diff --git a/crates/compiler/builtins/roc/Encode.roc b/crates/compiler/builtins/roc/Encode.roc
index b63ad2f35ba..a426a5fe78a 100644
--- a/crates/compiler/builtins/roc/Encode.roc
+++ b/crates/compiler/builtins/roc/Encode.roc
@@ -45,31 +45,31 @@ import Num exposing [
 ]
 import Bool exposing [Bool]
 
-Encoder fmt := List U8, fmt -> List U8 where fmt implements EncoderFormatting
+Encoder state fmt := state, fmt -> state where fmt implements EncoderFormatting
 
 Encoding implements
-    toEncoder : val -> Encoder fmt where val implements Encoding, fmt implements EncoderFormatting
+    toEncoder : val -> Encoder state fmt where val implements Encoding, fmt implements EncoderFormatting
 
 EncoderFormatting implements
-    u8 : U8 -> Encoder fmt where fmt implements EncoderFormatting
-    u16 : U16 -> Encoder fmt where fmt implements EncoderFormatting
-    u32 : U32 -> Encoder fmt where fmt implements EncoderFormatting
-    u64 : U64 -> Encoder fmt where fmt implements EncoderFormatting
-    u128 : U128 -> Encoder fmt where fmt implements EncoderFormatting
-    i8 : I8 -> Encoder fmt where fmt implements EncoderFormatting
-    i16 : I16 -> Encoder fmt where fmt implements EncoderFormatting
-    i32 : I32 -> Encoder fmt where fmt implements EncoderFormatting
-    i64 : I64 -> Encoder fmt where fmt implements EncoderFormatting
-    i128 : I128 -> Encoder fmt where fmt implements EncoderFormatting
-    f32 : F32 -> Encoder fmt where fmt implements EncoderFormatting
-    f64 : F64 -> Encoder fmt where fmt implements EncoderFormatting
-    dec : Dec -> Encoder fmt where fmt implements EncoderFormatting
-    bool : Bool -> Encoder fmt where fmt implements EncoderFormatting
-    string : Str -> Encoder fmt where fmt implements EncoderFormatting
-    list : List elem, (elem -> Encoder fmt) -> Encoder fmt where fmt implements EncoderFormatting
-    record : List { key : Str, value : Encoder fmt } -> Encoder fmt where fmt implements EncoderFormatting
-    tuple : List (Encoder fmt) -> Encoder fmt where fmt implements EncoderFormatting
-    tag : Str, List (Encoder fmt) -> Encoder fmt where fmt implements EncoderFormatting
+    u8 : U8 -> Encoder state fmt where fmt implements EncoderFormatting
+    u16 : U16 -> Encoder state fmt where fmt implements EncoderFormatting
+    u32 : U32 -> Encoder state fmt where fmt implements EncoderFormatting
+    u64 : U64 -> Encoder state fmt where fmt implements EncoderFormatting
+    u128 : U128 -> Encoder state fmt where fmt implements EncoderFormatting
+    i8 : I8 -> Encoder state fmt where fmt implements EncoderFormatting
+    i16 : I16 -> Encoder state fmt where fmt implements EncoderFormatting
+    i32 : I32 -> Encoder state fmt where fmt implements EncoderFormatting
+    i64 : I64 -> Encoder state fmt where fmt implements EncoderFormatting
+    i128 : I128 -> Encoder state fmt where fmt implements EncoderFormatting
+    f32 : F32 -> Encoder state fmt where fmt implements EncoderFormatting
+    f64 : F64 -> Encoder state fmt where fmt implements EncoderFormatting
+    dec : Dec -> Encoder state fmt where fmt implements EncoderFormatting
+    bool : Bool -> Encoder state fmt where fmt implements EncoderFormatting
+    string : Str -> Encoder state fmt where fmt implements EncoderFormatting
+    list : List elem, (elem -> Encoder state fmt) -> Encoder state fmt where fmt implements EncoderFormatting
+    record : List { key : Str, value : Encoder state fmt } -> Encoder state fmt where fmt implements EncoderFormatting
+    tuple : List (Encoder state fmt) -> Encoder state fmt where fmt implements EncoderFormatting
+    tag : Str, List (Encoder state fmt) -> Encoder state fmt where fmt implements EncoderFormatting
 
 ## Creates a custom encoder from a given function.
 ##
@@ -83,10 +83,10 @@ EncoderFormatting implements
 ##
 ##     actual == expected
 ## ```
-custom : (List U8, fmt -> List U8) -> Encoder fmt where fmt implements EncoderFormatting
+custom : (state, fmt -> state) -> Encoder state fmt where fmt implements EncoderFormatting
 custom = \encoder -> @Encoder encoder
 
-appendWith : List U8, Encoder fmt, fmt -> List U8 where fmt implements EncoderFormatting
+appendWith : state, Encoder state fmt, fmt -> state where fmt implements EncoderFormatting
 appendWith = \lst, @Encoder doEncoding, fmt -> doEncoding lst fmt
 
 ## Appends the encoded representation of a value to an existing list of bytes.
@@ -98,7 +98,7 @@ appendWith = \lst, @Encoder doEncoding, fmt -> doEncoding lst fmt
 ##
 ##     actual == expected
 ## ```
-append : List U8, val, fmt -> List U8 where val implements Encoding, fmt implements EncoderFormatting
+append : state, val, fmt -> state where val implements Encoding, fmt implements EncoderFormatting
 append = \lst, val, fmt -> appendWith lst (toEncoder val) fmt
 
 ## Encodes a value to a list of bytes (`List U8`) according to the specified format.