diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index db0d9c898..5fc8fd289 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -10,7 +10,7 @@ If you really want to open a new issue:
 * Please use the [search functionality](//github.com/almende/vis/issues) to make sure that there is not already an issue concerning the same topic.
 * Please make sure to **mention which module** of vis.js (network, timeline, graph3d, ...) your are referring to.
 * Note that development happens on the `develop` git branch. Be sure to submit PRs against this branch.
-* If you think you found a bug please **provide a simple example** (e.g. on [jsbin](jsbin.com)) that demonstrates the problem.
+* If you think you found a bug please **provide a simple example** (e.g. on [jsbin](https://jsbin.com)) that demonstrates the problem.
 * If you want to propose a feature-request please **describe what you are looking for in detail**, ideally providing a screenshot, drawing or something similar.
 * **Close the issue later**, when the issue is no longer needed.
 
@@ -45,4 +45,4 @@ Thank you to all our sponsors! (please ask your company to also support this ope
 <a href="https://opencollective.com/vis/sponsor/6/website" target="_blank"><img src="https://opencollective.com/vis/sponsor/6/avatar.svg"></a>
 <a href="https://opencollective.com/vis/sponsor/7/website" target="_blank"><img src="https://opencollective.com/vis/sponsor/7/avatar.svg"></a>
 <a href="https://opencollective.com/vis/sponsor/8/website" target="_blank"><img src="https://opencollective.com/vis/sponsor/8/avatar.svg"></a>
-<a href="https://opencollective.com/vis/sponsor/9/website" target="_blank"><img src="https://opencollective.com/vis/sponsor/9/avatar.svg"></a>
\ No newline at end of file
+<a href="https://opencollective.com/vis/sponsor/9/website" target="_blank"><img src="https://opencollective.com/vis/sponsor/9/avatar.svg"></a>