix.org #facturx room the next three Thursdays (19.12., 26.12. and

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What about the name? Apart from being the name of a city in Azerbaijan, it also is the name of the horse breed originating from there. This name, like other horse names (Konic, Mustang) is a homage to the initiator of Factur-X / ZUGFeRD, the Forum of the Electronic Invoice Germany (“FeRD”, an accoustic allusion to the German word for horse).

Thank you for your support with the development of version 1.0

From now on community support and news are available via the ZUGFeRD Google Group.