diff --git a/docs/simplesamlphp-sp.txt b/docs/simplesamlphp-sp.txt
index 215ab1dbeb2e6cce2bfbd40ba4a45fe1bfbdb89c..ce6328332c3d35cca6282c1b2f02b639fd0ea0e3 100644
--- a/docs/simplesamlphp-sp.txt
+++ b/docs/simplesamlphp-sp.txt
@@ -140,6 +140,8 @@ The test page should contain a list of your attributes:
 Integrating authentication with your own application
 ----------------------------------------------------
 
+The API is documented in [the SP API reference](http://rnd.feide.no/content/simplesamlphp-sp-api-reference).
+
 For those web resources you want to protect, you must add a few
 lines of PHP code: