EmEditor is a lightweight extensible commercial text editor for Microsoft Windows.
It includes full Unicode support, 32-bit and 64-bit builds, syntax highlighting, find and replace with regular expressions, vertical selection editing, editing of large files (up to 248 GB or 2.1 billion lines), and is extensible via plugins and scripts.
[3] EmEditor supports Unicode and provides tools for work with various character encodings.
[4] For large files up to 248 GB, rather than opening them in memory, EmEditor "spills them out" into disk space.
The editor's API is available, so that users can write their own plug-ins.