diff --git a/ansiscape/types/sequence_type.py b/ansiscape/types/sequence_type.py
index 33a6b34..bd1534e 100644
--- a/ansiscape/types/sequence_type.py
+++ b/ansiscape/types/sequence_type.py
@@ -9,6 +9,12 @@
 class SequenceType(ABC):
     """A sequence of strings, formatting interpretations and sub-sequences."""
 
+    @abstractmethod
+    def encoded(self) -> str:
+        """
+        Encodes the sequence into a single string with embedded escape codes.
+        """
+
     @abstractmethod
     def extend(self, *parts: SequencePart) -> None:
         """Extends this sequence."""