diff --git a/novem/api_ref.py b/novem/api_ref.py
index 66998a2..3af1381 100644
--- a/novem/api_ref.py
+++ b/novem/api_ref.py
@@ -67,6 +67,39 @@ class NovemAuthError(NovemException):
     pass
 
 
+def raise_on_response(r: requests.Response) -> None:
+    """Raise the appropriate ``NovemException`` for a non-ok API response.
+
+    Surfaces the server's ``message`` and any ``rejected`` lines (e.g. the
+    recipient-write reject contract) so callers get a real exception to catch
+    instead of a silent no-op. No-op on a successful response.
+    """
+    if r.ok or r.status_code == 409:
+        return
+
+    try:
+        resp = r.json()
+    except ValueError:
+        resp = {}
+
+    message = resp.get("message") or r.text or f"HTTP {r.status_code}"
+
+    rejected = resp.get("rejected")
+    if rejected:
+        lines = "; ".join(f'{item.get("line")}: {item.get("reason")}' for item in rejected if isinstance(item, dict))
+        if lines:
+            message = f"{message} [{lines}]"
+
+    code = r.status_code
+    if code == 401:
+        raise Novem401(message)
+    if code == 403:
+        raise Novem403(message)
+    if code == 404:
+        raise Novem404(message)
+    raise NovemException(message)
+
+
 class NovemAPI(object):
     """
     Novem API class
diff --git a/novem/exceptions/__init__.py b/novem/exceptions/__init__.py
index a79a7c1..37f8eb2 100644
--- a/novem/exceptions/__init__.py
+++ b/novem/exceptions/__init__.py
@@ -1,3 +1,11 @@
-from ..api_ref import Novem401, Novem403, Novem404, NovemAuthError, NovemException
+from ..api_ref import Novem401, Novem403, Novem404, Novem409, NovemAuthError, NovemException, raise_on_response
 
-__all__ = ["NovemException", "Novem404", "Novem403", "Novem401", "NovemAuthError"]
+__all__ = [
+    "NovemException",
+    "Novem404",
+    "Novem403",
+    "Novem401",
+    "Novem409",
+    "NovemAuthError",
+    "raise_on_response",
+]
diff --git a/novem/group/__init__.py b/novem/group/__init__.py
index 0bbb712..3492ac1 100644
--- a/novem/group/__init__.py
+++ b/novem/group/__init__.py
@@ -1,6 +1,6 @@
 from typing import Any, Optional
 
-from novem.exceptions import Novem403, Novem404
+from novem.exceptions import Novem403, Novem404, raise_on_response
 
 from ..api_ref import NovemAPI
 from .profile import NovemGroupProfile
@@ -147,17 +147,8 @@ def api_create(self, relpath: str) -> None:
             # as creating objects that already exist is not a problem
             return
 
-        # TODO: verify result and raise exception if not ok
         if not r.ok:
-            print(r)
-            print(f"PUT: {path}")
-            print("body")
-            print("---")
-            print(r.text)
-            print("headers")
-            print("---")
-            print(r.headers)
-            print("should raise a general error")
+            raise_on_response(r)
 
     def api_write(self, relpath: str, value: str) -> None:
         """
@@ -180,22 +171,8 @@ def api_write(self, relpath: str, value: str) -> None:
         if r.status_code == 404:
             raise Novem404(path)
 
-        if r.status_code == 403:
-            raise Novem403
-
-        # TODO: verify result and raise exception if not ok
         if not r.ok:
-            print(r)
-            print(f"POST: {path} {value}")
-            print("body")
-            print("---")
-            print(r.text)
-            print(r.status_code)
-            print("headers")
-            print("---")
-            for k, v in r.headers.items():
-                print(f"   {k}: {v}")
-            print("should raise a general error")
+            raise_on_response(r)
 
     @property
     def permissions(self) -> str:
diff --git a/novem/job/__init__.py b/novem/job/__init__.py
index ad94e50..533372f 100644
--- a/novem/job/__init__.py
+++ b/novem/job/__init__.py
@@ -3,7 +3,7 @@
 import sys
 from typing import Any, Dict, List, Optional, Tuple
 
-from novem.exceptions import Novem403, Novem404
+from novem.exceptions import Novem403, Novem404, raise_on_response
 
 from ..api_ref import NovemAPI
 from ..shared import NovemShare
@@ -182,17 +182,8 @@ def api_create(self, relpath: str) -> None:
             # as creating objects that already exist is not a problem
             return
 
