What is an ID file?
The .ID file extension is used for several different data formats. Most often, an .ID file is a Lotus Notes User ID File created by IBM. These files store user identification details, security certificates, and encrypted data for network access.
Because .ID has multiple possible meanings, your file could be something else entirely. It is also used as a temporary part file by SolidWorks, a map object index file by MapInfo Professional, an Adobe InDesign file, or a private identity key file by OpenSSH. In video games like Star Citizen, it functions as a JSON game build manifest file.
How to open ID files?
Because the .ID extension is shared by different programs, you must know the file origin to open it correctly. You might need IBM Lotus Notes for security files, SolidWorks for CAD data, or a text editor like Notepad++ for OpenSSH keys and JSON manifests.
If you are unsure about your file, viewer.online/id can analyze .ID files to identify the exact format and creator software, inspect the file structure, extract readable text, and check whether an online preview is available.
Software and tools
You can use the original software to open these files. For example, use the Valve Steam client for download cache files. If you need to change a text-based .ID file into another format, we recommend file conversion to sensible target formats on convert.guru. Text and code formats like JSON manifests or OpenSSH keys can easily convert to .TXT or .JSON.
Best practices and troubleshooting
Do not delete .ID files if they belong to a software installation. Temporary .ID files from SolidWorks will usually delete themselves when you close the program. If your email client asks for a Lotus Notes User ID File, you must provide the exact .ID file issued by your system administrator.
Summary
Since .ID files have many completely different uses, it is easy to get confused. This is why viewer.online/id is useful for identifying, inspecting, and understanding .ID files without installing software or dealing with compatibility problems.