The most recently developed genome editing system, CRISPR-Cas9 has greater inherent flexibility than prior programmable nuclease platforms. Because of its simplicity and efficacy, this technology is revolutionizing biological studies and holds tremendous promise for therapeutic applications. However, imperfect cleavage specificity of CRISPR-Cas9 nuclease within the genome is a cause for concern for its therapeutic application. To facilitate the adoption and improvement of this technology, we have developed CRISPRseek for designing target specific gRNAs, and GUIDEseq for identifying genome-wide offtarget sites from GUIDE-seq and CIRCLE-seq experiments to assess the precision of engineered CIRSPR-Cas9 nucleases. In this talk, I will give an introduction to the CRISPR genome editing, GUIDE-seq and CIRCLE-seq technologies, followed by an overview of the functionalities of CRISPRseek and GUIDEseq. By the end of talk, the participants should be able to design target-specific gRNAs for various cas9 nucleases and genomes using CRISPRseek, and analyze GUIDE-seq and CIRCLE-seq data using GUIDEseq.