diff --git a/stack.yaml b/stack.yaml
index c092d1d..8e55f30 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -18,6 +18,7 @@
 # snapshot: ./custom-snapshot.yaml
 # snapshot: https://example.com/snapshots/2024-01-01.yaml
 snapshot: nightly-2025-06-16
+compiler: ghc-9.12.1
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.