diff --git a/src/flatty/binny.nim b/src/flatty/binny.nim
index e5329cf..fe24e46 100644
--- a/src/flatty/binny.nim
+++ b/src/flatty/binny.nim
@@ -1,3 +1,6 @@
+when cpuEndian != littleEndian:
+  {.error: "flatty only supports little-endian native targets".}
+
 # Like StringStream but without the Stream and side effects.
 
 type Buffer = string | seq[uint8]