diff --git a/pdftables_api/pdftables_api.py b/pdftables_api/pdftables_api.py
index 65e6241..2b5f31d 100644
--- a/pdftables_api/pdftables_api.py
+++ b/pdftables_api/pdftables_api.py
@@ -39,7 +39,7 @@
     '.xlsx': FORMAT_XLSX,
     '.xml': FORMAT_XML,
 }
-
+_STRING_FORMATS = {FORMAT_CSV, FORMAT_XML}
 
 class Client(object):
     def __init__(self, api_key, api_url=_API_URL, timeout=_DEFAULT_TIMEOUT):
@@ -47,44 +47,62 @@ def __init__(self, api_key, api_url=_API_URL, timeout=_DEFAULT_TIMEOUT):
         self.api_url = api_url
         self.timeout = timeout
 
-    def xlsx(self, pdf_path, xlsx_path):
+    def xlsx(self, pdf_path, xlsx_path=None):
         """
         Convenience method to convert PDF to XLSX multiple sheets.
+
+        If xlsx_path is None, returns the output as a byte string.
         """
         return self.xlsx_multiple(pdf_path, xlsx_path)
 
-    def xlsx_single(self, pdf_path, xlsx_path):
+    def xlsx_single(self, pdf_path, xlsx_path=None):
         """
         Convenience method to convert PDF to XLSX single sheet.
+
+        If xlsx_path is None, returns the output as a byte string.
         """
         return self.convert(pdf_path, xlsx_path, out_format=FORMAT_XLSX_SINGLE)
 
-    def xlsx_multiple(self, pdf_path, xlsx_path):
+    def xlsx_multiple(self, pdf_path, xlsx_path=None):
         """
         Convenience method to convert PDF to XLSX multiple sheets.
+
+        If xlsx_path is None, returns the output as a byte string.
         """
         return self.convert(pdf_path, xlsx_path, out_format=FORMAT_XLSX_MULTIPLE)
 
-    def xml(self, pdf_path, xml_path):
+    def xml(self, pdf_path, xml_path=None):
         """
         Convenience method to convert PDF to XML.
+
+        If xml_path is None, returns the output as a string.
         """
         return self.convert(pdf_path, xml_path, out_format=FORMAT_XML)
 
-    def csv(self, pdf_path, csv_path):
+    def csv(self, pdf_path, csv_path=None):
         """
         Convenience method to convert PDF to CSV.
+
+        If csv_path is None, returns the output as a string.
         """
         return self.convert(pdf_path, csv_path, out_format=FORMAT_CSV)
 
-    def convert(self, pdf_path, out_path, out_format=None, query_params=None, **requests_params):
+    def convert(self, pdf_path, out_path=None, out_format=None, query_params=None, **requests_params):
         """
         Convert PDF given by `pdf_path` into `format` at `out_path`.
+
+        If `out_path` is None, returns a string containing the contents, or a
+        bytes for binary output types (e.g, XLSX)
         """
         (out_path, out_format) = Client.ensure_format_ext(out_path, out_format)
         with open(pdf_path, 'rb') as pdf_fo:
             response = self.request(pdf_fo, out_format, query_params,
                                     **requests_params)
+
+            if out_path is None:
+                use_text = out_format in _STRING_FORMATS
+                return response.text if use_text else response.content
+
             with open(out_path, 'wb') as out_fo:
                 copyfileobj(response.raw, out_fo)
 
diff --git a/test/test_pdftables_api.py b/test/test_pdftables_api.py
index 512f07a..9348641 100644
--- a/test/test_pdftables_api.py
+++ b/test/test_pdftables_api.py
@@ -92,6 +92,32 @@ def test_successful_conversion(self):
                     except OSError:
                         pass
 
+    def test_successful_conversion_bytes(self):
+        with requests_mock.mock() as m:
+            m.post('https://pdftables.com/api?key=fake_key', content=b'xlsx output')
+
+            with NamedTemporaryFile(suffix="test.pdf") as tf:
+                filename = tf.name
+                tf.write(b"Hello world")
+                tf.file.close()
+
+                output = Client('fake_key').convert(filename)
+
+                self.assertEqual(b'xlsx output', output)
+
+    def test_successful_conversion_string(self):
+        with requests_mock.mock() as m:
+            m.post('https://pdftables.com/api?key=fake_key', text='csv output')
+
+            with NamedTemporaryFile(suffix="test.pdf") as tf:
+                filename = tf.name
+                tf.write(b"Hello world")
+                tf.file.close()
+
+                output = Client('fake_key').convert(filename, out_format="csv")
+
+                self.assertEqual('csv output', output)
+
     def test_different_api_url(self):
         with requests_mock.mock() as m:
             m.post('http://example.com/api?key=fake_key', text='xlsx output')