diff --git a/packages/models-library/src/models_library/function_service/demo_units.py b/packages/models-library/src/models_library/function_service/demo_units.py
index 30e6996fc00..6337668cdcf 100644
--- a/packages/models-library/src/models_library/function_service/demo_units.py
+++ b/packages/models-library/src/models_library/function_service/demo_units.py
@@ -5,7 +5,7 @@
 
 def build_input(schema):
     description = schema.pop("description", schema["title"])
-    
+
     return {
         "label": schema["title"],
         "description": description,
@@ -15,11 +15,14 @@ def build_input(schema):
 
 
 # SEE https://github.com/hgrecco/pint/blob/master/pint/default_en.txt
+
 META = ServiceDockerData.parse_obj(
     {
         "integration-version": LATEST_INTEGRATION_VERSION,
         "key": f"{FUNCTION_SERVICE_KEY_PREFIX}/data-iterator/demo-units",
-        "version": "0.1.0",
+        "version": "0.2.0",
+        # CHANGELOG
+        # - 0.2.0: reverted order of first 5 outputs
         "type": ServiceType.BACKEND,
         "name": "Demo Units",
         "description": "Demo that takes base units as inputs and transform them in the outputs",
@@ -100,19 +103,18 @@ def build_input(schema):
             ),
         },
         "outputs": {
-            "length": build_input(
+            "mass": build_input(
                 {
-                    "title": "Distance",
-                    "description": "Distance value converted",
-                    "x_unit": "milli-meter",
+                    "title": "Mass",
+                    "minimum": 0,
+                    "x_unit": "kilo-gram",
                     "type": "number",
                 }
             ),
-            "time": build_input(
+            "luminosity": build_input(
                 {
-                    "title": "Time",
-                    "minimum": 0,
-                    "x_unit": "minute",
+                    "title": "Luminosity",
+                    "x_unit": "candela",
                     "type": "number",
                 }
             ),
@@ -123,18 +125,19 @@ def build_input(schema):
                     "type": "number",
                 }
             ),
-            "luminosity": build_input(
+            "time": build_input(
                 {
-                    "title": "Luminosity",
-                    "x_unit": "candela",
+                    "title": "Time",
+                    "minimum": 0,
+                    "x_unit": "minute",
                     "type": "number",
                 }
             ),
-            "mass": build_input(
+            "length": build_input(
                 {
-                    "title": "Mass",
-                    "minimum": 0,
-                    "x_unit": "kilo-gram",
+                    "title": "Distance",
+                    "description": "Distance value converted",
+                    "x_unit": "milli-meter",
                     "type": "number",
                 }
             ),
diff --git a/packages/models-library/src/models_library/projects_nodes_io.py b/packages/models-library/src/models_library/projects_nodes_io.py
index 3b490d99710..6b4de2cec03 100644
--- a/packages/models-library/src/models_library/projects_nodes_io.py
+++ b/packages/models-library/src/models_library/projects_nodes_io.py
@@ -1,5 +1,9 @@
 """
-    Models used as I/O of Nodes
+    Link models used at i/o port nodes:
+        - Link to files:
+            - Generic: DownloadLink
+            - At Custom Service: SimCoreFileLink, DatCoreFileLink
+        - Link to another port: PortLink
 """
 
 from pathlib import Path
@@ -26,30 +30,46 @@ class PortLink(BaseModel):
     node_uuid: NodeID = Field(
         ...,
         description="The node to get the port output from",
-        example=["da5068e0-8a8d-4fb9-9516-56e5ddaef15b"],
         alias="nodeUuid",
     )
     output: str = Field(
         ...,
         description="The port key in the node given by nodeUuid",
         regex=PROPERTY_KEY_RE,
-        example=["out_2"],
     )
 
     class Config:
         extra = Extra.forbid
+        schema_extra = {
+            "examples": [
+                # minimal
+                {
+                    "nodeUuid": "da5068e0-8a8d-4fb9-9516-56e5ddaef15b",
+                    "output": "out_2",
+                }
+            ],
+        }
 
 
 class DownloadLink(BaseModel):
     """I/O port type to hold a generic download link to a file (e.g. S3 pre-signed link, etc)"""
 
     download_link: AnyUrl = Field(..., alias="downloadLink")
-    label: Optional[str]
+    label: Optional[str] = None
 
     class Config:
         extra = Extra.forbid
+        schema_extra = {
+            "examples": [
+                # minimal
+                {
+                    "downloadLink": "https://fakeimg.pl/250x100/",
+                }
+            ],
+        }
 
 
+## CUSTOM STORAGE SERVICES -----------
 class BaseFileLink(BaseModel):
     """Base class for I/O port types with links to storage services"""
 
@@ -59,23 +79,17 @@ class BaseFileLink(BaseModel):
     store: Union[str, int] = Field(
         ...,
         description="The store identifier: '0' or 0 for simcore S3, '1' or 1 for datcore",
-        examples=["0", 1],
     )
 
     path: str = Field(
         ...,
         regex=r"^.+$",
         description="The path to the file in the storage provider domain",
-        examples=[
-            "N:package:b05739ef-260c-4038-b47d-0240d04b0599",
-            "94453a6a-c8d4-52b3-a22d-ccbf81f8d636/d4442ca4-23fd-5b6b-ba6d-0b75f711c109/y_1D.txt",
-        ],
     )
 
     label: Optional[str] = Field(
         None,
         description="The real file name",
-        examples=["MyFile.txt"],
     )
 
     e_tag: Optional[str] = Field(
@@ -112,9 +126,10 @@ def pre_fill_label_with_filename_ext(cls, v, values):
     class Config:
         extra = Extra.forbid
         schema_extra = {
+            # a project file
             "example": {
                 "store": "0",
-                "path": "api/0a3b2c56-dbcd-4871-b93b-d454b7883f9f/input.txt",
+                "path": "94453a6a-c8d4-52b3-a22d-ccbf81f8d636/0a3b2c56-dbcd-4871-b93b-d454b7883f9f/input.txt",
                 "eTag": "859fda0cb82fc4acb4686510a172d9a9-1",
                 "label": "input.txt",
             },
@@ -123,7 +138,12 @@ class Config:
                 {
                     "store": "0",
                     "path": "api/0a3b2c56-dbcd-4871-b93b-d454b7883f9f/input.txt",
-                }
+                },
+                # w/ store id as int
+                {
+                    "store": 0,
+                    "path": "94453a6a-c8d4-52b3-a22d-ccbf81f8d636/d4442ca4-23fd-5b6b-ba6d-0b75f711c109/y_1D.txt",
+                },
             ],
         }
 
