GEDCOM X

June 29, 2023

GEDCOM X is a series of specifications for an open data model and an open serialization format to exchange data essential to the genealogical research process. The FamilySearch API is built on these specifications.

GEDCOM X uses standard protocols and follows best practices in the field of data exchange. The specification details structures for transferring genealogical data between both online and offline systems, including models for conclusions, source metadata, contributor metadata, and place and date formats. GEDCOM X provides for bundling media, such as photos, stories, documents, movies, and audio files, along with text-based, lineage-linked data. GEDCOM X also handles source descriptions, source references, citations, and evidence references that support genealogical conclusions.

GEDCOM X code is opened under an Apache II license. Other content is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

The GEDCOM X Project

FamilySearch sponsors the GEDCOM X project as an offering to the genealogical community and provides hosting, tools, forums, and dedicated developers in an effort to bring relevant technologies to bear in updating the representation, transmission, and storage of genealogical data. In addition to FamilySearch developers, technically proficient members of the genealogical community have been actively involved in a series of public online discussions dealing with the technical issues of how best to model genealogical data, handle sources and citations, standardize constrained vocabulary, define place and date formats, support the inclusion of digital artifacts, exchange data—all with an eye to supporting the genealogical research process and the elements of the Genealogical Proof Standard.

GEDCOM X is designed for the long-term. Through the implementation of solid design principles and engagement with the community, the GEDCOM X Project has every prospect of becoming a well-established mechanism for providing a rich and collaborative environment for the noble work of genealogical research.

The core specification set includes

The GEDCOM X Conceptual Model specifies an abstract conceptual model for genealogical data, independent of any serialization format.
The GEDCOM X XML Serialization Format specifies how to represent the conceptual model in XML.
The GEDCOM X JSON Serialization Format specifies how to represent the conceptual model in JSON.
The GEDCOM X File Format specifies how to bundle genealogical data into a file.

In addition to the specification set, FamilySearch maintains the GEDCOM X Java libraries as well as the GEDCOM 5.5 to GEDCOM X Conversion Utility that you can use to convert GEDCOM 5.5 files to GEDCOM X files.

For more information about the GEDCOM X project, see the project home page, the Developers Guide for GEDCOM X, and the UML diagram.

Why a New Specification?

In a nutshell, legacy GEDCOM lacked a well-defined source model, had insufficient support for the Genealogical Proof Standard, and provided no way to bundle multimedia files with the lineage-linked text data. Over the years, proprietary extensions created incompatibilities between implementations that resulted in unacceptable data loss. The GEDCOM specification also had not had a major update since GEDCOM 5.5 and consequently had not benefited from advances in web technologies or innovations in digital media.

An updated specification would need to:

Support the same core data that legacy GEDCOM supported.
Provide well-defined places for data not supported by legacy GEDCOM.
Support better handling of sources by providing well-defined places for source data.
Support digital artifacts in a zipped bundle of resources.
Provide for extensibility.
Define how genealogical data can move to, be stored in, and exchanged with web applications.