design CRISPR guides that work.

Paste a target DNA region. gRNA-Optimizer scans both strands for SpCas9 PAMs, scores each candidate guide for on-target efficiency (GC sweet-spot, homopolymer / Pol-III penalties, position preferences) and flags local off-target risk via the PAM-proximal seed. Returns a ranked, defensible guide table — transparent rules, not a black box.