@@ -134,13 +154,11 @@ class DatCoreFileLink(BaseFileLink):
     label: str = Field(
         ...,
         description="The real file name",
-        examples=["MyFile.txt"],
     )
 
     dataset: str = Field(
         ...,
         description="Unique identifier to access the dataset on datcore (REQUIRED for datcore)",
-        example=["N:dataset:f9f5ac51-33ea-4861-8e08-5b4faf655041"],
     )
 
     @validator("store", always=True)
@@ -162,4 +180,17 @@ class Config:
                 "path": "N:package:32df09ba-e8d6-46da-bd54-f696157de6ce",
                 "label": "initial_WTstates",
             },
+            "examples": [
+                # with store id as str
+                {
+                    "store": "1",
+                    "dataset": "N:dataset:ea2325d8-46d7-4fbd-a644-30f6433070b4",
+                    "path": "N:package:32df09ba-e8d6-46da-bd54-f696157de6ce",
+                    "label": "initial_WTstates",
+                },
+            ],
         }
+
+
+# Bundles all model links to a file vs PortLink
+LinkToFileTypes = Union[SimCoreFileLink, DatCoreFileLink, DownloadLink]
diff --git a/packages/models-library/tests/test_projects_pipeline.py b/packages/models-library/tests/test_projects_pipeline.py
index 828e6504ea9..0cbf054eaca 100644
--- a/packages/models-library/tests/test_projects_pipeline.py
+++ b/packages/models-library/tests/test_projects_pipeline.py
@@ -3,16 +3,20 @@
 # pylint:disable=redefined-outer-name
 
 from pprint import pformat
+from typing import Dict, Type
 
 import pytest
 from models_library.projects_pipeline import ComputationTask
+from pydantic import BaseModel
 
 
 @pytest.mark.parametrize(
     "model_cls",
     (ComputationTask,),
 )
-def test_computation_task_model_examples(model_cls, model_cls_examples):
+def test_computation_task_model_examples(
+    model_cls: Type[BaseModel], model_cls_examples: Dict[str, Dict]
+):
     for name, example in model_cls_examples.items():
         print(name, ":", pformat(example))
         model_instance = model_cls(**example)
diff --git a/services/web/server/docker/boot.sh b/services/web/server/docker/boot.sh
index f4b3e530423..4f0762a840d 100755
--- a/services/web/server/docker/boot.sh
+++ b/services/web/server/docker/boot.sh
@@ -29,8 +29,10 @@ elif [ "${SC_BUILD_TARGET}" = "production" ]; then
   APP_CONFIG=server-docker-prod.yaml
 fi
 
+APP_LOG_LEVEL=${WEBSERVER_LOGLEVEL:-${LOG_LEVEL:-${LOGLEVEL}}}
+
 # RUNNING application ----------------------------------------
-echo "$INFO" "Selected config $APP_CONFIG"
+echo "$INFO" "Selected config $APP_CONFIG w/ log-level $APP_LOG_LEVEL"
 
 # NOTE: the number of workers ```(2 x $num_cores) + 1``` is
 # the official recommendation [https://docs.gunicorn.org/en/latest/design.html#how-many-workers]
@@ -44,7 +46,7 @@ if [ "${SC_BOOT_MODE}" = "debug-ptvsd" ]; then
     --worker-class aiohttp.GunicornWebWorker \
     --workers="${WEBSERVER_GUNICORN_WORKERS:-1}" \
     --name="webserver_$(hostname)_$(date +'%Y-%m-%d_%T')_$$" \
-    --log-level="${LOG_LEVEL:-info}" \
+    --log-level="${APP_LOG_LEVEL:-info}" \
     --access-logfile='-' \
     --access-logformat='%a %t "%r" %s %b [%Dus] "%{Referer}i" "%{User-Agent}i"' \
     --reload
@@ -55,7 +57,7 @@ else
     --worker-class aiohttp.GunicornWebWorker \
     --workers="${WEBSERVER_GUNICORN_WORKERS:-1}" \
     --name="webserver_$(hostname)_$(date +'%Y-%m-%d_%T')_$$" \
-    --log-level="${LOG_LEVEL:-warning}" \
+    --log-level="${APP_LOG_LEVEL:-warning}" \
     --access-logfile='-' \
     --access-logformat='%a %t "%r" %s %b [%Dus] "%{Referer}i" "%{User-Agent}i"'
 fi
diff --git a/services/web/server/requirements/_base.in b/services/web/server/requirements/_base.in
index 6ef97fb88e6..0001654f78e 100644
--- a/services/web/server/requirements/_base.in
+++ b/services/web/server/requirements/_base.in
@@ -17,67 +17,42 @@
 --requirement ../../../../packages/service-library/requirements/_aiohttp.in
 
 
-# aiohttp + extensions
-aiohttp
-aiohttp_jinja2
-aiohttp_session[secure]
-aiohttp_security
-aiohttp-swagger[performance]
-gunicorn[setproctitle]
-
-
 # web-sockets
 # From 5.0.0, https://github.com/miguelgrinberg/python-socketio/blob/main/CHANGES.md
 # test_resource_manager.py::test_websocket_resource_management fails because
 # socket_id saved in redis does not correspond to client's sio
 python-socketio~=4.6.1
 
-# postgres db
-aiopg[sa]
-asyncpg
-
-# i/o
-aiofiles
-
-# redis
-aioredis
-aioredlock
-
-# RabbitMQ client
-aio-pika
-
-# email
-aiosmtplib
-jinja_app_loader
-
-
-# data models
-pydantic[email]
-
-# security
-cryptography
-passlib
-
-# json
-orjson
-jsondiff
-json2html
-
-# asyncio debug
-aiodebug
+# SEE services/web/server/tests/unit/isolated/test_utils.py::test_yarl_url_compose_changed_with_latest_release
+yarl<1.6
 
