{"id":2003,"date":"2022-06-28T12:00:00","date_gmt":"2022-06-28T10:00:00","guid":{"rendered":"https:\/\/kindsonthegenius.com\/blog\/how-to-create-an-api-in-python-with-flask-step-by-step\/"},"modified":"2026-07-05T03:26:40","modified_gmt":"2026-07-05T01:26:40","slug":"how-to-create-an-api-in-python-with-flask-step-by-step","status":"publish","type":"post","link":"https:\/\/kindsonthegenius.com\/blog\/how-to-create-an-api-in-python-with-flask-step-by-step\/","title":{"rendered":"How to Create an API in Python with Flask \u2013 Step by Step"},"content":{"rendered":"

In this tutorial, you will learn how to create an SDK from the scratch. We would build an API using Flask. This API would retrieve student data from a SQLite database and allow performing other operations such as PUT, POST and DELETE. Next, we would create an SDK that would perform the same operations.<\/p>\n

At the end of this tutorial, you will understand the different between an SDK and an API.<\/p>\n

    \n
  1. Create the Student Class<\/a><\/li>\n
  2. Setup Your SQLite Database Connection<\/a><\/li>\n
  3. Make a Get Request<\/a><\/li>\n
  4. Get Record By ID<\/a><\/li>\n
  5. POST Request<\/a><\/li>\n
  6. Update Request<\/a><\/li>\n
  7. DELETE Request<\/a><\/li>\n<\/ol>\n

