Python Flask Tutorial: Full-Featured Web App Part 1 - Getting Started

In this Python Flask Tutorial, we will be learning how to get started using the Flask framework. We will install the necessary packages and get a basic Hello World Application running in our browser. Let's get started...
The code for this series can be found at:
github.com/Cor...
Django Tutorials to create this same application:
• Django Tutorials
Python Installation:
• Python Tutorial for Be...
Virtual Environment Setup:
• Python Tutorial: virtu...
• Python Tutorial: How I...
Sublime Text Setup:
• Setting up a Python De...
If name equals main explanation:
• Python Tutorial: if __...
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#Python #Flask

[@roohas6311]

taught me more in 17 mins than my lecturers did in a year, thank you!

[@transcendentfish5824]

guess you were not paying attention then lol

[@felicytatomaszewska]

@@transcendentfish5824 Exactly, or more realistically he never enrolled in a college degree. Corey is great teacher but it does not mean one should discredit the class teachers. Class curriculum is deep and lengthy which focuses more on fundamentals.

[@plekkchand]

@@felicytatomaszewska Nonsense. There is some slight exaggeration in the OP's claims, perhaps, but exactly which "class teachers" (to reproduce your solecism) are you talking about ? Are you by chance acquainted with the OP's teachers? Your remarks make normal leaping to conclusions look like logical precision.

[@felixs4523]

probably because you were listening this time

[@gracebriody9053]

As a computer science teacher, I can say that there are plenty of shit computer science teachers. So if he says he didn't learn anything, he probably didn't.

[@salmansiddiqui9502]

Thank you for creating this series, Mr. Corey. I finished it and found it insightful, engaging, and an excellent introduction for anyone looking to invest in Flask. For those watching in 2025 and hesitant about starting an older course-go for it! The code has changed very little over the years, and the comment section is always available for support.

[@easontee1351]

Watching tutorial videos are better than reading a wall of texts. Very good explanation and demonstration!

[@frankfunk9188]

I read about this in 'Flask web development'. Spent probably a good hour on it and didn't understand things half as good as via your video in 17 mins. Thank you!

[@omuinetimi]

got a backend dev job yet?

[@kanefoaker]

i agree with this comments. .. this is good "tutorial" methods video

[@myblrapp9627]

If you are really interested, complete Harvard CS50 course. Then come back here.

[@shazam2112]

00:00 - Intro 00:20 - Application Intro 2:58 - Installing dependencies 4:25 - Creating flask app 7:17 - Running the flask app 9:20 - Adding HTML 11:58 - Running without env variables 14:03 - Adding another route 15:00 - Handling multiple routes with one function

[@Web3Phoenix]

For those watching in 2023 for this video some commands have changed for running flask: to start a development server => `flask --app run` and not `flask run` and to enable debug mode it is: `flask --app run --debug` and not `set or export(for mac or unix user) FLASK_DEBUG=1` I suggest you open up the documentation along while watching the tutorial

[@hellfire8535]

Thank you!

[@nikosmichos124]

thanks!!!

[@yasouko8625]

Thanks

[@sarankumar13]

Bro for people in 2024 help pls

[@Your_mom_calls_me_luka]

@@sarankumar13 are you fucking serious mate? -____-

[@gameexplorer9213]

I cracked the interview as fresher in Django. I have self-taught my self. Most of the credit goes to you @corey schafer. Now, back to here, to learn flask.

[@jamaalbuckley5266]

I can't thank you enough for these tutorials. You have made learning Flask (and other Python modules) MUCH easier, explained in terms that the person who is learning to code on their own (like me) can easily understand. Thanks again.

[@novicetech1]

Hey Corey - Another truly awesome tutorial series. This seems way easier than django. When I first started with Python I never dreamed I would get this far. Thanks to you I've exceeded my own expectations. Just joined your patreon too. It's not much, but it's my way of saying thank you for all you give to us wanna be geeks :-)

[@coreyms]

Thank you! That helps more than you know. I really appreciate that and I'm glad you've found the videos helpful!

[@stackcanary3368]

Hey Corey after seeing your video about future plans and when I saw Flask popping into screen I immediatly clicked the link and liked the video. You're doing a great job, your instructions are clear, structured and most of all helpful! Beside learning Python by books, your videos are an awesome perspective!

[@aliyueaudu1077]

@@coreyms sir you videos has been awesome in ep5 i encounter issues dropping my user and post table, am getting database is locked error, please help

[@sarthakvashisth9817]

You are a very good teacher Corey. The way you explain concepts is extraordinary. I started watching your video tutorials since 3-4 months and I will recommend every programmer who wants to learn python to watch your videos. Keep up the good work man.

[@randylloberalara9795]

Hey Corey, I'm a CS student that happened to learn C# as my first language and been leaving in Visual Studio for a couple of years now. I decided I wanted to learn Python and was so lucky because I came across your channel. Just wanted to say thank you for the amazing content you putting out there and for all the help. Joined the channel right away, although monetarily it's not much, its my way to appreciate your effort.