 
-# misc
+aio-pika # RabbitMQ client
+aiodebug # asyncio debug
+aiofiles # i/o
+aiohttp
+aiohttp_jinja2
+aiohttp_security
+aiohttp_session[secure]
+aiohttp-swagger[performance]
+aiopg[sa] # db
+aioredis # redis
+aioredlock # redis
+aiosmtplib # email
+asyncpg # db
 change_case
+cryptography # security
 expiringdict
+gunicorn[setproctitle]
+jinja_app_loader # email
+json2html
+jsondiff
+openpyxl # excel
+orjson  # json
+parfive  # excel
+passlib
+pint # units
+pydantic[email] # models
+python-magic # excel
 semantic_version
 tenacity
-
-# import/export excel
-parfive
-openpyxl
-python-magic
-
-
-# SEE services/web/server/tests/unit/isolated/test_utils.py::test_yarl_url_compose_changed_with_latest_release
-yarl<1.6
diff --git a/services/web/server/requirements/_base.txt b/services/web/server/requirements/_base.txt
index 0790af9df8e..b04143a064d 100644
--- a/services/web/server/requirements/_base.txt
+++ b/services/web/server/requirements/_base.txt
@@ -191,12 +191,16 @@ openpyxl==3.0.7
     # via -r requirements/_base.in
 orjson==3.5.3
     # via -r requirements/_base.in
+packaging==21.3
+    # via pint
 pamqp==2.3.0
     # via aiormq
 parfive==1.5.1
     # via -r requirements/_base.in
 passlib==1.7.4
     # via -r requirements/_base.in
+pint==0.18
+    # via -r requirements/_base.in
 prometheus-client==0.12.0
     # via -r requirements/../../../../packages/service-library/requirements/_aiohttp.in
 psycopg2-binary==2.9.1
@@ -225,6 +229,8 @@ pyinstrument==3.4.2
     #   -r requirements/../../../../packages/service-library/requirements/_base.in
 pyinstrument-cext==0.2.4
     # via pyinstrument
+pyparsing==3.0.7
+    # via packaging
 pyrsistent==0.18.0
     # via jsonschema
 python-engineio==3.14.2
diff --git a/services/web/server/requirements/_test.txt b/services/web/server/requirements/_test.txt
index c4e714de956..bd416327db6 100644
--- a/services/web/server/requirements/_test.txt
+++ b/services/web/server/requirements/_test.txt
@@ -159,6 +159,7 @@ openapi-spec-validator==0.3.1
     #   -r requirements/_test.in
 packaging==21.3
     # via
+    #   -c requirements/_base.txt
     #   pytest
     #   pytest-sugar
 paramiko==2.8.0
@@ -185,8 +186,10 @@ pylint==2.12.1
     # via -r requirements/_test.in
 pynacl==1.4.0
     # via paramiko
-pyparsing==3.0.6
-    # via packaging
+pyparsing==3.0.7
+    # via
+    #   -c requirements/_base.txt
+    #   packaging
 pyrsistent==0.18.0
     # via
     #   -c requirements/_base.txt
diff --git a/services/web/server/src/simcore_service_webserver/catalog.py b/services/web/server/src/simcore_service_webserver/catalog.py
index 46ee55328bc..b86939f08fb 100644
--- a/services/web/server/src/simcore_service_webserver/catalog.py
+++ b/services/web/server/src/simcore_service_webserver/catalog.py
@@ -6,13 +6,14 @@
 
 from aiohttp import web
 from aiohttp.web_routedef import RouteDef
+from pint import UnitRegistry
 from servicelib.aiohttp.application_setup import ModuleCategory, app_module_setup
 from servicelib.aiohttp.rest_routing import iter_path_operations
 
 from . import catalog_handlers
 from ._constants import APP_OPENAPI_SPECS_KEY
 from .catalog_client import get_services_for_user_in_product, is_service_responsive
-from .catalog_handlers_utils import reverse_proxy_handler
+from .catalog_utils import reverse_proxy_handler
 
 logger = logging.getLogger(__name__)
 
@@ -48,6 +49,9 @@ def setup_catalog(app: web.Application):
     # reverse proxy to catalog's API
     app.router.add_routes(routes)
 
+    # prepares units registry
+    app[UnitRegistry.__name__] = UnitRegistry()
+
 
 __all__: Tuple[str] = (
     "get_services_for_user_in_product",
diff --git a/services/web/server/src/simcore_service_webserver/catalog_handlers.py b/services/web/server/src/simcore_service_webserver/catalog_handlers.py
index 1bd1075c226..1a1b5abe771 100644
--- a/services/web/server/src/simcore_service_webserver/catalog_handlers.py
+++ b/services/web/server/src/simcore_service_webserver/catalog_handlers.py
@@ -6,21 +6,23 @@
 from aiohttp import web
 from aiohttp.web import Request, RouteTableDef
 from models_library.services import ServiceInput, ServiceOutput
+from pint import UnitRegistry
 from pydantic import ValidationError
 
 from . import catalog_client
 from ._constants import RQ_PRODUCT_KEY
 from ._meta import api_version_prefix
 from .catalog_models import (
-    ServiceInputApiOut,
+    ServiceInputGet,
     ServiceInputKey,
     ServiceKey,
-    ServiceOutputApiOut,
+    ServiceOutputGet,
     ServiceOutputKey,
     ServiceVersion,
     json_dumps,
     replace_service_input_outputs,
 )
+from .catalog_utils import can_connect
 from .login.decorators import RQT_USERID_KEY, login_required
 from .rest_constants import RESPONSE_MODEL_POLICY
 from .security_decorators import permission_required
@@ -44,6 +46,7 @@ class _RequestContext:
     app: web.Application
     user_id: int
     product_name: str
+    unit_registry: UnitRegistry
 
     @classmethod
     def create(cls, request: Request) -> "_RequestContext":
@@ -51,6 +54,7 @@ def create(cls, request: Request) -> "_RequestContext":
             app=request.app,
             user_id=request[RQT_USERID_KEY],
             product_name=request[RQ_PRODUCT_KEY],
+            unit_registry=request.app[UnitRegistry.__name__],
         )
 
 
@@ -280,56 +284,14 @@ async def get_compatible_outputs_given_target_input_handler(request: Request):
 #
 
