CRISPR.org is a web-based tool for genome editing experiments using the CRISPR-Cas9 system. It identifies guide RNAs in an input sequence and ranks them based on scores that evaluate potential off-target effects and predict on-target activity. The tool supports over 150 genomes and provides comprehensive solutions for guide RNA selection, cloning, expression, and validation. Recent developments include batch design for genome-wide CRISPR and saturation screens, custom oligonucleotide design for guide cloning, and next-generation sequencing primer design for off-target mutation testing. CRISPR.org is available at http://crispor.org, including the full source code and a standalone command-line version. The tool helps users select guide RNAs by analyzing input sequences, genomes, and CRISPR nuclease types. It provides a graphical view of the input sequence with possible guide targets and a table of guide targets with predictive scores, off-target numbers, and locations. Users can filter guides by their first nucleotides and select guides for cloning, PCR primers, and validation. The tool also includes features for off-target primer design, batch oligonucleotide design for gene knock-out screens and non-coding saturating mutagenesis screens, and efficiency scores for non-SpCas9 nucleases. CRISPR.org supports the UCSC Genome Browser for genome editing experiments, providing pre-computed CRISPR results for various model organisms. It also includes batch primer design for off-targets and a tool for designing DNA donors for programmable sequence modifications. The tool has been updated to include support for base editors and CRISPRi/a, and it continues to rely on user feedback for improvements. The complete source code is available on GitHub, and the tool provides detailed documentation and a manual for users. CRISPR.org is a comprehensive resource for genome editing experiments, offering intuitive tools for guide RNA selection, design, and analysis.CRISPR.org is a web-based tool for genome editing experiments using the CRISPR-Cas9 system. It identifies guide RNAs in an input sequence and ranks them based on scores that evaluate potential off-target effects and predict on-target activity. The tool supports over 150 genomes and provides comprehensive solutions for guide RNA selection, cloning, expression, and validation. Recent developments include batch design for genome-wide CRISPR and saturation screens, custom oligonucleotide design for guide cloning, and next-generation sequencing primer design for off-target mutation testing. CRISPR.org is available at http://crispor.org, including the full source code and a standalone command-line version. The tool helps users select guide RNAs by analyzing input sequences, genomes, and CRISPR nuclease types. It provides a graphical view of the input sequence with possible guide targets and a table of guide targets with predictive scores, off-target numbers, and locations. Users can filter guides by their first nucleotides and select guides for cloning, PCR primers, and validation. The tool also includes features for off-target primer design, batch oligonucleotide design for gene knock-out screens and non-coding saturating mutagenesis screens, and efficiency scores for non-SpCas9 nucleases. CRISPR.org supports the UCSC Genome Browser for genome editing experiments, providing pre-computed CRISPR results for various model organisms. It also includes batch primer design for off-targets and a tool for designing DNA donors for programmable sequence modifications. The tool has been updated to include support for base editors and CRISPRi/a, and it continues to rely on user feedback for improvements. The complete source code is available on GitHub, and the tool provides detailed documentation and a manual for users. CRISPR.org is a comprehensive resource for genome editing experiments, offering intuitive tools for guide RNA selection, design, and analysis.