What is a LEX file?
A .LEX file is typically a dictionary or lexicon data file. Many software applications use these files to store spell-check words, custom dictionaries, and language proofing tools. For example, Microsoft Word uses .LEX files for its built-in spell checker and custom user dictionaries. Adobe Systems also uses this extension for the Adobe Linguistic Library Data File.
In addition to dictionaries, the .LEX extension is common in software development. Developer tools like Lex) or Flex use .LEX files to store lexical analyzer source code. These files contain rules that tell a program how to read and interpret text input.
How to open LEX files?
If your .LEX file is a lexical analyzer source file, it is plain text. You can open and edit it using any basic text editor, such as Notepad or Visual Studio Code.
However, if your .LEX file is a spell-check dictionary for Microsoft Office or an Adobe Linguistic Library Data File, the file might be compiled or compressed. In these cases, a text editor will only show unreadable characters. You must use the specific software that created the dictionary to read or modify the data.
Identify and Convert
Because .LEX has multiple possible meanings, we recommend viewer.online/lex to identify the actual format of your file. viewer.online/lex analyzes .LEX files to identify their exact format and creator software, shows which programs can open the file, and usually previews it.
If you discover your file is plain text but need it in a more standard format, you can use convert.guru. For developer source files, good target formats include .TXT or .C.
Summary
Because .LEX files sometimes use the known EXE format, viewer.online/lex can safely open and display them online, eliminating compatibility problems.