diff --git a/artiq/compiler/builtins.py b/artiq/compiler/builtins.py
index 3e82f955f..9965f5284 100644
--- a/artiq/compiler/builtins.py
+++ b/artiq/compiler/builtins.py
@@ -67,6 +67,10 @@ class TStr(types.TMono):
     def __init__(self):
         super().__init__("str")
 
+class TBytes(types.TMono):
+    def __init__(self):
+        super().__init__("bytes")
+
 class TList(types.TMono):
     def __init__(self, elt=None):
         if elt is None:
@@ -137,6 +141,9 @@ def fn_float():
 def fn_str():
     return types.TConstructor(TStr())
 
+def fn_bytes():
+    return types.TConstructor(TBytes())
+
 def fn_list():
     return types.TConstructor(TList())
 
@@ -236,6 +243,9 @@ def is_float(typ):
 def is_str(typ):
     return types.is_mono(typ, "str")
 
+def is_bytes(typ):
+    return types.is_mono(typ, "bytes")
+
 def is_numeric(typ):
     typ = typ.find()
     return isinstance(typ, types.TMono) and \
@@ -254,7 +264,12 @@ def is_array(typ, elt=None):
         return types.is_mono(typ, "array")
 
 def is_listish(typ, elt=None):
-    return is_list(typ, elt) or is_array(typ, elt) or (elt is None and is_str(typ))
+    if is_list(typ, elt) or is_array(typ, elt):
+        return True
+    elif elt is None:
+        return is_str(typ) or is_bytes(typ)
+    else:
+        return False
 
 def is_range(typ, elt=None):
     if elt is not None:
@@ -277,7 +292,7 @@ def is_iterable(typ):
 def get_iterable_elt(typ):
     if is_iterable(typ):
         return typ.find()["elt"].find()
-    elif is_str(typ):
+    elif is_str(typ) or is_bytes(typ):
         return TInt(types.TValue(8))
     else:
         assert False
diff --git a/artiq/compiler/embedding.py b/artiq/compiler/embedding.py
index b2fd51061..052a5d737 100644
--- a/artiq/compiler/embedding.py
+++ b/artiq/compiler/embedding.py
@@ -200,6 +200,9 @@ class ASTSynthesizer:
         elif isinstance(value, str):
             return asttyped.StrT(s=value, ctx=None, type=builtins.TStr(),
                                  loc=self._add(repr(value)))
+        elif isinstance(value, bytes):
+            return asttyped.StrT(s=value, ctx=None, type=builtins.TBytes(),
+                                 loc=self._add(repr(value)))
         elif isinstance(value, list):
             begin_loc = self._add("[")
             elts = []
diff --git a/artiq/compiler/prelude.py b/artiq/compiler/prelude.py
index f50e4f2fa..f451b8a62 100644
--- a/artiq/compiler/prelude.py
+++ b/artiq/compiler/prelude.py
@@ -11,6 +11,8 @@ def globals():
         "bool":                 builtins.fn_bool(),
         "int":                  builtins.fn_int(),
         "float":                builtins.fn_float(),
+        "str":                  builtins.fn_str(),
+        "bytes":                builtins.fn_bytes(),
         "list":                 builtins.fn_list(),
         "array":                builtins.fn_array(),
         "range":                builtins.fn_range(),
diff --git a/artiq/compiler/transforms/asttyped_rewriter.py b/artiq/compiler/transforms/asttyped_rewriter.py
index 3c840673e..4c3112be6 100644
--- a/artiq/compiler/transforms/asttyped_rewriter.py
+++ b/artiq/compiler/transforms/asttyped_rewriter.py
@@ -331,8 +331,13 @@ class ASTTypedRewriter(algorithm.Transformer):
                              n=node.n, loc=node.loc)
 
     def visit_Str(self, node):
-        return asttyped.StrT(type=builtins.TStr(),
-                             s=node.s,
+        if isinstance(node.s, str):
+            typ = builtins.TStr()
+        elif isinstance(node.s, bytes):
+            typ = builtins.TBytes()
+        else:
+            assert False
+        return asttyped.StrT(type=typ, s=node.s,
                              begin_loc=node.begin_loc, end_loc=node.end_loc, loc=node.loc)
 
     def visit_Name(self, node):
diff --git a/artiq/compiler/transforms/llvm_ir_generator.py b/artiq/compiler/transforms/llvm_ir_generator.py
index 835cf976b..0bb73ef05 100644
--- a/artiq/compiler/transforms/llvm_ir_generator.py
+++ b/artiq/compiler/transforms/llvm_ir_generator.py
@@ -1054,7 +1054,7 @@ class LLVMIRGenerator:
                 lloperand = self.map(operand)
                 if i == 0 and insn.op == "printf" or i == 1 and insn.op == "rtio_log":
                     lloperands.append(self.llbuilder.extract_value(lloperand, 0))
-                elif builtins.is_str(operand.type):
+                elif builtins.is_str(operand.type) or builtins.is_bytes(operand.type):
                     lloperands.append(self.llbuilder.extract_value(lloperand, 1))
                     lloperands.append(self.llbuilder.extract_value(lloperand, 0))
                 else:
@@ -1434,7 +1434,7 @@ class LLVMIRGenerator:
         elif builtins.is_float(typ):
             assert isinstance(value, float), fail_msg
             return ll.Constant(llty, value)
-        elif builtins.is_str(typ):
+        elif builtins.is_str(typ) or builtins.is_bytes(typ):
             assert isinstance(value, (str, bytes)), fail_msg
             if isinstance(value, str):
                 as_bytes = value.encode("utf-8")
diff --git a/artiq/test/lit/inferencer/unify.py b/artiq/test/lit/inferencer/unify.py
index bb7fd9241..5ccbc6b70 100644
--- a/artiq/test/lit/inferencer/unify.py
+++ b/artiq/test/lit/inferencer/unify.py
@@ -57,6 +57,9 @@ lambda x, y=1: x
 k = "x"
 # CHECK-L: k:str
 
+ka = b"x"
+# CHECK-L: ka:bytes
+
 l = array([1])
 # CHECK-L: l:numpy.array(elt=numpy.int?)