diff --git a/aiida_firecrest/transport.py b/aiida_firecrest/transport.py
index 32558fc..ae1a35d 100644
--- a/aiida_firecrest/transport.py
+++ b/aiida_firecrest/transport.py
@@ -116,6 +116,17 @@ class FirecrestTransport(Transport):
                 "callback": validate_positive_number,
             },
         ),
+        (
+            "file_transfer_poll_interval",
+            {
+                "type": float,
+                "default": 0.1,  # TODO what default to choose?
+                "non_interactive_default": True,
+                "prompt": "File transfer poll interval (s)",
+                "help": "Poll interval when waiting for large file transfers.",
+                "callback": validate_positive_number,
+            },
+        ),
     ]
 
     def __init__(
@@ -126,13 +137,17 @@ def __init__(
         client_id: str,
         client_secret: str | Path,
         client_machine: str,
-        small_file_size_mb: float,
+        small_file_size_mb: float = 5.0,
+        file_transfer_poll_interval: float = 0.1,
         # note, machine is provided by default,
         # for the hostname, but we don't use that
         # TODO ideally hostname would not be necessary on a computer
         **kwargs: Any,
     ):
         """Construct a FirecREST transport."""
+        # there is no overhead for "opening" a connection to a REST-API,
+        # but still allow the user to set a safe interval if they really want to
+        kwargs.setdefault("safe_interval", 0)
         super().__init__(**kwargs)  # type: ignore
 
         assert isinstance(url, str), "url must be a string"
@@ -146,12 +161,16 @@ def __init__(
         assert isinstance(
             small_file_size_mb, float
         ), "small_file_size_mb must be a float"
+        assert isinstance(
+            file_transfer_poll_interval, float
+        ), "file_transfer_poll_interval must be a float"
 
         self._machine = client_machine
         self._url = url
         self._token_uri = token_uri
         self._client_id = client_id
         self._small_file_size_bytes = int(small_file_size_mb * 1024 * 1024)
+        self._file_transfer_poll_interval = file_transfer_poll_interval
 
         secret = (
             client_secret.read_text()
@@ -349,9 +368,8 @@ def getfile(
 
                 # this waits for the file to be moved to the staging area
                 # TODO handle the transfer stalling (timeout?) and optimise the polling interval
-                # (and allow configurability?)
                 while down_obj.in_progress:
-                    time.sleep(0.1)
+                    time.sleep(self._file_transfer_poll_interval)
 
                 # this downloads the file from the "staging area"
                 url = down_obj.object_storage_data
@@ -443,9 +461,8 @@ def putfile(
                 up_obj.finish_upload()
                 # this waits for the file in the staging area to be moved to the final location
                 # TODO handle the transfer stalling (timeout?) and optimise the polling interval
-                # (and allow configurability?)
                 while up_obj.in_progress:
-                    time.sleep(0.1)
+                    time.sleep(self._file_transfer_poll_interval)
 
         # TODO use cwd.checksum to confirm upload is not corrupted?