 
-def can_connect(
-    from_output: ServiceOutput, to_input: ServiceInput, *, strict: bool = False
-) -> bool:
-    # FIXME: can_connect is a very very draft version
-
-    # compatible units
-    ok = from_output.unit == to_input.unit
-    if ok:
-        # compatible types
-        # FIXME: see mimetypes examples in property_type
-        #
-        #   "pattern": "^(number|integer|boolean|string|data:([^/\\s,]+/[^/\\s,]+|\\[[^/\\s,]+/[^/\\s,]+(,[^/\\s]+/[^/,\\s]+)*\\]))$",
-        #   "description": "data type expected on this input glob matching for data type is allowed",
-        #   "examples": [
-        #     "number",
-        #     "boolean",
-        #     "data:*/*",
-        #     "data:text/*",
-        #     "data:[image/jpeg,image/png]",
-        #     "data:application/json",
-        #     "data:application/json;schema=https://my-schema/not/really/schema.json",
-        #     "data:application/vnd.ms-excel",
-        #     "data:text/plain",
-        #     "data:application/hdf5",
-        #     "data:application/edu.ucdavis@ceclancy.xyz"
-        #
-        ok = from_output.property_type == to_input.property_type
-        if not ok:
-            ok = (
-                # data:  -> data:*/*
-                to_input.property_type == "data:*/*"
-                and from_output.property_type.startswith("data:")
-            )
-
-            if not strict:
-                # NOTE: by default, this is allowed in the UI but not in a more strict plausibility check
-                # data:*/*  -> data:
-                ok |= (
-                    from_output.property_type == "data:*/*"
-                    and to_input.property_type.startswith("data:")
-                )
-    return ok
-
-
 async def list_services(ctx: _RequestContext):
     services = await catalog_client.get_services_for_user_in_product(
         ctx.app, ctx.user_id, ctx.product_name, only_key_versions=False
     )
     for service in services:
-        replace_service_input_outputs(service, **RESPONSE_MODEL_POLICY)
+        replace_service_input_outputs(
+            service, unit_registry=ctx.unit_registry, **RESPONSE_MODEL_POLICY
+        )
     return services
 
 
@@ -339,7 +301,9 @@ async def get_service(
     service = await catalog_client.get_service(
         ctx.app, ctx.user_id, service_key, service_version, ctx.product_name
     )
-    replace_service_input_outputs(service, **RESPONSE_MODEL_POLICY)
+    replace_service_input_outputs(
+        service, unit_registry=ctx.unit_registry, **RESPONSE_MODEL_POLICY
+    )
     return service
 
 
@@ -357,21 +321,24 @@ async def update_service(
         ctx.product_name,
         update_data,
     )
-    replace_service_input_outputs(service, **RESPONSE_MODEL_POLICY)
+    replace_service_input_outputs(
+        service, unit_registry=ctx.unit_registry, **RESPONSE_MODEL_POLICY
+    )
     return service
 
 
 async def list_service_inputs(
     service_key: ServiceKey, service_version: ServiceVersion, ctx: _RequestContext
-) -> List[ServiceOutputApiOut]:
+) -> ServiceOutputGet:
 
     service = await catalog_client.get_service(
         ctx.app, ctx.user_id, service_key, service_version, ctx.product_name
     )
-
     inputs = []
     for input_key in service["inputs"].keys():
-        service_input = ServiceInputApiOut.from_catalog_service(service, input_key)
+        service_input = ServiceInputGet.from_catalog_service_api_model(
+            service, input_key
+        )
         inputs.append(service_input)
     return inputs
 
@@ -381,12 +348,12 @@ async def get_service_input(
     service_version: ServiceVersion,
     input_key: ServiceInputKey,
     ctx: _RequestContext,
-) -> ServiceInputApiOut:
+) -> ServiceInputGet:
 
     service = await catalog_client.get_service(
         ctx.app, ctx.user_id, service_key, service_version, ctx.product_name
     )
-    service_input = ServiceInputApiOut.from_catalog_service(service, input_key)
+    service_input = ServiceInputGet.from_catalog_service_api_model(service, input_key)
 
     return service_input
 
@@ -427,7 +394,7 @@ def iter_service_inputs() -> Iterator[Tuple[ServiceInputKey, ServiceInput]]:
     # check
     matches = []
     for key_id, to_input in iter_service_inputs():
-        if can_connect(from_output, to_input):
+        if can_connect(from_output, to_input, units_registry=ctx.unit_registry):
             matches.append(key_id)
 
     return matches
@@ -437,14 +404,16 @@ async def list_service_outputs(
     service_key: ServiceKey,
     service_version: ServiceVersion,
     ctx: _RequestContext,
-) -> List[ServiceOutputApiOut]:
+) -> List[ServiceOutputGet]:
     service = await catalog_client.get_service(
         ctx.app, ctx.user_id, service_key, service_version, ctx.product_name
     )
 
     outputs = []
     for output_key in service["outputs"].keys():
-        service_output = ServiceOutputApiOut.from_catalog_service(service, output_key)
+        service_output = ServiceOutputGet.from_catalog_service_api_model(
+            service, output_key
+        )
         outputs.append(service_output)
     return outputs
 
@@ -454,11 +423,13 @@ async def get_service_output(
     service_version: ServiceVersion,
     output_key: ServiceOutputKey,
     ctx: _RequestContext,
-) -> ServiceOutputApiOut:
+) -> ServiceOutputGet:
     service = await catalog_client.get_service(
         ctx.app, ctx.user_id, service_key, service_version, ctx.product_name
     )
-    service_output = ServiceOutputApiOut.from_catalog_service(service, output_key)
+    service_output = ServiceOutputGet.from_catalog_service_api_model(
+        service, output_key
+    )
 
     return service_output
 
@@ -492,7 +463,7 @@ def iter_service_outputs() -> Iterator[Tuple[ServiceOutputKey, ServiceOutput]]:
     # check
     matches = []
     for key_id, from_output in iter_service_outputs():
-        if can_connect(from_output, to_input):
+        if can_connect(from_output, to_input, units_registry=ctx.unit_registry):
             matches.append(key_id)
 
