Abstract: Methods are disclosed for high throughput identification of optimized template-independent polymerase variants. The methods comprise generation of polymerase gene-encoding variants, isolation of variants, expression of variants, exposing expressed polymerase variants to desired conditions for activity, and identification of active variants, such as by hybridization to synthesized polynucleotides or by amplification. Encoding genes of active variants can be sequenced. The method can be performed iteratively to enhance generation and selection of preferred variants.