diff --git a/Contributing.md b/Contributing.md
index 41fb602..c9cfff5 100644
--- a/Contributing.md
+++ b/Contributing.md
@@ -15,11 +15,11 @@ Below is an overview of how to contribute code to the PDF.js project. The basic
 ### Prerequisites
 * Git client
 * GitHub account
-* [Node.js](http://nodejs.org/)
+* [Node.js](https://nodejs.org/)
 * Gulp (via `npm install -g gulp-cli`)
 * An ES6 compatible browser
 
-If you develop on Windows, read [[Setting up pdf.js Development Environment for Windows]]. For font testing you will need [Python](http://www.python.org/download).
+If you develop on Windows, read [[Setting up pdf.js Development Environment for Windows]]. For font testing you will need [Python](https://www.python.org/download).
 
 _Before you make any changes to the code you will probably want to jump down to the "Generating reference images" section to create the reference snapshot images so you can run the test framework and check for regressions._