diff --git a/docs/the_nimbus_book/src/rest-api.md b/docs/the_nimbus_book/src/rest-api.md
index faf8f9981..55e689c52 100644
--- a/docs/the_nimbus_book/src/rest-api.md
+++ b/docs/the_nimbus_book/src/rest-api.md
@@ -17,3 +17,15 @@ The specification is documented [here](https://ethereum.github.io/beacon-APIs/).
 
 See the Readme [here](https://github.com/ethereum/beacon-apis).
 
+## Quickly test your tooling against Nimbus
+
+ The [Nimbus REST api](https://nimbus.guide/rest-api.html) is now available from:
+ 
+* http://testing.mainnet.beacon-api.nimbus.team/
+* http://unstable.mainnet.beacon-api.nimbus.team/
+* http://unstable.prater.beacon-api.nimbus.team/
+
+
+Note that right now these are very much unstable testing instances. They may be unresponsive at times - so **please do not rely on them for validation**. We may also disable them at any time.
+
+