diff --git a/rust/bssl-crypto/README.md b/rust/bssl-crypto/README.md
index bc7371a..9518862 100644
--- a/rust/bssl-crypto/README.md
+++ b/rust/bssl-crypto/README.md
@@ -9,3 +9,6 @@
 ```
 
 Unlike BoringSSL itself, this crate does not attempt to handle allocation failures. If an allocation fails, functions in this crate will panic.
+
+WARNING - This crate is experimental and does *NOT* have a stable API. We expect to iterate on the API as it develops. If you use this crate you must be prepared to adapt your code to future changes as they occur.
+