A GEDCOM validator is a tool that validates GEDCOM files;
it tells you whether the file contains any errors that need fixing.
Validators are created by developers for developers, but advanced users and genealogy software reviewers may want to use them too, to examine the quality of GEDCOM files produced by the genealogy software they use.
The Chronoplex GEDCOM Validator is a free product of Chronoplex (Andrew Hoyle), creators of Chronoplex Family Tree. The Chronoplex GEDCOM Validator is a Microsoft .NET application for Windows. The user interface is available in multiple languages. The Chronoplex GEDCOM Validator requires Windows and Microsoft .NET.
The Chronoplex GEDCOM Validator supports GEDCOM 5.5, GEDCOM 5.5.1. GEDCOM 5.5.5 support will be available soon.
VGedX is a command-line application for Windows, created by Tim Forsythe, the creator of Gigagtrees. The command-line application is complemented by a windowed configuration interface, available in multiple languages.
VGedX supports GEDCOM 5.5 and GEDCOM 5.5.1. VGedX is no longer being maintained.
GED-inline is a free on-line GEDCOM validator created by Nigel Munro Parker.
GED-inline supports GEDCOM 5.5, GEDCOM 5.5.1 and GEDCOM 5.5.5.
GedChk is a free GEDCOM validator by FamilySearch. GedChk is a command-line application for MS-DOS, for which only version 0.9 Beta dated 19 Oct 1998 is available. GedChk is mentioned here completeness' sake. GedChk is not well-behaved enough to run in a Windows DOS Box, but it does run in DOSBox, which is freely available for many operating systems.
GedChk supports GEDCOM 5.5 and 5.5.1. GedChk is no longer being maintained.