diff --git a/elx/catalog.py b/elx/catalog.py
index d09d7ce..d4e1caa 100644
--- a/elx/catalog.py
+++ b/elx/catalog.py
@@ -7,6 +7,7 @@ class Stream(BaseModel):
     stream: str = Field(alias="tap_stream_id")
     table_name: Optional[str] = None
     replication_method: Optional[str] = "FULL_TABLE"
+    replication_key: Optional[str] = None
     key_properties: List[str]
     stream_schema: dict = Field(alias="schema")
     is_view: Optional[bool] = False
diff --git a/tests/conftest.py b/tests/conftest.py
index 746ec38..067a7c7 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,5 +1,5 @@
 from fixtures.singer import singer
-from fixtures.tap import tap
+from fixtures.tap import tap, tap_incremental
 from fixtures.target import target
 from fixtures.runner import runner
 from fixtures.state import state_manager
diff --git a/tests/fixtures/tap.py b/tests/fixtures/tap.py
index c16b870..5780457 100644
--- a/tests/fixtures/tap.py
+++ b/tests/fixtures/tap.py
@@ -20,3 +20,15 @@ def tap() -> Generator[Tap, None, None]:
             ],
         },
     )
+
+
+@pytest.fixture(scope="session")
+def tap_incremental() -> Generator[Tap, None, None]:
+    """
+    Return a Tap instance for the  executable with an incremental stream.
+    """
+    yield Tap(
+        executable="tap-mock-incremental",
+        spec="git+https://github.com/quantile-taps/tap-mock-incremental.git",
+        config={},
+    )
diff --git a/tests/test_elx/test_catalog.py b/tests/test_elx/test_catalog.py
index b5f2d1c..ab4b026 100644
--- a/tests/test_elx/test_catalog.py
+++ b/tests/test_elx/test_catalog.py
@@ -7,6 +7,7 @@
         {
             "tap_stream_id": "animals",
             "replication_method": "FULL_TABLE",
+            "replication_key": None,
             "table_name": None,
             "is_view": False,
             "key_properties": [],
@@ -56,6 +57,54 @@
     ]
 }
 
+INCREMENTAL_CATALOG = {
+    "streams": [
+        {
+            "tap_stream_id": "users",
+            "replication_method": "INCREMENTAL",
+            "replication_key": "updated_at",
+            "table_name": None,
+            "is_view": False,
+            "key_properties": ["id"],
+            "schema": {
+                "properties": {
+                    "id": {"type": ["string", "null"]},
+                    "name": {"type": ["string", "null"]},
+                    "updated_at": {
+                        "format": "date-time",
+                        "type": ["string", "null"],
+                    },
+                },
+                "type": "object",
+            },
+            "metadata": [
+                {
+                    "breadcrumb": ["properties", "id"],
+                    "metadata": {"inclusion": "automatic"},
+                },
+                {
+                    "breadcrumb": ["properties", "name"],
+                    "metadata": {"inclusion": "available"},
+                },
+                {
+                    "breadcrumb": ["properties", "updated_at"],
+                    "metadata": {"inclusion": "automatic"},
+                },
+                {
+                    "breadcrumb": [],
+                    "metadata": {
+                        "inclusion": "available",
+                        "selected": True,
+                        "selected-by-default": True,
+                        "table-key-properties": ["id"],
+                        "valid-replication-keys": ["updated_at"],
+                    },
+                },
+            ],
+        }
+    ]
+}
+
 
 def test_catalog(tap: Tap):
     """
@@ -103,3 +152,49 @@ def test_catalog_deselect_property(tap: Tap):
     catalog_dict = catalog.dict(by_alias=True)
 
     assert catalog_dict["streams"][0]["metadata"][0]["metadata"]["selected"] == False
+
+
+def test_catalog_replication_method(tap_incremental: Tap):
+    """If we have an incremental stream, the replication_method in the catalog should be `INCREMENTAL`."""
+    catalog_dict = tap_incremental.catalog.dict(by_alias=True)
+
+    assert (
+        catalog_dict["streams"][0]["replication_method"]
+        == INCREMENTAL_CATALOG["streams"][0]["replication_method"]
+    )
+
+
+def test_catalog_replication_key(tap_incremental: Tap):
+    """If we have an incremental stream, the catalog should have a `replication_key`."""
+    catalog_dict = tap_incremental.catalog.dict(by_alias=True)
+
+    assert (
+        catalog_dict["streams"][0]["replication_key"]
+        == INCREMENTAL_CATALOG["streams"][0]["replication_key"]
+    )
+
+
+def test_catalog_valid_replication_keys(tap_incremental: Tap):
+    """
+    If we have an incremental stream, the catalog should have a metadata breadcrumb for the incremental
+    stream containing the key: `valid-replication-keys`.
+
+    This key should be associated with a list containing the fields that could be used as replication keys.
+    For example, the metadata breadcrumb of the stream should look as follows if `updated_at` is its replication_key.
+
+    "metadata": {
+        "inclusion": "available",
+        "selected": True,
+        "selected-by-default": True,
+        "table-key-properties": ["id"],
+        "valid-replication-keys": ["updated_at"],
+    }
+    """
+    catalog_dict = tap_incremental.catalog.dict(by_alias=True)
+
+    replication_keys = catalog_dict["streams"][0]["metadata"][-1]["metadata"].get(
+        "valid-replication-keys", None
+    )
+
+    # Checks that value of `valid-replication-keys` equals to the replication-key
+    assert replication_keys == [INCREMENTAL_CATALOG["streams"][0]["replication_key"]]