[Django]-"Not a valid string." – error when trying save dict to TextField in Django Rest Framework

Try this in your serializer:

class ApiLogSerializer(serializers.ModelSerializer):
    incoming_data = serializers.JSONField() # change is here

    class Meta:
        model = ApiLog
        fields = ('incoming_data',)

This will convert your JSON dict to string and store in DB as Text.

Refer to the official DRF documentation for more details