mailparser is a Node.js library that parses raw MIME‑formatted email messages—including large ones—into a structured, easy‑to‑use format, exposing the data through streaming APIs. It’s aimed at developers building email‑handling or processing tools (e.g., mail clients, servers, or automation scripts) who need reliable, high‑performance extraction of headers, body parts, and attachments. (The project is now in maintenance mode; new projects are encouraged to use PostalMime.)