[@scanlan8700]

I have flailed at Flask for a while now. This approach works. I bit the bullet and am doing everything I see in the tutorial. The concepts are ringing loud and clear. Thank you, Corey. During this virus crisis you are helping restore my sanity.

[@miosz952]

Thank you so much for this series. After learning the basics of python I didn't know what to learn next. I saw a few ideas like data science, web-development, machine learning etc. I decided to learn about them to decide what intrest me the most. I wanted to start with flask, but I couldn't find any resources for learning that will well explain this stuff. I just finished this first episode, and it's the best one that I found, I'm definetly going to learn more from this series.

[@hritabanroy6911]

I tried read the documentation, stumbled through several KZbin videos till I found this gold. Simple and amazing! Love how you didn't bombard information at our face and it was actually understandable even for someone learning web frameworks for the first time.

[@michaelcook2233]

I concur with others about your teaching style. You speak fairly quickly, but because of your straight-forward approach and gift for clear and logical explanation, the quickness of your speaking doesn't matter, it only means you get through more material in less time. I am learning on Treehouse, from a supposedly world-class Python developer. Yet time and again I return to your videos for clarification, because as good of a developer as the Treehouse Python instructor is, he leaves me saying to myself ".....WHAT?" pretty much every single time. And then I watch your video on the topic I am learning, and it all makes sense. Thank you. When I land a developer job, I will most certainly become a contributor to your Patreon.

[@coreyms]

Thanks!

[@Marcus001]

I concur

[@TomLeg]

I like the talking fast ... some other educational videos I speed up to 125%, even 150%. But maybe you should have a note telling people that find it too fast, eg people with English not as their first language, they can slow it down, too.

[@isaacbawangisah6096]

Great work done! I think this tutorial was uploaded 5 years ago but it is still more relevant than ever. Thank you very much.

[@pointerish]

Hi Corey, I just became a patron for you. I really appreciate your efforts, please keep being the great teacher you are.

[@ryann7741]

@Langston Raiden i saw similar comments somewhere else ..sus

[@Anahdhhsxjfh]

@@ryann7741 Sussy amogus balls imposter sus

[@manthanadmane]

Simply incredible. Same application in Django and also in Flask. An application that covers databases and other ins and outs of working with a framework. Simply genius. Thank you for all your efforts.

[@richardpilhofer3994]

This the proper way to do a tutorial. Show people how to make something useful. Thank you sir.

[@gavincraddock5772]

These tutorials are amazing. I'm an experienced (20+years) programmer and these videos show exactly what I need to move into new areas such as Flask - so much clearer than other tutorials, with every step shown and every misconception covered. Very, very impressed - thanks.

[@ashishdeora8522]

Thank you, Corey, for this amazing masterpiece. The entire developer community is obliged to you :)

[@amit-mishra]

How do you have his photo after your name?

[@ashishdeora8522]

@@amit-mishra I am a patron. Have joined his community

[@lucywang8643]

This series is great in introducing me to the whole full stack of web development. However, I wish more details was included when existing modules were used from outside. I thought I understood everything until I researched on other things and then I finally knew what you were actually doing.

[@stkgok]

I am from writing turkey, I dont speak english but I understand this videos. Today teacher's day, thank you my teacher corey :)

[@arda17141]

Sıtkı Gök I’m also Turkish

[@samatmarat9853]

@@arda17141 seviyorum sizleri ))

[@SS-xt5ul]

merheba from Istanbul

[@mikesmusicmeddlings1366]

Man you are such a good teacher, I did physics in college and wish I had teacher like you. I would know so much more by now

[@pearlearring]

Thank you so much for these tutorials Corey. I greatly appreciate your work. I don’t know what would have I done without these tutorial😭. The best programming channel on KZbin.👌🏻

[@NotIkram]

I usually do not comment on youtube videos but I had to comment on this. You made everything i've been trying to learn the past few weeks so much easier. Excellent teacher!

[@codingspace]

one thing is sure, your tutorial may be a little bit hard to follow for a beginner, but the best thing is you teach with all the best practices, love it. keep up the good work

[@johnreefervermont4874]

Corey, when your site is complete, I am going to take every course you offer. You are awesome and I own you a lot more than you can imagine. Great work....

[@thedailyscoop254]

Thanks alot Corey. To be honest you are the best teacher I have ever met and I'm confident after this course am going to finds a job. Thanks again.

[@coreyms]

Thanks. Best of luck!

[@nacholupotti3644]

How is possible that you have the best tutorials for all the topics in python? You are crazy man! Thank you for all

[@DistortedV12]

You are the man Corey!! Thank you for all you do, was hoping on this given your javascript background.

[@coreyms]

I don't do much javascript in this series, but I'll be sure to cover that in a future video if it's something you're interested in!

[@deadbod4]

I am a newb and I usually use multiple sources to cover one topic, this is by far one of the best Tutorials covering the Flask topic. I always had problems with using command prompt because simply I'm not a pro at it but with your video I'm able to follow through. Thank you so much for your contribution!

