diff --git a/readme.md b/readme.md
index 67bbd1d..23fa34c 100644
--- a/readme.md
+++ b/readme.md
@@ -33,6 +33,6 @@ Please read the [contribution guidelines](contributing.md) first.
 
 ## License
 
-[![CC0](https://licensebuttons.net/p/zero/1.0/88x31.png)](http://creativecommons.org/publicdomain/zero/1.0/)
+[![CC0](https://licensebuttons.net/p/zero/1.0/88x31.png)](https://creativecommons.org/publicdomain/zero/1.0/)
 
 To the extent possible under law, [Matias Singers](http://mts.io) has waived all copyright and related or neighboring rights to this work.