The goal of the experiment was to examine the relevance of a new French web-based assessment, Tinfolec (Test INFOrmatisé d'évaluation de la LECture), the aim of which is to evaluate the reading abilities of children in primary grades. The participants were 1,016 children from Grades 2 to 5. They completed the five tasks of Tinfolec designed to assess the efficiency of the two procedures used to identify written words (the nonlexical route and the lexical orthographic route). We tested the reliability and validity of the new tool in a subsection of this sample. Correlational analyses provided evidence of the reliability and validity of Tinfolec. The results are consistent with the conventionally observed effect of lexical factors (length, consistency, and frequency) on written word processing. The results confirm the relevance of the proposed tasks. The study produced promising results and would allow practitioners to perform online assessments of reading skills.