Peptide Library is an independent, browser-based research platform designed to support the study of peptides. Its primary function is to aggregate and organize information on over 200 peptides, allowing users to search profiles, compare vendor pricing, calculate reconstitution concentrations, and track research protocols from a single interface. The platform does not sell peptides and explicitly states that its content is for research and educational use only, not for human consumption or as medical advice. The tool offers four core capabilities. The search feature enables users to look up peptide profiles by name, alias, molecular data, or reference from one field. The compare function lists vendor offers ranked by price per milligram, including ratings and availability, to help distinguish between the cheapest vial and the cheapest milligram. The calculate function resolves vial amount, diluent volume, and target dose into a calculated volume without leaving the screen. The track feature provides schedules, logs, inventory, notes, and metrics on a single timeline to maintain protocol consistency over time. Typical use cases include researchers who need to compare vendor offers across multiple peptides, calculate precise concentrations for reconstitution, and log dosing schedules and inventory. The platform replaces the need for multiple separate tools and spreadsheets by integrating search, comparison, calculation, and tracking into one workflow. Profiles are built from peer-reviewed literature, with citations recorded against PubMed identifiers and DOIs, ensuring the information is sourced from published research. Peptide Library is free to use and requires no account creation. It runs entirely in a web browser, making it accessible without installation. The platform does not host or sell peptides; it functions solely as a reference and organizational tool for the research community.