diff --git a/spacy/string_tools.pxd b/spacy/string_tools.pxd
index 7f27c19e5..a034bf230 100644
--- a/spacy/string_tools.pxd
+++ b/spacy/string_tools.pxd
@@ -1,3 +1,7 @@
+cpdef bytes to_bytes(unicode string)
+
+cpdef unicode from_bytes(bytes string)
+
 cpdef unicode substr(unicode string, int start, int end, size_t length)
 
 cdef bint is_whitespace(Py_UNICODE c)
diff --git a/spacy/string_tools.pyx b/spacy/string_tools.pyx
index 2f199766f..f1854a0b0 100644
--- a/spacy/string_tools.pyx
+++ b/spacy/string_tools.pyx
@@ -1,6 +1,14 @@
 # cython: profile=True
 
 
+cpdef bytes to_bytes(unicode string):
+    return string.encode('utf8')
+
+
+cpdef unicode from_bytes(bytes string):
+    return string.decode('utf8')
+
+
 cpdef unicode substr(unicode string, int start, int end, size_t length):
     if end >= length:
         end = -1