The GraphML File Format

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File Format Links
GXL - an XML-based graph exchange format developed for software re-engineering.

GML - a widely used graph exchange format (non-XML).

XGMML - an XML-based file format for graphs based on GML.

SVG - an XML-based graphics format.

Graph Drawing Links - home of graph drawing

GD 2010 - 18th Intl. Symp. Graph Drawing, 21-24 Sep 2010, Konstanz, Germany

XML Links
XML - home of the Extensible Markup Language at the World Wide Web Consortium.

What is GraphML?

GraphML is a comprehensive and easy-to-use file format for graphs. It consists of a language core to describe the structural properties of a graph and a flexible extension mechanism to add application-specific data. Its main features include support of

  • directed, undirected, and mixed graphs,
  • hypergraphs,
  • hierarchical graphs,
  • graphical representations,
  • references to external data,
  • application-specific attribute data, and
  • light-weight parsers.

Unlike many other file formats for graphs, GraphML does not use a custom syntax. Instead, it is based on XML and hence ideally suited as a common denominator for all kinds of services generating, archiving, or processing graphs.

Getting Started

An easy introduction to GraphML is the GraphML Primer.
GraphML Primer is a non-normative document intended to provide an easily readable description of the GraphML facilities, and is oriented towards quickly understanding how to create GraphML documents.
For normative references see the GraphML Specification.


GraphML is intended to be a service to the community. It may be used free of charge in scientific and commercial software alike.

Creative Commons License GraphML Working Group
This work is licensed under a Creative Commons Attribution 3.0 License.


Work on GraphML was initiated in a workshop during the 2000 Graph Drawing Symposium in Williamsburg, and a proposal for the structural layer was presented at the 2001 Graph Drawing Symposium in Vienna.

Since then, extensions have been provided that support basic attribute data types and the embedding of information for light-weight parsers. The next major steps will be extensions for abstract graph layout information and templates to transform such information into a variety of graphics formats.

Software to help add GraphML support to several popular tools and libraries is under development.

05 April 2007
Licensing status clarified: GraphML is free for everyone.
22 February 2007
GraphML 1.0 schema inclusion altered to avoid problems with some parsers.
03 August 2004
LEDA extension package for GraphML (release candidate).
01 June 2004
GraphML Primer released.
18 March 2003
XML Schema specification and documentation available for GraphML 1.0rc (release candidate)
23 July 2002
GraphML presentation at the annual meeting of DFG Research Priority 1126 Algorithmic Aspects of Large and Complex Networks. (ps, pdf)
28 June 2002
yFiles extension package for GraphML version 1.0 released.
22 May 2002
Release candidates for extensions graphml-attributes (for data attributes) and graphml-parseinfo (for lightweight parsers) completed. See current specification.
12 March 2002
GraphML proposed as the standard format for the network data archive to be created within EU FET Open Project COSIN.

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Last update: Wednesday, 17-Apr-2013 12:55:47 CEST