-        # TODO: verify result and raise exception if not ok
         if not r.ok:
-            print(r)
-            print(f"PUT: {path}")
-            print("body")
-            print("---")
-            print(r.text)
-            print("headers")
-            print("---")
-            print(r.headers)
-            print("should raise a general error")
+            raise_on_response(r)
 
     def api_write(self, relpath: str, value: str) -> None:
         """
@@ -218,22 +209,8 @@ def api_write(self, relpath: str, value: str) -> None:
         if r.status_code == 404:
             raise Novem404(path)
 
-        if r.status_code == 403:
-            raise Novem403
-
-        # TODO: verify result and raise exception if not ok
         if not r.ok:
-            print(r)
-            print(f"POST: {path} {value}")
-            print("body")
-            print("---")
-            print(r.text)
-            print(r.status_code)
-            print("headers")
-            print("---")
-            for k, v in r.headers.items():
-                print(f"   {k}: {v}")
-            print("should raise a general error")
+            raise_on_response(r)
 
     # chainable utility function for setting values
     def w(self, key: str, value: str) -> Any:
diff --git a/novem/repo/__init__.py b/novem/repo/__init__.py
index 52254d6..d0cc2c5 100644
--- a/novem/repo/__init__.py
+++ b/novem/repo/__init__.py
@@ -1,6 +1,6 @@
 from typing import Any, Optional
 
-from novem.exceptions import Novem403, Novem404
+from novem.exceptions import Novem403, Novem404, raise_on_response
 
 from ..api_ref import NovemAPI
 from ..shared import NovemShare
@@ -144,17 +144,8 @@ def api_create(self, relpath: str) -> None:
             # as creating objects that already exist is not a problem
             return
 
-        # TODO: verify result and raise exception if not ok
         if not r.ok:
-            print(r)
-            print(f"PUT: {path}")
-            print("body")
-            print("---")
-            print(r.text)
-            print("headers")
-            print("---")
-            print(r.headers)
-            print("should raise a general error")
+            raise_on_response(r)
 
     def api_write(self, relpath: str, value: str) -> None:
         """
@@ -177,22 +168,8 @@ def api_write(self, relpath: str, value: str) -> None:
         if r.status_code == 404:
             raise Novem404(path)
 
-        if r.status_code == 403:
-            raise Novem403
-
-        # TODO: verify result and raise exception if not ok
         if not r.ok:
-            print(r)
-            print(f"POST: {path} {value}")
-            print("body")
-            print("---")
-            print(r.text)
-            print(r.status_code)
-            print("headers")
-            print("---")
-            for k, v in r.headers.items():
-                print(f"   {k}: {v}")
-            print("should raise a general error")
+            raise_on_response(r)
 
     # chainable utility function for setting values
     def w(self, key: str, value: str) -> Any:
diff --git a/novem/vis/__init__.py b/novem/vis/__init__.py
index 7a28121..f49bab4 100644
--- a/novem/vis/__init__.py
+++ b/novem/vis/__init__.py
@@ -2,7 +2,7 @@
 import warnings
 from typing import Any, Dict, List, Optional, Tuple
 
-from novem.exceptions import Novem403, Novem404
+from novem.exceptions import Novem403, Novem404, raise_on_response
 
 from ..api_ref import NovemAPI
 from ..shared import NovemShare
@@ -383,17 +383,8 @@ def api_create(self, relpath: str) -> None:
             # as creating objects that already exist is not a problem
             return
 
-        # TODO: verify result and raise exception if not ok
         if not r.ok:
-            print(r)
-            print(f"PUT: {path}")
-            print("body")
-            print("---")
-            print(r.text)
-            print("headers")
-            print("---")
-            print(r.headers)
-            print("should raise a general error")
+            raise_on_response(r)
 
     def api_write(self, relpath: str, value: str) -> None:
         """
@@ -419,22 +410,8 @@ def api_write(self, relpath: str, value: str) -> None:
         if r.status_code == 404:
             raise Novem404(path)
 
-        if r.status_code == 403:
-            raise Novem403
-
-        # TODO: verify result and raise exception if not ok
         if not r.ok:
-            print(r)
-            print(f"POST: {path} {value}")
-            print("body")
-            print("---")
-            print(r.text)
-            print(r.status_code)
-            print("headers")
-            print("---")
-            for k, v in r.headers.items():
-                print(f"   {k}: {v}")
-            print("should raise a general error")
+            raise_on_response(r)
 
     @property
     def log(self) -> None: