TypeError: Object of type is not JSON serializable
In order to use jsonify() you have to make serializable the class you need to jsonify. Add to that class a function similar to the following:
class Version(db.Model): __tablename__ = 'versions' id = db.Column(db.String(), primary_key=True) file = db.Column(db.String(80), nullable=True) application_id = db.Column(db.Integer, db.ForeignKey('applications.id')) def serialize(self): return {"id": self.id, "file": self.file, "application_id": self.application_id}And then jsonify de serializaed version of the object, and not the objetc itself:
jsonify(result.serialize())
You probably want to use ModelSchema instead of Schema.
class ApplicationDetailSchema(ma.ModelSchema): class Meta: model = Application fields = ('id', 'name', 'versions')ModelSchema dumps the related foreign key objects as a list of id(s) by default which is JSON serializable.
Try with json.dumps() and json.loads()