Python Tornado Interview Questions And Answers

Python Tornado Interview Questions And Answers

Python Tornado is a flexible and scalable web server and web application framework. Its main attraction is the capability to handle several thousand simultaneous logged-in users. Several companies require a candidate who is well versed in Python Tornado. If you are also looking for a career in Python Tornado, you must clear an interview successfully. Continue reading to know about the top Python Tornado interview questions and answers.

Python Tornado

Python Tornado, developed by FriendFeed and later acquired by Facebook, supports various modules and protocols to make a quality user experience. Before Tornado, web servers had an issue with handling several connections simultaneously, code-named C10K Problem. Tornado was a solution to the C10K problem. Tornado allowed websites to have several requests per second. Read the top Python Tornado interview questions and answers to gain more knowledge on the topic.

Top 20 Python Tornado Interview Questions And Answers

1. What is Python?

A. Python is a high-level programming language used across various industries and applications. It is interpretative and object-oriented with dynamic semantics. Python also has high-level data structures included with dynamic typing and binding. These features make it suitable for faster application development and combine various other technologies.

2. Who is Python’s creator?

A. Dutch programmer Guido van Rossum created Python.

3. When was Python Released?

A. 20th February 1991 was the date of the initial release of Python.

4. What are the major features of Python?

A. Some major features of Python are:

  • An elegant syntax that makes easy-to-read programs.
  • An easy-to-use language that makes programming simple. Such language makes Python an apt choice for educational purposes, prototype development, and intermediate programming tasks.
  • A large standard library that supports various programming tasks like web server connections, text searching with regular expressions, and reading and modifying files.
  • An interactive mode that makes testing snippet codes easy. IDLE, which is the bundled development environment, helps in this task.
  • An easy extension by adding new modules that are implementable through compiled languages like C or C++.
  • A possibility to embed it into an existing application to create a programmable interface.
  • A wide range of supporting operating systems such as macOS, Microsoft Windows, Linux, Unix, Android, and iOS.

5. Describe some useful programming-language features of Python?

A. Some useful programming-language features of Python are:

  • Availability of raw numbers like a floating-point number, complex number, and unlimited-length long integers. Various ASCII and Unicode strings. Plenty of lists and dictionaries.
  • Support for classified multiple inheritance object-oriented programming.
  • Grouped codes according to packages and modules.
  • An exceptional error handling through raising and catching exceptions of language.
  • Dynamically typed data allows combining incompatible types. It allows rapid error fetching through exception raising.
  • Generators and comprehensions.
  • Automatic memory management allows manual allocation and reduction of memory in code.

6. What is Python’s application?

A. Python is a high-level programming language used for testing microchips and building applications and video games. It is also used in AI, machine learning, and data management. Through third-party libraries, the building of any applications is possible using Python.

7. Explain PyPI (Python Package Manager).

A. Python Package Manager is a Python utility to simplify tasks to locate, install, upgrade and remove Python packages. It determines whether the latest version of a software package is available in the system or not. Then it installs or upgrades to the available package from a local or remote host.

8. How will you use the Python web application framework?

A. Web application framework is usable in building web-enabled applications. It is possible to create anything in between simple blogs and complex AJAX applications.

9. Name a few familiar Python web application frameworks?

A. Some extensively used Python web application frameworks are:

  • Django – A high-level Python web application framework.
  • Web2py – An open-source full-stack python web application framework. Suitable for scalable, secure, and portable applications.
  • Flask – A lightweight Python web application framework.
  • Grok – An open-source Python Web Application Framework.
  • Tornado – A scalable, non-blocking web server in Python web application framework.
  • cherrypy – An object-oriented Python web application framework.
  • Turbogears – An AJAX-integrated Python web application framework.
  • Google app engine – A platform to develop and host web application frameworks (including Python) in data centers managed by Google.
  • Pylons – A lightweight Python web framework for fast and flexible development.

10. What is Python Tornado?

A. This is one of the most basic among top Python Tornado interview questions and answers. Python Tornado, developed by FriendFeed, is a Web Application Framework that gives an asynchronous networking library. Tornado is useful in applications that need open-ended connections with multi-side interactions. It is not based on WSGI like other Python Web Application Frameworks.

Python Tornado runs one thread per process. It is suitable for long-duration connections used for applications for long polling. Long-duration connection is possible through scaling thousands of open connections with non-blocking input and output.

11. Explain Python Tornado’s USP.

A. Tornado is fast, light, and simple. Also, Tornado gives full control over the application that is under development. Such excellent control isn’t available in other Python Web Application Frameworks.

12. Explain the Components of Python Tornado.

A. Python Tornado has four major components. They are:

  • Web Application Framework: It has a Request Handler that is further classified for creating web applications. Several other supporting classes are also present.
  • Client and Server: HTTP implementation has HTTPClient and AsyncHTTPClient to communicate with Client and Server, respectively.
  • Networking Library: The library has the basic framework for HTTP components. Some examples are IOStream and IOLoopserving. Several other protocol implementations are also possible through the Networking Library.
  • Coroutine Library (Tornado.gen): It is similar to the inbuilt coroutine tool initially released in Python 3.5. With the help of a coroutine library, writing asynchronous codes in a more upfront manner is possible. The previously used method was through chaining callbacks. When the need for smoother implementations rises, preference is for Native coroutines compared to Tornado.gen module.

13. How do Tornado and HHTP servers function together?

A. The combination of Tornado and HTTP acts as a full-stack replacement of WSGI. There are several limitations in using this combination, but it gives the developer full control in development.