     <\/p>\n

    \u00a0Start a Server<\/strong><\/p>\n

    This is the main function, that starts the server<\/p>\n

    if<\/span> __name__ ==<\/span> '__main__'<\/span>:\r\n    app.<\/span>run(port=<\/span>8888<\/span>)\r\n<\/pre>\n
    Note<\/strong>: This has to be at the end of the file below all other functions in this file.<\/p>\n
    1. Create the Student Class<\/strong><\/h4>\n
    We would create a class the represents student details. This would be used to create Student object which we would store in our database.<\/p>\n
    The Student class is given below. Here we are using generating a UUID for each new student object create.<\/p>\n
    import<\/span> uuid<\/span>\r\n\r\nclass<\/span> Student<\/span>:\r\n\r\n    def<\/span> __init__<\/span>(self<\/span>, firstname, lastname, department):\r\n        self<\/span>.<\/span>id =<\/span> uuid.<\/span>uuid4().<\/span>hex\r\n        self<\/span>.<\/span>firstname =<\/span> firstname\r\n        self<\/span>.<\/span>lastname =<\/span> lastname\r\n        self<\/span>.<\/span>department =<\/span> department\r\n\r\n    def<\/span> __str__<\/span>(self<\/span>):\r\n        return<\/span> f'id:{self.id} '<\/span> \\\r\n               f'firstname: {self.firstname}; '<\/span> \\\r\n               f'Lastname: {self.lastname}; '<\/span> \\\r\n               f'Department: {self.department}'<\/span>\r\n<\/pre>\n
     <\/p>\n
    2. Setup Your SQLite Database Connection<\/strong><\/h4>\n
    You need to simply import the sqlite3 and Flask module. You may also need to install Flask using pip<\/p>\n
    import<\/span> sqlite3<\/span>\r\nfrom<\/span> flask<\/span> import<\/span> *<\/span>\r\nimport<\/span> json<\/span>\r\nfrom<\/span> student<\/span> import<\/span> Student\r\n\r\napp =<\/span> Flask(__name__)\r\n\r\ndef<\/span> go_home<\/span>():\r\n    c =<\/span> sqlite3.<\/span>connect(\"student.db\"<\/span>).<\/span>cursor()\r\n    c.<\/span>execute(\"CREATE TABLE IF NOT EXISTS STUDENTS(\"<\/span>\r\n              \"id TEXT, firstname TEXT, lastname TEXT, department TEXT)\"<\/span>\r\n              )\r\n    c.<\/span>connection.<\/span>close()\r\n<\/pre>\n
     <\/p>\n
    The function below returns a string for the ‘\/’ route<\/p>\n
    @app<\/span>.<\/span>route('\/'<\/span>, methods=<\/span>['GET'<\/span>])\r\ndef<\/span> go_home<\/span>():\r\n    go_home()\r\n    return<\/span> 'Welcome to the Students API!'<\/span>\r\n<\/pre>\n
     <\/p>\n
    3. Make a Get Request<\/strong><\/h4>\n
    We write a function to return a list of all records in the Students table.<\/p>\n
    @app<\/span>.<\/span>route('\/getStudents'<\/span>, methods=<\/span>['GET'<\/span>])\r\ndef<\/span> get_students<\/span>():\r\n    c =<\/span> sqlite3.<\/span>connect(\"student.db\"<\/span>).<\/span>cursor()\r\n    c.<\/span>execute(\"SELECT * FROM STUDENTS\"<\/span>)\r\n    data =<\/span> c.<\/span>fetchall()\r\n    return<\/span> jsonify(data)\r\n<\/pre>\n
     <\/p>\n
    4. Get Record By ID<\/strong><\/h4>\n
    The code below takes an student_id and returns the student’s record<\/p>\n
    @app<\/span>.<\/span>route('\/getStudentById\/<student_id>'<\/span>, methods=<\/span>['GET'<\/span>])\r\ndef<\/span> get_student_by_id<\/span>(student_id):\r\n    c =<\/span> sqlite3.<\/span>connect(\"student.db\"<\/span>).<\/span>cursor()\r\n    c.<\/span>execute(\"SELECT * FROM STUDENTS WHERE id=?\"<\/span>, (student_id,))\r\n    data =<\/span> c.<\/span>fetchone()\r\n    return<\/span> json.<\/span>dumps(data)\r\n<\/pre>\n
     <\/p>\n
    5. POST Request<\/strong><\/h4>\n
    To add a new student record to the database<\/p>\n
    @app<\/span>.<\/span>route('\/addStudent'<\/span>, methods=<\/span>['POST'<\/span>, 'GET'<\/span>])\r\ndef<\/span> add_student<\/span>():\r\n    db =<\/span> sqlite3.<\/span>connect(\"student.db\"<\/span>)\r\n    c =<\/span> db.<\/span>cursor()\r\n    student =<\/span> Student(request.<\/span>form[\"firstname\"<\/span>],\r\n                      request.<\/span>form[\"lastname\"<\/span>],\r\n                      request.<\/span>form[\"department\"<\/span>]\r\n                      )\r\n    print<\/span>(student)\r\n    c.<\/span>execute(\"INSERT INTO STUDENTS VALUES(?,?,?,?)\"<\/span>,\r\n              (student.<\/span>id, student.<\/span>firstname, student.<\/span>lastname, student.<\/span>department))\r\n    db.<\/span>commit()\r\n    data =<\/span> c.<\/span>lastrowid\r\n    return<\/span> json.<\/span>dumps(data)\r\n<\/pre>\n
     <\/p>\n
    6. Update Request<\/strong><\/h4>\n
    To update a student record we pass the student_id in a url and pass the student object in the request body. The request must be sent as x-www-form-urlencoded<\/em><\/strong>.<\/p>\n
    @app<\/span>.<\/span>route('\/updateStudent\/<student_id>'<\/span>, methods=<\/span>['PUT'<\/span>])\r\ndef<\/span> update_student<\/span>(student_id):\r\n    db =<\/span> sqlite3.<\/span>connect(\"student.db\"<\/span>)\r\n    c =<\/span> db.<\/span>cursor()\r\n    student =<\/span> Student(request.<\/span>form[\"firstname\"<\/span>],\r\n                      request.<\/span>form[\"lastname\"<\/span>],\r\n                      request.<\/span>form[\"department\"<\/span>]\r\n                      )\r\n    print<\/span>(student)\r\n    c.<\/span>execute(\"UPDATE STUDENTS SET firstname = ?, lastname =?, department =? WHERE id=?\"<\/span>,\r\n              (student.<\/span>firstname, student.<\/span>lastname, student.<\/span>department, student_id))\r\n    db.<\/span>commit()\r\n    return<\/span> json.<\/span>dumps(\"Record was successfully updated\"<\/span>)\r\n<\/pre>\n
     <\/p>\n
    7. DELETE Request<\/strong><\/h4>\n
    The function below deletes\u00a0 a student record base on the Id in the url.<\/p>\n
    @app<\/span>.<\/span>route('\/deleteStudent\/<student_id>'<\/span>, methods=<\/span>['DELETE'<\/span>])\r\ndef<\/span> delete_student<\/span>(student_id):\r\n    db =<\/span> sqlite3.<\/span>connect(\"student.db\"<\/span>)\r\n    c =<\/span> db.<\/span>cursor()\r\n    c.<\/span>execute(\"DELETE FROM STUDENTS WHERE id=?\"<\/span>, (student_id,))\r\n    db.<\/span>commit()\r\n    return<\/span> json.<\/span>dumps(\"Record was successfully deleted\"<\/span>)\r\n<\/pre>\n
     <\/p>\n
    I hope you followed and did the procedure successfully. For more, please subscribe to my YouTube Channel.<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
    In this tutorial, you will learn how to create an SDK from the scratch. We would build an API using Flask. This API would retrieve … <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"pagelayer_contact_templates":[],"_pagelayer_content":"","footnotes":""},"categories":[7],"tags":[],"class_list":["post-2003","post","type-post","status-publish","format-standard","hentry","category-python-tutorials"],"_links":{"self":[{"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/posts\/2003","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/comments?post=2003"}],"version-history":[{"count":1,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/posts\/2003\/revisions"}],"predecessor-version":[{"id":2171,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/posts\/2003\/revisions\/2171"}],"wp:attachment":[{"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/media?parent=2003"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/categories?post=2003"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kindsonthegenius.com\/blog\/wp-json\/wp\/v2\/tags?post=2003"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}