Best Diagram Open Source Software

In this article, we are going to look at best diagram open source software. This software is freely available on the internet and it can be used in different operating systems like Linux, Mac and Windows. Some of the best diagram open source software are given below.

Funded by the National Science Foundation and developed by a team of talented individuals, Best Diagram is an open-source diagramming tool that provides a visually rich environment to create and share professional-looking diagrams. Best Diagram is freely available under GNU General Public License.



I reviewed Dia 0.97.3 from the Ubuntu 18.04 repository; you can download it here.

Dia is a standalone drawing tool. It offers some additional components, such as dia-rib-network for network diagrams and dia2cod for converting UML to code.

The installation process dragged in a few other packages, including: dia-commondia-shapesgsfonts-x11libpython-stdlibpythonpython-cairo, and python-gobject2.

Dia’s documentation is quite thorough and available in English, German, French, Polish, and Basque. It includes information on related utilities; versions for Linux, Windows, and MacOS; a lot of stuff related to shapes; and much more. The bug tracker on the project’s website is disabled, but bug reports are accepted on GNOME Bugzilla.

Dia has complete support for making flowcharts—appropriate symbols, connectors, lots of connection points on objects, annotation for objects, etc. Even so, Dia’s user experience (UX) feels unusual. For example, double-clicking on an object brings up properties and metadata, rather than the object’s annotation; to edit annotation, you must select the object and click on Tools > Edit Text (or use the F2 key). The default text size, 22.68pt, or about 8mm, seems a bit weird. The text padding default is very large (0.50), and even when it’s reduced by a factor of 10 (to 0.05), it still may leave a wide gap around the text (for example in the diamond decision object). You must also select the object before you can right-click on it. Cutting and pasting are somewhat limited—I couldn’t copy text from my browser (with the standard Ctrl+C) and paste it into Dia. Dia launches ready to work with a multipage drawing, which is pretty handy if you need to make a 1×2 meter drawing and your printer accommodates only letter-size paper.

In general terms, performance is very snappy. Interaction can seem a bit odd (see above), but it doesn’t require huge adjustments to get the hang of it. On the downside, the Help menu did not link properly to documentation, and I couldn’t find a spell checker. Finally, from what I can tell, there is no active development on Dia.

 LibreOffice Draw

LibreOffice Draw
LibreOffice Draw

LibreOffice Draw is part of the LibreOffice suite and features an easy-to-use UX, especially for users familiar with OpenOffice draw or LibreOffice Writer. You can produce powerful and intuitive flowcharts, organization charts, brochures, posters, network diagrams, and many other types of graphics. Its Open Document Format for Office Applications (ODF) and (.odg graphics extension) is also compatible with macOS and windows.

Important features

  • It features a gallery of shapes, drawings.
  • Import from a wide range of file formats like PDF and export to GIF, JPEG, PNG, SVG, WMF, and more.
  • It features predefined flowchart shapes, styles, & formatting tools to make posters and brochures.
  • It supports macro execution with Java.
  • Users can benefit from the extensive help facility from the help menu and extensive online resources.



I reviewed Inkscape version 0.92.3 from the Ubuntu 18.04 repositories; you can download it here.

Inkscape is a standalone tool, and it is waaaaaay more than a flowchart drawing utility.

The installation process dragged in several other packages, including: fig2devgawklibgtkspell0libimage-magick-perllibimage-magick-q16-perllibmagick+±6.q16-7libpotrace0libsigsegv2libwmf-binpython-scourpython3-scourscour, and transfig.

There is a great deal of Inkscape documentation available, including the Inkscape Manual available from the Help menu. This tutorial made it easier to get started with my first Inkscape flowchart.

Getting my first rectangle on the screen was pretty straightforward with the Create Rectangles and Squares toolbar item. I changed the shape’s background color by using the color swatches across the bottom of the screen. However, it seems text is separate from other objects, i.e., there doesn’t appear to be a concept of geometric objects with annotation, so I created the text first, then added the surrounding object, and finally put in connectors. Default text sizes were odd (30pt, if I recall correctly) but you can change the default. Bottom line: I could make the diagram, but—based on what I could learn in a few minutes—it was more of a diagram than a flowchart.

In general terms, Inkscape is an extremely full-featured vector drawing program with a learning curve. It’s probably not the best tool for users who just want to draw a quick flowchart. There seems to be a spell checker available, although I didn’t try it.


Graph Visualization Software (Graphviz) is an open-source and programmable graph drawing software. You can utilize this tool to create network diagrams, database connections, bioinformatics, and similar diagrams.


Important features

  • It features a collection of programs for graph visualization specified in DOT language scripts.
  • It features web and interactive graphical interfaces to display output.
  • Supports a wide range of formats such as images and SVG for web pages, Postscript, or PDF for inclusion in other documents.
  • Supports a wide range of colors, fonts, tabular node layouts, line styles, hyperlinks, and custom shapes.

Graphviz is a tool for users with projects to convert text to graphical representations, and you can get started from the official Graphviz documentation.



I reviewed Pencil version 3.0.4, which I downloaded from the Pencil project website. I used dpkg to install the 64-bit .deb package file. It installed cleanly with no missing packages.

Pencil is a standalone drawing tool. Documentation and tutorials are available on the project website.

To make my sample flowchart, I selected the flowchart shape set from the far-left menu panel. From there, I could drag Process, Decision, and Straight Connector shapes onto the page. I added annotation by double-clicking on the object and typing in the text. (Copy/paste also works.) You can drag the connector endpoints near the desired attachment point and they automatically attach. The default font setting (Arial, 12pt) is a good choice, but I couldn’t find a spell check function.

In general, using Pencil is very simple and straightforward. It offers solid flowcharting capability with no UX surprises and performs well, at least on smaller flowcharts.


This article explores the open source diagram software best. From it, you will find the pros and cons of each open source diagram software, the author’s recommended software, and the Best Open Source Software according to your needs.


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