diff --git a/app/apps/api/fields/__init__.py b/app/apps/api/fields/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/app/apps/api/fields/transactions.py b/app/apps/api/fields/transactions.py
new file mode 100644
index 0000000..0225648
--- /dev/null
+++ b/app/apps/api/fields/transactions.py
@@ -0,0 +1,69 @@
+from drf_spectacular.types import OpenApiTypes
+from drf_spectacular.utils import extend_schema_field
+from rest_framework import serializers
+
+from apps.transactions.models import TransactionCategory, TransactionTag
+
+
+@extend_schema_field(
+    {
+        "oneOf": [{"type": "string"}, {"type": "integer"}],
+        "description": "TransactionCategory ID or name. If the name doesn't exist, a new one will be created",
+    }
+)
+class TransactionCategoryField(serializers.Field):
+    def to_representation(self, value):
+        return {"id": value.id, "name": value.name}
+
+    def to_internal_value(self, data):
+        if isinstance(data, int):
+            try:
+                return TransactionCategory.objects.get(pk=data)
+            except TransactionCategory.DoesNotExist:
+                raise serializers.ValidationError(
+                    "Category with this ID does not exist."
+                )
+        elif isinstance(data, str):
+            category, created = TransactionCategory.objects.get_or_create(name=data)
+            return category
+        raise serializers.ValidationError(
+            "Invalid category data. Provide an ID or name."
+        )
+
+    @staticmethod
+    def get_schema():
+        return {
+            "type": "array",
+            "items": {"type": "string", "description": "TransactionTag ID or name"},
+        }
+
+
+@extend_schema_field(
+    {
+        "type": "array",
+        "items": {"oneOf": [{"type": "string"}, {"type": "integer"}]},
+        "description": "TransactionTag ID or name. If the name doesn't exist, a new one will be created",
+    }
+)
+class TransactionTagField(serializers.Field):
+    def to_representation(self, value):
+        return [{"id": tag.id, "name": tag.name} for tag in value.all()]
+
+    def to_internal_value(self, data):
+        tags = []
+        for item in data:
+            if isinstance(item, int):
+                try:
+                    tag = TransactionTag.objects.get(pk=item)
+                except TransactionTag.DoesNotExist:
+                    raise serializers.ValidationError(
+                        f"Tag with ID {item} does not exist."
+                    )
+            elif isinstance(item, str):
+                tag, created = TransactionTag.objects.get_or_create(name=item)
+            else:
+                raise serializers.ValidationError(
+                    "Invalid tag data. Provide an ID or name."
+                )
+            tags.append(tag)
+        return tags
diff --git a/app/apps/api/serializers/transactions.py b/app/apps/api/serializers/transactions.py
index 24c7504..137e849 100644
--- a/app/apps/api/serializers/transactions.py
+++ b/app/apps/api/serializers/transactions.py
@@ -1,7 +1,10 @@
+from django.utils.translation import gettext_lazy as _
+
 from rest_framework import serializers
 from rest_framework.permissions import IsAuthenticated
 
 from apps.accounts.models import Account
+from apps.api.fields.transactions import TransactionTagField, TransactionCategoryField
 from apps.api.serializers.accounts import AccountSerializer
 from apps.transactions.models import (
     Transaction,
@@ -37,8 +40,9 @@ class InstallmentPlanSerializer(serializers.ModelSerializer):
 
 
 class TransactionSerializer(serializers.ModelSerializer):
-    category_name = serializers.CharField(source="category.name", read_only=True)
-    tags = TransactionTagSerializer(many=True, read_only=True)
+    category = TransactionCategoryField(required=False)
+    tags = TransactionTagField(required=False)
+
     exchanged_amount = serializers.SerializerMethodField()
 
     # For read operations (GET)
@@ -49,11 +53,45 @@ class TransactionSerializer(serializers.ModelSerializer):
         queryset=Account.objects.all(), source="account", write_only=True
     )
 
+    reference_date = serializers.DateField(required=False)
+
     permission_classes = [IsAuthenticated]
 
     class Meta:
         model = Transaction
         fields = "__all__"
+        read_only_fields = [
+            "id",
+            "installment_plan",
+            "recurring_transaction",
+            "installment_id",
+        ]
+
+    def validate(self, data):
+        if "date" in data and "reference_date" not in data:
+            data["reference_date"] = data["date"].replace(day=1)
+        elif "reference_date" in data:
+            data["reference_date"] = data["reference_date"].replace(day=1)
+        else:
+            raise serializers.ValidationError(
+                _("Either 'date' or 'reference_date' must be provided.")
+            )
+        return data
+
+    def create(self, validated_data):
+        tags = validated_data.pop("tags", [])
+        transaction = Transaction.objects.create(**validated_data)
+        transaction.tags.set(tags)
+        return transaction
+
+    def update(self, instance, validated_data):
+        tags = validated_data.pop("tags", None)
+        for attr, value in validated_data.items():
+            setattr(instance, attr, value)
+        instance.save()
+        if tags is not None:
+            instance.tags.set(tags)
+        return instance
 
     @staticmethod
     def get_exchanged_amount(obj):
diff --git a/app/apps/transactions/forms.py b/app/apps/transactions/forms.py
index 354e1b0..137215c 100644
--- a/app/apps/transactions/forms.py
+++ b/app/apps/transactions/forms.py
@@ -62,19 +62,6 @@ class TransactionForm(forms.ModelForm):
             "notes": forms.Textarea(attrs={"rows": 3}),
             "account": TomSelect(),
         }
-        # labels = {
-        #     "tags": mark_safe('<i class="fa-solid fa-hashtag me-1"></i>' + _("Tags")),
-        #     "category": mark_safe(
-        #         '<i class="fa-solid fa-icons me-1"></i>' + _("Category")
-        #     ),
-        #     "notes": mark_safe(
-        #         '<i class="fa-solid fa-align-justify me-1"></i>' + _("Notes")
-        #     ),
-        #     "amount": mark_safe('<i class="fa-solid fa-coins me-1"></i>' + _("Amount")),
-        #     "description": mark_safe(
-        #         '<i class="fa-solid fa-quote-left me-1"></i>' + _("Name")
-        #     ),
-        # }
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
diff --git a/app/apps/transactions/models.py b/app/apps/transactions/models.py
index c8eac96..8dd0782 100644
--- a/app/apps/transactions/models.py
+++ b/app/apps/transactions/models.py
@@ -103,7 +103,12 @@ class Transaction(models.Model):
         self.amount = truncate_decimal(
             value=self.amount, decimal_places=self.account.currency.decimal_places
         )
-        self.reference_date = self.reference_date.replace(day=1)
+
+        if self.reference_date:
+            self.reference_date = self.reference_date.replace(day=1)
+        elif not self.reference_date and self.date:
+            self.reference_date = self.date.replace(day=1)
+
         self.full_clean()
         super().save(*args, **kwargs)