diff --git a/ffi/serial.nim b/ffi/serial.nim
index d0f3cf8..28ff240 100644
--- a/ffi/serial.nim
+++ b/ffi/serial.nim
@@ -2,6 +2,17 @@ import std/[json, macros, options]
 import results
 import ./codegen/meta
 
+## RawString passes the C string through as-is, with no JSON encoding/decoding.
+## Use this when the C caller provides a value that should not be treated as a
+## JSON-encoded string (e.g. a raw config JSON blob, a multiaddress, an ENR).
+type RawString* = distinct string
+
+proc ffiSerialize*(x: RawString): string =
+  string(x)
+
+proc ffiDeserialize*(s: cstring, _: typedesc[RawString]): Result[RawString, string] =
+  ok(RawString($s))
+
 proc ffiSerialize*(x: string): string =
   $(%*x)