GTF (gene transfer format) is a simple, precise format for annotating protein coding genes which has been used for a number of multi-group annotation efforts. It is a specialized subset of GFF (general feature format). The specification for GTF can be found here. If a GTF file contains errors, programs that parse it can yield false conclusions. Validate GTF is a flexible Perl script that checks a GTF file for correctness. It can detect most common syntactic errors, such as including the stop codon within the CDS annotation. It can also detect semantic errors, such as annotated coding sequence that contains stop codons spanning splice sites.