The CasPlus platform pairs Cas nucleases with an engineered DNA repair enzyme to achieve high editing efficiency while minimizing unwanted genomic modifications. CasPlus can potentially work with different Cas nucleases to enable the correction of diverse mutations. CasPlus has wide applicability and superior editing efficiency compared to existing technologies with the ability to produce 1 -3 base pair insertions in a predictable and template-free approach. These attributes uniquely position CasPlus within the toolbox of gene editing technologies.