     return matches
diff --git a/services/web/server/src/simcore_service_webserver/catalog_handlers_utils.py b/services/web/server/src/simcore_service_webserver/catalog_handlers_utils.py
deleted file mode 100644
index 131ea6736ba..00000000000
--- a/services/web/server/src/simcore_service_webserver/catalog_handlers_utils.py
+++ /dev/null
@@ -1,54 +0,0 @@
-import logging
-from typing import Optional
-
-from aiohttp import web
-from yarl import URL
-
-from . import catalog_client
-from ._constants import RQ_PRODUCT_KEY, X_PRODUCT_NAME_HEADER
-from .catalog_client import to_backend_service
-from .catalog_settings import get_plugin_settings
-from .login.decorators import RQT_USERID_KEY, login_required
-from .security_decorators import permission_required
-
-logger = logging.getLogger(__name__)
-
-
-@login_required
-@permission_required("services.catalog.*")
-async def reverse_proxy_handler(request: web.Request) -> web.Response:
-    """
-        - Adds auth layer
-        - Adds access layer
-        - Forwards request to catalog service
-
-    SEE https://gist.github.com/barrachri/32f865c4705f27e75d3b8530180589fb
-    """
-    user_id = request[RQT_USERID_KEY]
-    settings = get_plugin_settings(request.app)
-
-    # path & queries
-    backend_url = to_backend_service(
-        request.rel_url,
-        URL(settings.base_url),
-        settings.CATALOG_VTAG,
-    )
-    # FIXME: hack
-    if "/services" in backend_url.path:
-        backend_url = backend_url.update_query({"user_id": user_id})
-    logger.debug("Redirecting '%s' -> '%s'", request.url, backend_url)
-
-    # body
-    raw: Optional[bytes] = None
-    if request.can_read_body:
-        raw = await request.read()
-
-    # injects product discovered by middleware in headers
-    fwd_headers = request.headers.copy()
-    product_name = request[RQ_PRODUCT_KEY]
-    fwd_headers.update({X_PRODUCT_NAME_HEADER: product_name})
-
-    # forward request
-    return await catalog_client.make_request_and_envelope_response(
-        request.app, request.method, backend_url, fwd_headers, raw
-    )
diff --git a/services/web/server/src/simcore_service_webserver/catalog_models.py b/services/web/server/src/simcore_service_webserver/catalog_models.py
index df498b72d1d..b7af15161a3 100644
--- a/services/web/server/src/simcore_service_webserver/catalog_models.py
+++ b/services/web/server/src/simcore_service_webserver/catalog_models.py
@@ -8,9 +8,11 @@
     ServiceInput,
     ServiceOutput,
 )
+from pint import UnitRegistry
 from pydantic import Extra, Field, constr
 from pydantic.main import BaseModel
 
+from .catalog_utils import UnitHtmlFormat, get_html_formatted_unit
 from .utils import snake_to_camel
 
 ServiceKey = constr(regex=KEY_RE)
@@ -19,24 +21,6 @@
 ServiceOutputKey = PropertyName
 
 
-# TODO: will be replaced by pynt functionality
-FAKE_UNIT_TO_FORMATS = {"SECOND": ("s", "seconds"), "METER": ("m", "meters")}
-
-
-class CannotFormatUnitError(ValueError):
-    """Either unit is not provided or is invalid or is not registered"""
-
-
-def get_formatted_unit(data: dict):
-    try:
-        unit = data["unit"]
-        if unit is None:
-            raise CannotFormatUnitError()
-        return FAKE_UNIT_TO_FORMATS[unit.upper()]
-    except KeyError as err:
-        raise CannotFormatUnitError() from err
-
-
 def json_dumps(v, *, default=None) -> str:
     # orjson.dumps returns bytes, to match standard json.dumps we need to decode
     return orjson.dumps(v, default=default).decode()
@@ -56,10 +40,12 @@ def json_dumps(v, *, default=None) -> str:
 # TODO: reduce to a minimum returned input/output models (ask OM)
 class _BaseCommonApiExtension(BaseModel):
     unit_long: Optional[str] = Field(
-        None, description="Long name of the unit, if available"
+        None,
+        description="Long name of the unit for display (html-compatible), if available",
     )
     unit_short: Optional[str] = Field(
-        None, description="Short name for the unit, if available"
+        None,
+        description="Short name for the unit for display (html-compatible), if available",
     )
 
     class Config:
@@ -69,7 +55,7 @@ class Config:
         json_dumps = json_dumps
 
 
-class ServiceInputApiOut(ServiceInput, _BaseCommonApiExtension):
+class ServiceInputGet(ServiceInput, _BaseCommonApiExtension):
     key_id: ServiceInputKey = Field(
         ..., description="Unique name identifier for this input"
     )
@@ -87,20 +73,48 @@ class Config(_BaseCommonApiExtension.Config):
                 "keyId": "input_2",
                 "unitLong": "seconds",
                 "unitShort": "sec",
-            }
+            },
+            "examples": [
+                # uses content-schema
+                {
+                    "label": "Acceleration",
+                    "description": "acceleration with units",
+                    "type": "ref_contentSchema",
+                    "contentSchema": {
+                        "title": "Acceleration",
+                        "type": "number",
+                        "x_unit": "m/s**2",
+                    },
+                    "keyId": "input_1",
+                    "unitLong": "meter/second<sup>3</sup>",
+                    "unitShort": "m/s<sup>3</sup>",
+                }
+            ],
         }
 
     @classmethod
-    def from_catalog_service(cls, service: Dict[str, Any], input_key: ServiceInputKey):
+    def from_catalog_service_api_model(
+        cls,
+        service: Dict[str, Any],
+        input_key: ServiceInputKey,
+        ureg: Optional[UnitRegistry] = None,
+    ):
         data = service["inputs"][input_key]
-        try:
-            ushort, ulong = get_formatted_unit(data)
-            return cls(keyId=input_key, unitLong=ulong, unitShort=ushort, **data)
-        except CannotFormatUnitError:
-            return cls(keyId=input_key, **data)
+        port = cls(keyId=input_key, **data)  # validated!
+        unit_html: UnitHtmlFormat
+
+        if ureg and (unit_html := get_html_formatted_unit(port, ureg)):
+            # we know data is ok since it was validated above
+            return cls.construct(
+                keyId=input_key,
+                unitLong=unit_html.long,
+                unitShort=unit_html.short,
+                **data,
+            )
+        return port
 
 
-class ServiceOutputApiOut(ServiceOutput, _BaseCommonApiExtension):
+class ServiceOutputGet(ServiceOutput, _BaseCommonApiExtension):
     key_id: ServiceOutputKey = Field(
         ..., description="Unique name identifier for this input"
     )
@@ -120,21 +134,30 @@ class Config(_BaseCommonApiExtension.Config):
         }
 
     @classmethod
-    def from_catalog_service(
-        cls, service: Dict[str, Any], output_key: ServiceOutputKey
+    def from_catalog_service_api_model(
+        cls,
+        service: Dict[str, Any],
+        output_key: ServiceOutputKey,
+        ureg: Optional[UnitRegistry] = None,
     ):
         data = service["outputs"][output_key]
+        # NOTE: prunes invalid field that might have remained in database
+        # TODO: remove from root and remove this cleanup operation
+        if "defaultValue" in data:
+            data.pop("defaultValue")
 
-        try:
-            # NOTE: prunes invalid field that might have remained in database
-            # TODO: remove from root and remove this cleanup operation
-            if "defaultValue" in data:
-                data.pop("defaultValue")
+        port = cls(keyId=output_key, **data)  # validated
 
