Here’s a web-based application designed to help writing teachers give formative feedback to students effectively and efficiently. The application is not an electronic grader; in fact, every teacher comment becomes part of the rich data analytics that can guide instruction and monitor progress. Their innovative approach enables teachers who use the tool (WriterKEY) to give better, more targeted feedback to students because the application helps teachers focus on the link between assessment and instruction. Their tools make the process of responding to writers and giving feedback more efficient, helping teachers save time. They help teachers teach writers, not just writing. Popular tools include: Similarity Index, Writer’s Workshops; rubric builders, and portfolios that build reflection at every step. Although WriterKEY tools and content are fully aligned to the Common Core State Standards, the standards alignment is not the core of the resource. The application includes learning activities designed to help students improve their writing skills using the same tools as teachers to analyze writing, building familiarity and skills as they learn. WriterKEY is both an assessment feedback tool and an instructional tool in a single application.