diff --git a/application/cratedb-toolkit/test_io.py b/application/cratedb-toolkit/test_io.py
index efb727dc..dbe57303 100644
--- a/application/cratedb-toolkit/test_io.py
+++ b/application/cratedb-toolkit/test_io.py
@@ -134,6 +134,12 @@ def test_ctk_load_table_mongodb_json(drop_testing_tables):
             progress=GitProgressPrinter(),
         )
 
+        # The `countries-big.json` file contains bogus characters.
+        countries_big_path = datasets_path / "countries-big.json"
+        payload = countries_big_path.read_text()
+        payload = payload.replace("\ufeff", "")
+        countries_big_path.write_text(payload)
+
     # Invoke data transfer.
     command = f"""
 ctk load table \
diff --git a/application/cratedb-toolkit/zyp-mongodb-json-files.yaml b/application/cratedb-toolkit/zyp-mongodb-json-files.yaml
index 31605164..6cb5b459 100644
--- a/application/cratedb-toolkit/zyp-mongodb-json-files.yaml
+++ b/application/cratedb-toolkit/zyp-mongodb-json-files.yaml
@@ -38,11 +38,78 @@
 meta:
   type: zyp-project
   version: 1
+
 collections:
-- address:
-    container: datasets
-    name: companies
-  pre:
-    rules:
-    - expression: .[] |= del(.image.available_sizes, .screenshots[].available_sizes)
-      type: jq
+
+  - address:
+      container: datasets
+      name: books
+    pre:
+      rules:
+        - expression: .[] |= (._id |= tostring)
+          type: jq
+
+  - address:
+      container: datasets
+      name: city_inspections
+    pre:
+      rules:
+        - expression: |
+            .[] |= (
+              select(true)
+              | .address.number |= numbers
+              | .address.zip |= numbers
+              | .certificate_number |= tostring
+            )
+          type: jq
+
+  - address:
+      container: datasets
+      name: companies
+    pre:
+      rules:
+        - expression: |
+            .[] |= (
+              select(true)
+              |= del(.image.available_sizes, .screenshots[].available_sizes)
+              | .created_at |= strings
+              | .updated_at |= strings
+            )
+          type: jq
+
+  - address:
+      container: datasets
+      name: countries-big
+    pre:
+      rules:
+        - expression: .[] |= (.ISO |= tostring)
+          type: jq
+
+  - address:
+      container: datasets
+      name: products
+    pre:
+      rules:
+        - expression: |
+            .[] |= (
+              select(true)
+              | if (.for) then .for |= to_array end
+              | if (.type) then .type |= to_array end
+              | if (.limits.data.n) then .limits.data.n |= tostring end
+              | if (.limits.sms.n) then .limits.sms.n |= tostring end
+              | if (.limits.voice.n) then .limits.voice.n |= tostring end
+            )
+          type: jq
+
+  - address:
+      container: datasets
+      name: restaurant
+    pre:
+      rules:
+        - expression: |
+            .[] |= (
+              select(true)
+              | .rating |= tostring
+              | .type |= to_array
+            )
+          type: jq