Gravizo is described as 'A simple way of describing graphs and include it easily in your web for free, blog, markdown page, github, and any location where remote images can be showed' and is an app in the Development category. There are six alternatives to Gravizo for a variety of platforms, including Windows, Linux, Mac, Online / Web-based and Android. The best alternative is PlantUML, which is both free and Open Source. Other great apps like Gravizo are Graphviz (Free, Open Source), Visual Paradigm (Paid), StarUML (Paid) and UMLet (Free, Open Source).
PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams. The generator can be run anywhere within JVM and integrated with various application such as wiki, text editor, IDE, programming language, documentation generator, and others.
Graphviz is open source graph visualization software. It has several main graph layout programs. It also has web and interactive graphical interfaces, and auxiliary tools, libraries, and language bindings.
Visual Paradigm for UML (VP-UML) is a UML design tool and UML CASE tool designed to aid software development. VP-UML supports key modeling standards such as Unified Modeling Language (UML) 2.4, SysML, ERD, DFD, BPMN 2.0, ArchiMate 2.0, etc.
UMLet is an open-source UML tool with a simple user interface: draw UML diagrams fast, export diagrams to eps, pdf, jpg, svg, and clipboard, share diagrams using Eclipse, and create new, custom UML elements.