Does GSEA have a programmatic API? What languages are supported?
The Broad Institute provides R and Java APIs on the Downloads page. John Aach (Department of Genetics, Harvard Medical School) implemented a simplified version of the GSEA algorithm in MATLAB as part of the paper Global gene expression of Prochlorococcus ecotypes in response to changes in nitrogen availability. Aach notes that the MATLAB code supports only that portion of the GSEA algorithm required for the paper: it processes a particular file format, its significance calculations are performed by shuffling genes only and not phenotypes, and it does not include multiple hypothesis corrections for different gene sets.