What is Django DRF serializers in depth?

DRF serializers handle converting between complex data types and Python primitives (for JSON/XML rendering). Serializer types: Serializer (manual field declaration), ModelSerializer (auto from model), HyperlinkedModelSerializer (uses URLs instead of PKs). Validation: class UserSerializer(serializers.ModelSerializer): password = serializers.CharField(write_only=True, min_length=8) confirm_password = serializers.CharField(write_only=True) class Meta: model = User fields = ["id", "email", "username", "password", "confirm_password"] def validate_email(self, value): if User.objects.filter(email=value).exists(): raise serializers.ValidationError("Email already in use") return value.lower() def validate(self, data): if data["password"] != data.pop("confirm_password"): raise serializers.ValidationError("Passwords don't match") return data def create(self, validated_data): return User.objects.create_user(**validated_data). Nested serializers: class ArticleSerializer(serializers.ModelSerializer): author = UserSerializer(read_only=True) tags = TagSerializer(many=True, read_only=True). SerializerMethodField: word_count = serializers.SerializerMethodField() def get_word_count(self, obj): return len(obj.content.split()). Source: author_name = serializers.CharField(source="author.get_full_name"). Depth: class Meta: depth = 1 — auto-serialize nested relations. Custom write behavior: override create() and update() for complex saving logic. to_representation: override to customize serialized output per instance.