-            ushort, ulong = get_formatted_unit(data)
-            return cls(keyId=output_key, unitLong=ulong, unitShort=ushort, **data)
-        except CannotFormatUnitError:
-            return cls(keyId=output_key, **data)
+        unit_html: UnitHtmlFormat
+        if ureg and (unit_html := get_html_formatted_unit(port, ureg)):
+            # we know data is ok since it was validated above
+            return cls.construct(
+                keyId=output_key,
+                unitLong=unit_html.long,
+                unitShort=unit_html.short,
+                **data,
+            )
+        return port
 
 
 #######################
@@ -142,14 +165,23 @@ def from_catalog_service(
 #
 
 
-def replace_service_input_outputs(service: Dict[str, Any], **export_options):
+def replace_service_input_outputs(
+    service: Dict[str, Any],
+    *,
+    unit_registry: Optional[UnitRegistry] = None,
+    **export_options,
+):
     """Thin wrapper to replace i/o ports in returned service model"""
     # This is a fast solution until proper models are available for the web API
 
     for input_key in service["inputs"]:
-        new_input = ServiceInputApiOut.from_catalog_service(service, input_key)
+        new_input = ServiceInputGet.from_catalog_service_api_model(
+            service, input_key, unit_registry
+        )
         service["inputs"][input_key] = new_input.dict(**export_options)
 
     for output_key in service["outputs"]:
-        new_output = ServiceOutputApiOut.from_catalog_service(service, output_key)
+        new_output = ServiceOutputGet.from_catalog_service_api_model(
+            service, output_key, unit_registry
+        )
         service["outputs"][output_key] = new_output.dict(**export_options)
diff --git a/services/web/server/src/simcore_service_webserver/catalog_utils.py b/services/web/server/src/simcore_service_webserver/catalog_utils.py
new file mode 100644
index 00000000000..bab64ce5d02
--- /dev/null
+++ b/services/web/server/src/simcore_service_webserver/catalog_utils.py
@@ -0,0 +1,177 @@
+import logging
+from dataclasses import dataclass
+from typing import Optional
+
+from aiohttp import web
+from models_library.services import BaseServiceIOModel, ServiceInput, ServiceOutput
+from pint import PintError, UnitRegistry
+from yarl import URL
+
+from . import catalog_client
+from ._constants import RQ_PRODUCT_KEY, X_PRODUCT_NAME_HEADER
+from .catalog_client import to_backend_service
+from .catalog_settings import get_plugin_settings
+from .login.decorators import RQT_USERID_KEY, login_required
+from .security_decorators import permission_required
+
+logger = logging.getLogger(__name__)
+
+
+@login_required
+@permission_required("services.catalog.*")
+async def reverse_proxy_handler(request: web.Request) -> web.Response:
+    """
+        - Adds auth layer
+        - Adds access layer
+        - Forwards request to catalog service
+
+    SEE https://gist.github.com/barrachri/32f865c4705f27e75d3b8530180589fb
+    """
+    user_id = request[RQT_USERID_KEY]
+    settings = get_plugin_settings(request.app)
+
+    # path & queries
+    backend_url = to_backend_service(
+        request.rel_url,
+        URL(settings.base_url),
+        settings.CATALOG_VTAG,
+    )
+    # FIXME: hack
+    if "/services" in backend_url.path:
+        backend_url = backend_url.update_query({"user_id": user_id})
+    logger.debug("Redirecting '%s' -> '%s'", request.url, backend_url)
+
+    # body
+    raw: Optional[bytes] = None
+    if request.can_read_body:
+        raw = await request.read()
+
+    # injects product discovered by middleware in headers
+    fwd_headers = request.headers.copy()
+    product_name = request[RQ_PRODUCT_KEY]
+    fwd_headers.update({X_PRODUCT_NAME_HEADER: product_name})
+
+    # forward request
+    return await catalog_client.make_request_and_envelope_response(
+        request.app, request.method, backend_url, fwd_headers, raw
+    )
+
+
+##  MODELS UTILS ---------------------------------
+
+
+def _get_unit_name(port: BaseServiceIOModel) -> str:
+    unit = port.unit
+    if port.property_type == "ref_contentSchema":
+        assert port.content_schema is not None  # nosec
+        unit = port.content_schema.get("x_unit", unit)
+        if unit:
+            # TODO: Review this convention under dev: x_units
+            # has a special format for prefix. tmp direct replace here
+            unit = unit.replace("-", "")
+        elif port.content_schema["type"] in ("object", "array"):
+            # these objects might have unit in its fields
+            raise NotImplementedError
+    return unit
+
+
+def _get_type_name(port: BaseServiceIOModel) -> str:
+    _type = port.property_type
+    if port.property_type == "ref_contentSchema":
+        assert port.content_schema is not None  # nosec
+        _type = port.content_schema["type"]
+    return _type
+
+
+@dataclass
+class UnitHtmlFormat:
+    short: str
+    long: str
+
+
+def get_html_formatted_unit(
+    port: BaseServiceIOModel, ureg: UnitRegistry
+) -> Optional[UnitHtmlFormat]:
+    try:
+        unit_name = _get_unit_name(port)
+        if unit_name is None:
+            return None
+
+        q = ureg.Quantity(unit_name)
+        return UnitHtmlFormat(short=f"{q.units:~H}", long=f"{q.units:H}")
+    except (PintError, NotImplementedError):
+        return None
+
+
+## PORT COMPATIBILITY ---------------------------------
+
+
+def _can_convert_units(from_unit: str, to_unit: str, ureg: UnitRegistry) -> bool:
+    assert from_unit  # nosec
+    assert to_unit  # nosec
+
+    # TODO: optimize by caching?  ureg already caches?
+    # TODO: symmetric
+    try:
+        return ureg.Quantity(from_unit).check(to_unit)
+    except (TypeError, PintError):
+        return False
+
+
+def can_connect(
+    from_output: ServiceOutput,
+    to_input: ServiceInput,
+    units_registry: UnitRegistry,
+) -> bool:
+    """Checks compatibility between ports.
+
+    This check IS PERMISSIVE and is used for checks in the UI where one needs to give some "flexibility" since:
+    - has to be a fast evaluation
+    - there are no error messages when check fails
+    - some configurations might need several UI steps to be valid
+
+    For more strict checks use the "strict" variant
+    """
+    # types check
+    from_type = _get_type_name(from_output)
+    to_type = _get_type_name(to_input)
+
+    ok = (
+        from_type == to_type
+        or (
+            # data:  -> data:*/*
+            to_type == "data:*/*"
+            and from_type.startswith("data:")
+        )
+        or (
+            # NOTE: by default, this is allowed in the UI but not in a more strict plausibility check
+            # data:*/*  -> data:
+            from_type == "data:*/*"
+            and to_type.startswith("data:")
+        )
+    )
+
+    if any(t in ("object", "array") for t in (from_type, to_type)):
+        # Not Implemented but this if e.g. from_type == to_type that should be the answer
+        # TODO: from_type subset of to_type is the right way resolve this check
+        return ok
+
+    # types units
+    if ok:
+        try:
+            from_unit = _get_unit_name(from_output)
+            to_unit = _get_unit_name(to_input)
+        except NotImplementedError:
+            return ok
+
+        ok = ok and (
+            from_unit == to_unit
+            # unitless -> *
+            or from_unit is None
+            # * -> unitless
+            or to_unit is None
+            # from_unit -> unit
+            or _can_convert_units(from_unit, to_unit, units_registry)
+        )
+
+    return ok
diff --git a/services/web/server/tests/unit/isolated/test_catalog_handlers.py b/services/web/server/tests/unit/isolated/test_catalog_handlers.py
deleted file mode 100644
index d1fd071f94c..00000000000
--- a/services/web/server/tests/unit/isolated/test_catalog_handlers.py
+++ /dev/null
@@ -1,41 +0,0 @@
-from models_library.services import ServiceInput, ServiceOutput
-from simcore_service_webserver.catalog_handlers import can_connect
-
-
-def test_can_connect():
-    # Reproduces https://github.com/ITISFoundation/osparc-issues/issues/442
-    file_picker_outfile = {
-        "displayOrder": 2,
-        "label": "File Picker",
-        "description": "Picker",
-        "type": "data:*/*",
-    }
-
-    input_sleeper_input_1 = {
-        "displayOrder": 1,
-        "label": "Sleeper",
-        "description": "sleeper input file",
-        "type": "data:text/plain",
-    }
-
-    # data:*/* -> data:text/plain
-    assert can_connect(
-        from_output=ServiceOutput.parse_obj(file_picker_outfile),
-        to_input=ServiceInput.parse_obj(input_sleeper_input_1),
-    )
-    assert not can_connect(
-        from_output=ServiceOutput.parse_obj(file_picker_outfile),
-        to_input=ServiceInput.parse_obj(input_sleeper_input_1),
-        strict=True,
-    )
-
-    # data:text/plain  -> data:*/*
-    assert can_connect(
-        from_output=ServiceOutput.parse_obj(input_sleeper_input_1),
-        to_input=ServiceInput.parse_obj(file_picker_outfile),
-    )
-    assert can_connect(
-        from_output=ServiceOutput.parse_obj(input_sleeper_input_1),
-        to_input=ServiceInput.parse_obj(file_picker_outfile),
-        strict=True,
-    )
diff --git a/services/web/server/tests/unit/isolated/test_catalog_models.py b/services/web/server/tests/unit/isolated/test_catalog_models.py
index bdc30b9e544..c9e78449db3 100644
--- a/services/web/server/tests/unit/isolated/test_catalog_models.py
+++ b/services/web/server/tests/unit/isolated/test_catalog_models.py
@@ -1,29 +1,38 @@
-# pylint:disable=unused-argument
-# pylint:disable=redefined-outer-name
-# pylint:disable=no-name-in-module
-
+# pylint: disable=redefined-outer-name
+# pylint: disable=unused-argument
+# pylint: disable=unused-variable
 