14. How is a professional benefit from using Tornado?

A. Some of the known benefits to using Python Tornado are:

  • The small and easy framework of Tornado allows a professional to read and understand the source code.
  • Due to the compact nature of the source code, it has similarities with the nature of Python. Developers find creating libraries easier in comparison to Django because of the compact nature.
  • Tornado is an apt framework to create HTTP plus JSON services because of the easy combination. Python Tornado is compatible with Python 3 or PyPy, and there is a 2.5x performance boost using Tornado with PyPy.
  • Tornado doesn’t have ORM-related information. Its framework supports an Event-based paradigm through IOLoop. So Python Tornado becomes useful for all network-related programming. Python Tornado is also applicable to expire cache.
  • Because of features like Tornado.ioloop.PeriodicCallback, Tornado allows testing cron logic. The test for Cron logic in Tornado is through development mode. Production mode asks permission from System Administrator.
  • Python Tornado can deliver better templates because of its use of the templating system.
  • Most of the writing of HTTPServer is in Python. But even then, it provides efficient means to cater to more than 2000 requests in a minute without any hassle.

15. How does Tornado adversely affect programming?

A. Some notorious, adverse effects of using Python Tornado in programming are:

  • Tornado has a non-blocking paradigm while writing IOLoop. A developer might not always remember to keep the IOLoop unblocked while writing code. This is the issue with most of the libraries in Python because all of them are blocking. To mitigate this error, a developer can try running multiple Tornado processes as proxies behind Nginx. It is because Nginx can eliminate the risk of blocking through the tornado framework.
  • A developer cannot rely entirely on WSGI mode because it doesn’t allow them to use all the features of Tornado.
  • Memory storage of Tornado is as a full file and not as a temporary file.
  • It can sometimes be hard to find code examples for Python Tornado. It is because the community is yet developing and have only a limited number of developers.

This question is important in top Python Tornado Interview Questions and Answers. It is because even if a web framework is useful, it can have disadvantages. And knowing those disadvantages is integral to clearing an interview.

16. Explain Blocking and Asynchronous terms used in Tornado.

A. Tornado has single-thread event loops. Such event loops reduce the concurrent connection expenses. Because of such loops, all codes try to be non-blocking and asynchronous to allow one process at a time. Both these terms may appear the same but have different meanings and functions.

  • Blocking

Blocking of a function occurs when it waits for some operation to be complete so it can start. There are several reasons for blocking, such as input/output or mutexes. While utilizing the CPU, every function tends to block for a short amount of time. In Tornado, a developer will only face the issue of network input-output. But because the other fields might be useful in the future, the developer needs to reduce all means of blocking errors.

  • Asynchronous

Asynchronous functions return output even before completing the function. So, while getting an output, some actions must have already started in the background. A developer generally uses the asynchronous function in Tornado because of its ability to return placeholder objects. But this isn’t applicable for IOLoop because it uses callbacks o complete functions.

17. What are the major differences between Tornado and Django?

A. Tornado and Django are frameworks of Python, but both of them have different functions and features. And their differences are a major topic in top Python Tornado Interview Questions and Answers. The major differences of Python Tornado and Python Django web application frameworks are:

Tornado supports scalability to a large number of open connections. Because of the scalability, Tornado becomes an apt choice for long polling applications. It is because long polling applications need a long-lasting connection to several users at a time.Django is a high-level web programming framework in Python. It allows faster development and deployment along with better design.
Tornado is comparatively more flexible. It also supports web sockets, TCP, and several additional communication protocols.Django provides support to various features like ORM, routing, background management, etc.
Tornado has non-blocking and asynchronous features.Django only has an asynchronous function. These are achievable through celery, asyncio, aiohttp, etc.
Major companies like Facebook, Delivery Hero, HENNGE KK, Zalando, Avito, TravelPerk, Uploadcare, Digital Services, Peak-AI use the Tornado framework.Some Django websites are Instagram, Disqus, Knight Foundation, MacArthur Foundation, Mozilla, National Geographic, Pinterest, and Open Knowledge Foundation.

18. What are some specialties of Tornado Templates.

A. The templates in Python Tornado are flexible and scalable. The templates are HTML tags with the embedding of Python expressions and sequences through markup language. These features of Tornado templates are visible and helpful while developing software. The template inheritance is also an extremely helpful feature of Tornado.

19. Explain the use of UI Modules in Tornado.

A. UI Modules help Tornado execution easier. They also help add basic UI widgets to the website. UI Modules act like functions that render page sections. They also have their CSS and JavaScript interfaces.

20. Explain Cookie Security in Tornado.

A. The cookies in Tornado are not safe because they are alterable by end-users. To ID the current users, a developer needs to sign cookies. By doing so, the user doesn’t have a chance to tamper with the cookies. Tornado has the means to sign cookies through get_secure_cookie and set_secure_cookie. But to apply these methods, the developer must specify cookie_secret while writing the code.

The cookie only provides the security for connection. There is no discretion in the cookie itself because anyone can see the details of the cookie. The cookie also expires after 30 days. Tornado has a multiple signing keys feature that can periodically rotate the signing key.


Many multiuser websites currently prefer Python Tornado. It is because of the ability to provide many users simultaneous access to their website. Other than that, it is flexible and compact, making codes more comprehensible. We discussed all the important Python Tornado interview questions and answers in this article. You can refer to those for helpful knowledge to clear interviews successfully.