Programming Language Extensions
File extensions for every programming language (.py, .js, .rs…).
A searchable list of programming and markup languages with their file extensions — Python .py, JavaScript .js, TypeScript .ts, C++ .cpp, Rust .rs, Go .go, Ruby .rb and many more — grouped by category. Search by language or extension to identify a file or find the right extension, and tap to copy. Runs fully in your browser — no API.
How to use Programming Language Extensions
Open the list
Launch this free tool to look up file extensions for programming languages in one searchable table.
Search a language
Type a language like Python or Rust, or an extension like .py, to find the match.
Filter by category
Use the category filter to browse compiled, scripting, web, data or functional languages.
Read the extension
Each row shows the language and its common file extension(s).
Copy it
Tap a language or extension to copy it for your editor, config or upload filter.
Identify a file
Search an unknown extension (like .rs or .kt) to find which language it belongs to.
Frequently asked questions
What file extension does Python use?
Python source files use the .py extension. Compiled/bytecode files use .pyc. Search this list for any language to find its extension, or an extension to find the language.
How do I know which language a file extension belongs to?
Type the extension (like .rs, .kt or .go) into the search box and read the language column — .rs is Rust, .kt is Kotlin and .go is Go. The list covers the most common languages.
Why do some languages have several extensions?
Many languages use more than one extension for different file kinds — for example C++ uses .cpp, .cc and .cxx for source and .hpp for headers, and TypeScript uses .ts and .tsx. This list shows the common variants.
Is this the same as MIME types?
No — this maps languages to file extensions, while a MIME type is the media type sent over HTTP (like text/javascript). They're related but different; use our File Extensions & MIME Types tool for MIME types.
Is this tool free?
Yes — it's completely free with no sign-up. The list runs in your browser from a built-in dataset, so there are no limits, no API keys and nothing is uploaded.
What file extension does JavaScript, TypeScript or C++ use?
JavaScript uses .js (and .mjs/.cjs for modules), TypeScript uses .ts and .tsx, and C++ uses .cpp, .cc or .cxx for source with .h/.hpp for headers. Search any language in the list to find all its extensions.
How do I find out what language a file is written in?
Type the file's extension (like .rb, .swift or .kt) into the search box and read the language column — .rb is Ruby, .swift is Swift and .kt is Kotlin. It's the quickest way to identify an unfamiliar source file.
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