 import json
 from copy import deepcopy
 from pprint import pformat
+from typing import Any, Dict, Mapping, Type
 
 import pytest
+from pint import UnitRegistry
+from pydantic import BaseModel
 from simcore_service_webserver.catalog_handlers import RESPONSE_MODEL_POLICY
 from simcore_service_webserver.catalog_models import (
-    ServiceInputApiOut,
-    ServiceOutputApiOut,
+    ServiceInputGet,
+    ServiceOutputGet,
     replace_service_input_outputs,
 )
 
 
+@pytest.fixture(scope="module")
+def unit_registry():
+    return UnitRegistry()
+
+
 @pytest.mark.parametrize(
     "model_cls",
     (
-        ServiceInputApiOut,
-        ServiceOutputApiOut,
+        ServiceInputGet,
+        ServiceOutputGet,
     ),
 )
-def test_webserver_catalog_api_models(model_cls, model_cls_examples):
+def test_webserver_catalog_api_models(
+    model_cls: Type[BaseModel], model_cls_examples: Dict[str, Mapping[str, Any]]
+):
     for name, example in model_cls_examples.items():
         print(name, ":", pformat(example))
         model_instance = model_cls(**example)
@@ -34,7 +43,7 @@ def test_webserver_catalog_api_models(model_cls, model_cls_examples):
         assert model_cls(**data) == model_instance
 
 
-def test_from_catalog_to_webapi_service():
+def test_from_catalog_to_webapi_service(unit_registry: UnitRegistry):
 
     # Taken from services/catalog/src/simcore_service_catalog/models/schemas/services.py on Feb.2021
     catalog_service = {
@@ -73,7 +82,7 @@ def test_from_catalog_to_webapi_service():
             "outFile": {
                 "displayOrder": 0,
                 "label": "File",
-                "unit": "second",
+                "unit": "sec",
                 "description": "Chosen File",
                 "type": "data:*/*",
                 "fileToKeyMap": None,
@@ -85,14 +94,16 @@ def test_from_catalog_to_webapi_service():
     }
 
     webapi_service = deepcopy(catalog_service)
-    replace_service_input_outputs(webapi_service, **RESPONSE_MODEL_POLICY)
+    replace_service_input_outputs(
+        webapi_service, unit_registry=unit_registry, **RESPONSE_MODEL_POLICY
+    )
 
     print(json.dumps(webapi_service, indent=2))
 
     # If units are defined, I want unitShort and unitLong
-    assert webapi_service["outputs"]["outFile"]["unit"] is "second"
-    assert webapi_service["outputs"]["outFile"]["unitShort"] is "s"
-    assert webapi_service["outputs"]["outFile"]["unitLong"] is "seconds"
+    assert webapi_service["outputs"]["outFile"]["unit"] == "sec"
+    assert webapi_service["outputs"]["outFile"]["unitShort"] == "s"
+    assert webapi_service["outputs"]["outFile"]["unitLong"] == "second"
 
