Windows
Compatible applications
Quick Facts
Basic information about this file format
Extension
.LSP
File Type
Lisp Source Code File
Category
Programming
Best first step
Use compatible software
Quick Summary
A practical overview of the .lsp file format
An LSP file is a source code file written in the Lisp programming language, which is one of the oldest and most influential high-level programming languages in existence. Lisp is characterized by its unique syntax, which relies heavily on nested parentheses and prefix notation. In modern technical…
File extension
.LSP
File type
Lisp Source Code File
Category
Programming
Recommended action
Open with a trusted compatible app
How to open a .lsp file
Start with a trusted app that supports this format
- Check the file extension carefully and confirm that the file name really ends with .lsp.
- Use software that supports this file type. If one app does not work, try another compatible program for the same platform.
- Update the application if the file was created by a newer version of the software.
- Scan files from unknown sources before opening them, especially documents, archives, scripts, installers, and executable files.
What is a .lsp file?
File extension details and usage information
An LSP file is a source code file written in the Lisp programming language, which is one of the oldest and most influential high-level programming languages in existence. Lisp is characterized by its unique syntax, which relies heavily on nested parentheses and prefix notation. In modern technical workflows, the .lsp extension is most frequently associated with AutoLISP, a specialized dialect of Lisp used specifically for automating tasks within Autodesk AutoCAD. These files allow users to create custom commands, automate repetitive drawing sequences, and extend the core functionality of CAD software. Because LSP files are saved in a plain text format, they can be opened, read, and edited by any standard text editor. When the file is loaded into a Lisp interpreter or a CAD environment, the code is parsed and executed to perform complex mathematical calculations or manipulate data structures. Beyond CAD applications, .lsp files are used in various functional programming environments, artificial intelligence research, and symbolic processing tasks where the language's ability to treat code as data provides significant advantages for developers.
Software Compatibility
Programs that may open or work with .lsp files
macOS
Compatible applications
Linux
Compatible applications
Mobile
Mobile applications
Can .lsp files be converted?
Options for saving or exporting this file to another format
In many cases, a .lsp file can be converted by opening it in compatible software and using an option such as Save As, Export, or Convert. The available output formats depend on the file type and the application used.
- Use the original software that created the file when possible.
- Check whether the application supports exporting to common formats.
- Be careful with online converters when working with private, business, or sensitive files.
- If conversion fails, the file may be corrupted, incomplete, encrypted, or not actually a .lsp file.
Why can't I open a .lsp file?
Common reasons this file type may not open correctly
Wrong software
The file may require a specific program that supports the .lsp format.
Incorrect extension
The file extension may have been renamed manually, even though the actual file format is different.
Corrupted file
The file may be incomplete, damaged during download, or transferred incorrectly.
Outdated app
Your software may need to be updated before it can open newer versions of this file format.
Frequently Asked Questions
Common questions about .lsp files
To open a .lsp file, use software that supports this file format.
- Autodesk AutoCAD
- Visual Studio Code
- Notepad++
- GNU Emacs
- Steel Bank Common Lisp (SBCL)
Open the file in compatible software and look for options such as Save As, Export, or Convert. If no export option is available, the file may require a specialized converter or the original application that created it.
- Verify that the file extension is correct.
- Install or update compatible software.
- Try another application that supports this format.
- Check whether the file is corrupted, incomplete, or encrypted.
A file extension alone does not guarantee whether a file is safe or unsafe. Only open files from trusted sources, scan unknown files before opening them, and be especially careful with executable, script, archive, and document files.
File safety tips
Use caution with unknown files
Only open files from trusted sources. Before opening a .lsp file, scan it with antivirus software, verify that the file extension is expected, and avoid running unknown executable, installer, macro-enabled document, or script files.