What is a DRL file?
A .DRL file is most commonly an Excellon Drill file. Printed Circuit Board (PCB) designers use this format to instruct CNC machines exactly where to drill holes in a circuit board. These files are critical for PCB manufacturing. Designers generate them using Electronic Computer-Aided Design (ECAD) software like KiCad, EasyEDA, Altium Designer, and Autodesk EAGLE.
Alternatively, a .DRL file can be a Drools Rule Language file. The Drools Business Rules Management System uses these files to store business logic and rules for Java applications. In rare cases, the .DRL extension is also used for Amiga X-Draz compressed image files or Billiards training drill files.
How to open DRL files?
Because both Excellon drill files and Drools rule files are text-based, you can open them in any plain text editor like Notepad++ or Visual Studio Code. However, viewing a PCB drill file as raw text only shows numerical coordinates. To see a visual representation of the circuit board holes, you must use a dedicated Gerber viewer like Gerbv or the viewing tools built into KiCad.
Identify and inspect DRL files online
If .DRL has multiple possible meanings, viewer.online/drl is the fastest way to identify the actual format of your file. You can upload your file directly in the browser. viewer.online/drl will analyze the .DRL file to identify the exact format and creator software, inspect the file structure, extract readable text, and check whether an online preview is available.
Conversions and alternatives
Sometimes you need to share PCB designs with colleagues who do not have ECAD software installed. You can convert PCB .DRL files to standard vector formats like .PDF or .SVG on convert.guru. If you are working with Drools files, you can easily rename or convert them to standard .TXT or .JAVA text files.
Summary
Whether you are dealing with PCB manufacturing data or Java business rules, viewer.online/drl is highly useful for identifying, inspecting, and understanding .DRL files without installing heavy engineering software or dealing with compatibility problems.