     # if units are NOT defined => must NOT set Long/Short units
     fields = set(webapi_service["inputs"]["uno"].keys())
diff --git a/services/web/server/tests/unit/isolated/test_catalog_utils.py b/services/web/server/tests/unit/isolated/test_catalog_utils.py
new file mode 100644
index 00000000000..01da0148a8e
--- /dev/null
+++ b/services/web/server/tests/unit/isolated/test_catalog_utils.py
@@ -0,0 +1,216 @@
+# pylint: disable=redefined-outer-name
+# pylint: disable=unused-argument
+# pylint: disable=unused-variable
+
+import itertools
+from typing import Any, Dict
+
+import pytest
+from models_library.function_service import demo_units
+from models_library.services import ServiceInput, ServiceOutput
+from pint import UnitRegistry
+from pydantic import Field, create_model
+from simcore_service_webserver.catalog_utils import can_connect
+
+# HELPERS ----------
+
+
+def create_port_data(schema: Dict[str, Any]):
+    description = schema.pop("description", schema["title"])
+
+    return {
+        "label": schema["title"],
+        "description": description,
+        "type": "ref_contentSchema",
+        "contentSchema": schema,
+    }
+
+
+def upgrade_port_data(old_port) -> Dict[str, Any]:
+    _type = old_port["type"]
+    if _type in ("number", "integer", "string"):
+        # creates schema from old data
+        title = old_port["label"].upper()
+        field_kwargs = {"description": old_port["description"]}
+        if unit := old_port.get("unit"):
+            field_kwargs["x_unit"] = unit
+        python_type = {"number": float, "integer": int, "string": str}
+        schema = create_model(
+            title, __root__=(python_type[_type], Field(..., **field_kwargs))
+        ).schema_json(indent=1)
+        return create_port_data(schema)
+    return old_port
+
+
+# FIXTURES -----------------
+
+
+@pytest.fixture(scope="module")
+def unit_registry():
+    return UnitRegistry()
+
+
+# TESTS -----------------
+
+
+def test_can_connect_for_gh_osparc_issues_442(unit_registry: UnitRegistry):
+    # Reproduces https://github.com/ITISFoundation/osparc-issues/issues/442
+    file_picker_outfile = {
+        "displayOrder": 2,
+        "label": "File Picker",
+        "description": "Picker",
+        "type": "data:*/*",
+    }
+
+    input_sleeper_input_1 = {
+        "displayOrder": 1,
+        "label": "Sleeper",
+        "description": "sleeper input file",
+        "type": "data:text/plain",
+    }
+
+    # data:*/* -> data:text/plain
+    assert can_connect(
+        from_output=ServiceOutput.parse_obj(file_picker_outfile),
+        to_input=ServiceInput.parse_obj(input_sleeper_input_1),
+        units_registry=unit_registry,
+    )
+
+    # data:text/plain  -> data:*/*
+    assert can_connect(
+        from_output=ServiceOutput.parse_obj(input_sleeper_input_1),
+        to_input=ServiceInput.parse_obj(file_picker_outfile),
+        units_registry=unit_registry,
+    )
+
+
+PORTS_WITH_UNITS = [
+    {
+        "label": "port_W/O_old",
+        "description": "output w/o unit old format",
+        "type": "integer",
+    },
+    create_port_data(
+        {
+            "title": "port-W/O",
+            "description": "output w/o unit",
+            "type": "integer",
+        }
+    ),
+]
+
+PORTS_WITHOUT_UNITS = [
+    {
+        "label": "port_W/_old",
+        "description": "port w/ unit old format",
+        "type": "integer",
+        "unit": "m",  # <---
+    },
+    create_port_data(
+        {
+            "title": "port-W/",
+            "description": "port w/ unit",
+            "type": "integer",
+            "x_unit": "cm",  # <---
+        }
+    ),
+]
+
+
+@pytest.mark.parametrize(
+    "port_without_unit, port_with_unit",
+    itertools.product(PORTS_WITHOUT_UNITS, PORTS_WITH_UNITS),
+    ids=lambda l: l["label"],
+)
+def test_can_connect_no_units_with_units(
+    port_without_unit, port_with_unit, unit_registry: UnitRegistry
+):
+    # w/o -> w
+    assert can_connect(
+        from_output=ServiceOutput.parse_obj(port_without_unit),
+        to_input=ServiceInput.parse_obj(port_with_unit),
+        units_registry=unit_registry,
+    )
+
+    # w -> w/o
+    assert can_connect(
+        from_output=ServiceOutput.parse_obj(port_with_unit),
+        to_input=ServiceInput.parse_obj(port_without_unit),
+        units_registry=unit_registry,
+    )
+
+
+@pytest.mark.parametrize(
+    "from_unit, to_unit, are_compatible",
+    [
+        ("cm", "mm", True),
+        ("m", "cm", True),
+        ("cm", "miles", True),
+        ("foot", "cm", True),
+        ("cm", "degrees", False),
+        ("cm", None, True),
+        (None, "cm", True),
+    ],
+)
+def test_units_compatible(
+    from_unit, to_unit, are_compatible, unit_registry: UnitRegistry
+):
+    #
+    # TODO: does it make sense to have a string or bool with x_unit??
+    #
+
+    from_port = create_port_data(
+        {
+            "title": "src",
+            "description": "source port",
+            "type": "number",
+            "x_unit": from_unit,
+        }
+    )
+    to_port = create_port_data(
+        {
+            "title": "dst",
+            "description": "destination port",
+            "type": "number",
+            "x_unit": to_unit,
+        }
+    )
+
+    assert (
+        can_connect(
+            from_output=ServiceOutput.parse_obj(from_port),
+            to_input=ServiceInput.parse_obj(to_port),
+            units_registry=unit_registry,
+        )
+        == are_compatible
+    )
+
+
+@pytest.mark.parametrize(
+    "from_port,to_port",
+    itertools.product(
+        demo_units.META.outputs.values(), demo_units.META.inputs.values()
+    ),
+    ids=lambda p: p.label,
+)
+def test_can_connect_with_units(
+    from_port: ServiceOutput, to_port: ServiceInput, unit_registry: UnitRegistry
+):
+    # WARNING: assumes the following convention for the fixture data:
+    #   - two ports are compatible if they have the same title
+    #
+    # NOTE: this assumption will probably break when the demo_units service
+    # is modified. At that point, please create a fixture in this test-suite
+    # and copy&paste inputs/outputs above
+    are_compatible = (
+        from_port.content_schema["title"] == to_port.content_schema["title"]
+    )
+
+    assert (
+        can_connect(
+            from_output=from_port,
+            to_input=to_port,
+            units_registry=unit_registry,
+        )
+        == are_compatible
+    )