diff --git a/.bumpversion.toml b/.bumpversion.toml
index b5d3fc21..fcac6615 100644
--- a/.bumpversion.toml
+++ b/.bumpversion.toml
@@ -1,5 +1,5 @@
 [tool.bumpversion]
-current_version = "1.19.0+260822"
+current_version = "1.19.0+260829"
 parse = "(?P<major>\\d+)\\.(?P<minor>\\d+)\\.(?P<patch>\\d+)\\+(?P<build>\\d+)"
 serialize = ["{major}.{minor}.{patch}+{build}"]
 search = "{current_version}"
diff --git a/pyproject.toml b/pyproject.toml
index 08a87cd3..14ab0ad3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "rasenmaeher_api"
-version = "1.19.0+260822"
+version = "1.19.0+260829"
 description = "python-rasenmaeher-api"
 authors = [
     { name = "Aciid", email = "703382+Aciid@users.noreply.github.com" },
diff --git a/src/rasenmaeher_api/__init__.py b/src/rasenmaeher_api/__init__.py
index 184d5e2c..68ae0b0e 100644
--- a/src/rasenmaeher_api/__init__.py
+++ b/src/rasenmaeher_api/__init__.py
@@ -1,3 +1,3 @@
 """python-rasenmaeher-api"""
 
-__version__ = "1.19.0+260822"  # NOTE Use `bump-my-version` to bump versions correctly
+__version__ = "1.19.0+260829"  # NOTE Use `bump-my-version` to bump versions correctly
diff --git a/src/rasenmaeher_api/productapihelpers.py b/src/rasenmaeher_api/productapihelpers.py
index de8b2133..b1852021 100644
--- a/src/rasenmaeher_api/productapihelpers.py
+++ b/src/rasenmaeher_api/productapihelpers.py
@@ -122,7 +122,11 @@ async def _method_to_product(
     session = await get_session_winit()
     async with session as client:
         try:
-            url = f"{productconf['api']}{url_suffix}"
+            # Normalise the join: every manifest "api" value ends in "/" (see
+            # miniwerk manifests), so a suffix that also starts with one gave
+            # "https://host:4626//api/v1/..." — which Starlette does not route,
+            # so the product 404s and the caller sees only a swallowed None.
+            url = f"{productconf['api'].rstrip('/')}/{url_suffix.lstrip('/')}"
             LOGGER.debug(f"calling {methodname}({url})")
             if data is None:
                 resp = await getattr(client, methodname)(url, timeout=rmconf.integration_api_timeout)
diff --git a/src/rasenmaeher_api/web/api/product/views.py b/src/rasenmaeher_api/web/api/product/views.py
index 9323d5fd..72bc8a9c 100644
--- a/src/rasenmaeher_api/web/api/product/views.py
+++ b/src/rasenmaeher_api/web/api/product/views.py
@@ -168,7 +168,7 @@ async def add_interop(
         raise HTTPException(status_code=500, detail="Manifest does not have products key")
     if tgtproduct not in manifest["products"]:
         raise HTTPException(status_code=404, detail=f"Unknown product {tgtproduct}")
-    resp = await post_to_product(tgtproduct, "/api/v1/interop/add", srcproduct.model_dump(), OperationResultResponse)
+    resp = await post_to_product(tgtproduct, "api/v1/interop/add", srcproduct.model_dump(), OperationResultResponse)
     if resp is None:
         return OperationResultResponse(success=False, error="post_to_product returned None")
     resp = cast(OperationResultResponse, resp)
diff --git a/tests/test_rasenmaeher_api.py b/tests/test_rasenmaeher_api.py
index 3882e13f..062a3464 100644
--- a/tests/test_rasenmaeher_api.py
+++ b/tests/test_rasenmaeher_api.py
@@ -15,7 +15,7 @@
 
 def test_version() -> None:
     """Make sure version matches expected"""
-    assert __version__ == "1.19.0+260822"
+    assert __version__ == "1.19.0+260829"
 
 
 @pytest.mark.asyncio(loop_scope="session")
diff --git a/uv.lock b/uv.lock
index 922ecf51..f25792a9 100644
--- a/uv.lock
+++ b/uv.lock
@@ -2110,7 +2110,7 @@ wheels = [
 
 [[package]]
 name = "rasenmaeher-api"
-version = "1.19.0+260822"
+version = "1.19.0+260829"
 source = { editable = "." }
 dependencies = [
     { name = "aiodns" },