diff --git a/tests/extractors/__init__.py b/tests/extractors/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/extractors/test_categories.py b/tests/extractors/test_categories.py
index 4ae0a12..13f7f26 100644
--- a/tests/extractors/test_categories.py
+++ b/tests/extractors/test_categories.py
@@ -19,7 +19,7 @@ def categories_df(categories_df_and_registry):
 
 
 def test_equals_expected(datadir, categories_df):
-    expected_df = pd.read_pickle(datadir / "categories_df_out.pickle")
+    expected_df = pd.read_json(datadir / "categories_df_out.json", orient="table")
 
     assert categories_df.equals(expected_df)
 
diff --git a/tests/extractors/test_categories/categories_df_out.json b/tests/extractors/test_categories/categories_df_out.json
new file mode 100644
index 0000000..91342c2
--- /dev/null
+++ b/tests/extractors/test_categories/categories_df_out.json
@@ -0,0 +1,74 @@
+{
+  "schema":{
+    "fields":[
+      {
+        "name":"id",
+        "type":"integer"
+      },
+      {
+        "name":"count",
+        "type":"integer"
+      },
+      {
+        "name":"description",
+        "type":"string"
+      },
+      {
+        "name":"link",
+        "type":"string"
+      },
+      {
+        "name":"name",
+        "type":"string"
+      },
+      {
+        "name":"slug",
+        "type":"string"
+      },
+      {
+        "name":"parent",
+        "type":"number"
+      },
+      {
+        "name":"link_locale",
+        "type":"string"
+      }
+    ],
+    "primaryKey":[
+      "id"
+    ],
+    "pandas_version":"1.4.0"
+  },
+  "data":[
+    {
+      "id":1,
+      "count":3,
+      "description":"About Test Category One",
+      "link":"https:\/\/example.org\/test-category-one\/",
+      "name":"Test Category One",
+      "slug":"test-category-one",
+      "parent":null,
+      "link_locale":null
+    },
+    {
+      "id":2,
+      "count":3,
+      "description":"About Test Category Two",
+      "link":"https:\/\/example.org\/fr\/test-category-two\/",
+      "name":"Test Category Two",
+      "slug":"test-category-two",
+      "parent":null,
+      "link_locale":"fr"
+    },
+    {
+      "id":3,
+      "count":3,
+      "description":"About Test Category Three",
+      "link":"https:\/\/example.org\/fr\/test-category-three\/",
+      "name":"Test Category Three",
+      "slug":"test-category-three",
+      "parent":2.0,
+      "link_locale":"fr"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/tests/extractors/test_categories/categories_df_out.pickle b/tests/extractors/test_categories/categories_df_out.pickle
deleted file mode 100644
index ad87721..0000000
Binary files a/tests/extractors/test_categories/categories_df_out.pickle and /dev/null differ
diff --git a/tests/extractors/test_tags.py b/tests/extractors/test_tags.py
index a9ede29..04a29ae 100644
--- a/tests/extractors/test_tags.py
+++ b/tests/extractors/test_tags.py
@@ -18,7 +18,7 @@ def tags_df(tags_df_and_registry):
 
 
 def test_equals_expected(datadir, tags_df):
-    expected_df = pd.read_pickle(datadir / "tags_df_out.pickle")
+    expected_df = pd.read_json(datadir / "tags_df_out.json", orient="table")
 
     assert tags_df.equals(expected_df)
 
diff --git a/tests/extractors/test_tags/tags_df_out.json b/tests/extractors/test_tags/tags_df_out.json
new file mode 100644
index 0000000..56b4e4d
--- /dev/null
+++ b/tests/extractors/test_tags/tags_df_out.json
@@ -0,0 +1,67 @@
+{
+  "schema":{
+    "fields":[
+      {
+        "name":"id",
+        "type":"integer"
+      },
+      {
+        "name":"count",
+        "type":"integer"
+      },
+      {
+        "name":"description",
+        "type":"string"
+      },
+      {
+        "name":"link",
+        "type":"string"
+      },
+      {
+        "name":"name",
+        "type":"string"
+      },
+      {
+        "name":"slug",
+        "type":"string"
+      },
+      {
+        "name":"link_locale",
+        "type":"string"
+      }
+    ],
+    "primaryKey":[
+      "id"
+    ],
+    "pandas_version":"1.4.0"
+  },
+  "data":[
+    {
+      "id":1,
+      "count":3,
+      "description":"About Test Tag One",
+      "link":"https:\/\/example.org\/tag\/test-tag-one\/",
+      "name":"Test Tag One",
+      "slug":"test-tag-one",
+      "link_locale":null
+    },
+    {
+      "id":2,
+      "count":3,
+      "description":"About Test Tag Two",
+      "link":"https:\/\/example.org\/fr\/test-tag-two\/",
+      "name":"Test Tag Two",
+      "slug":"test-tag-two",
+      "link_locale":"fr"
+    },
+    {
+      "id":3,
+      "count":3,
+      "description":"About Test Tag Three",
+      "link":"https:\/\/example.org\/fr\/tag\/test-tag-three\/",
+      "name":"Test Tag Three",
+      "slug":"test-tag-three",
+      "link_locale":"fr"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/tests/extractors/test_tags/tags_df_out.pickle b/tests/extractors/test_tags/tags_df_out.pickle
deleted file mode 100644
index 75f252a..0000000
Binary files a/tests/extractors/test_tags/tags_df_out.pickle and /dev/null differ
diff --git a/tests/extractors/test_users.py b/tests/extractors/test_users.py
index 6fffde8..9d219ba 100644
--- a/tests/extractors/test_users.py
+++ b/tests/extractors/test_users.py
@@ -9,5 +9,5 @@ def users_df(datadir):
 
 
 def test_user_load(datadir, users_df):
-    expected_df = pd.read_pickle(datadir / "users_df_out.pickle")
+    expected_df = pd.read_json(datadir / "users_df_out.json", orient="table")
     assert users_df.equals(expected_df)
diff --git a/tests/extractors/test_users/users_df_out.json b/tests/extractors/test_users/users_df_out.json
new file mode 100644
index 0000000..0dc4de3
--- /dev/null
+++ b/tests/extractors/test_users/users_df_out.json
@@ -0,0 +1,49 @@
+{
+  "schema":{
+    "fields":[
+      {
+        "name":"id",
+        "type":"integer"
+      },
+      {
+        "name":"name",
+        "type":"string"
+      },
+      {
+        "name":"url",
+        "type":"string"
+      },
+      {
+        "name":"description",
+        "type":"string"
+      },
+      {
+        "name":"link",
+        "type":"string"
+      },
+      {
+        "name":"slug",
+        "type":"string"
+      },
+      {
+        "name":"avatar",
+        "type":"string"
+      }
+    ],
+    "primaryKey":[
+      "id"
+    ],
+    "pandas_version":"1.4.0"
+  },
+  "data":[
+    {
+      "id":1,
+      "name":"Author1",
+      "url":"https:\/\/author1.gate.ac.uk",
+      "description":"An author",
+      "link":"https:\/\/example.org\/author\/author1\/",
+      "slug":"author1",
+      "avatar":"https:\/\/secure.gravatar.com\/avatar\/f72c502e0d657f363b5f2dc79dd8ceea?s=500&d=mm&r=g"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/tests/extractors/test_users/users_df_out.pickle b/tests/extractors/test_users/users_df_out.pickle
deleted file mode 100644
index ae37bb0..0000000
Binary files a/tests/extractors/test_users/users_df_out.pickle and /dev/null differ