[@danielsjodin2497]

Just love all your videos Corey! And this last series is if possible better then the others. The audio quality, the pace, details and that you build something from ground up using applicable tools like Bootstrap is a few things I appreciate. Keep em coming :)

[@gubliod]

Why did this teach me more than a whole programming unit at university... Thanks for this! :-)

[@kawaljeetsingh865]

Hello Corey, I have watched all your videos on Python. The way you teach is just simply awesome. I have gained so much knowledge from your tutorials. I am currently learning flast from the tutorials and I want you to please upload a series for Django or Data science (The one you feel you are good at). Thanks For The Knowledge You Share With Us.

[@ragavsathis]

Crisp and neat video about Flask over-view. Corey Schafer as usual rocks

[@KernelKudos]

I left the 16 hour BORING FLASK COURSE FOR A SIMPLE APPLICATION and NOW im watching your videos , you explain things fast and clearly , THANKS BECAUSE OF YOUR GREAT VIDEOS :))💙💙

[@ifredpingplay468]

The series i was searching from past 6days and each time i was got mess information even sometimes broken information..But now " accurate knowledge= information + perfect explanation " thanks man :) for uploading this series

[@babukothandaraman984]

Hi Corey, First of all, let me congratulate you for the way you've structured your tutorial videos. Thought I've watched only till the "Forms" video, I can say that your tutorial is 'top shelf' stuff, just like those Schafer Chardonnays. Yup! Oaky, full bodied Schafer Chardonnay is one of favourites. And your videos are power-packed, non-stop encyclopedia of respective coding. What I like about your videos are: 1. Your teaching methodology is clear and crisp and at the same time, just to the point. For example, in Part 1, you've clearly gone through the evolution of how to run the program on python; from setting the environment variables on command prompt to how to avoid procedure. 2. Audio and vidoe qualities are fantastic. 3. Particulary, I would like to underline that you've avoided any extra graphics, music et al. And actually, your voice sounds like music to the ears. Yup! When you decode the the coding, line by line and block by block, we can easily understand the logic behind the coding. Overall, a great effort and an great result! Thanks BK

[@amirhosseinahmadi3706]

You're a really powerful explainer, dude! Hope to see more and more videos from you! As a side note, I'm watching this series after I watched the Django series and I personally like Flask much more than Django.

[@kilbeam99]

I started the Django series and got to the users section when I realized there was no good Django documentation for what I needed to implement (google Calendar API). There is very thorough Flash documentation though, so I am excited to see what Flask is like now!

[@giv123]

i've built a few websites with django now based on corey's original django video (which was great). Now it's time to get into flask to become a more well rounded python web developer. From the offset this reminds me a bit more of how node.js lays out urls and pages

[@quentincaldway]

These videos are amazing I starting learning Django 3 days ago and it seems as if Flask is so much easier! I love them both! Your tutorials are phenomenal! Preciate you for time and effort bro!

[@biswajitsahoo1456]

can you provide me the link of django tutorial which might be a good tutorial according to you... either in youtube or udemy... it shall be greatly appreciated....

[@raymondmichael4987]

I've just saw this channel today; already subscribed as soon as you said Django ; um looking forward to it, great explanations sir

[@PATRICKCHUAD]

I think I found a great tutorial on flask, I'm excited to go through this series. Thanks Corey for sharing your knowledge to the dev. community.

[@amekoudjikouessi]

Hi Corey! I just want to thank you for this great tutorial. you really make python flask learning easy as having fun.

[@PrivilegeHDGaming]

I dont usually comment on videos but you deserve it mate. WELL DONE you are better than anyone else.

[@PyMoondra]

Nice flask tutorials, it's on my backlog to learn. Django is something I also have never touched. So much to watch!

[@codelearnry9034]

I get so inspired each time I listen to Corey. He has truly inspired me to start my own youtube channel. Corey thanks a lot for your good works.

[@coreyms]

Thanks! And best of luck with your channel!

[@soumitripattnaik]

Here comes the best Flask tutorial of them all.

[@pranjalnama2420]

i came to know about this channel from krish naik youtube video. it was most needed.

[@Alphabetbubi]

Thank you so much for the detailed introduction! Going through every step of the way was exactly what I needed to get Kickstarted with this topic!

[@faiquejatu8649]

How does it worked for you? ur review

[@derrickodhiambo7767]

This is the best series I've seen in a long while. Thanks Corey for simplifying flask. Once I get the means I'm definitely supporting this awesome channel.

[@dungaland]

Hi, Derrick

[@derrickodhiambo7767]

@@dungaland Ssup man

[@arminpourbeik]

The best Flask tutorial on the web! Thanks a lot!

[@espressoshot21]

Thank you so much for making this tutorial series. I checked out another one before this and it was confusing as hell but you touch bases on every components, and it really helps.

[@kal5211]

Wow, this is more helpful than the CS50 explanations. Thank you!

[@gabriellemoran6965]

Great teaching, thank you. You have the knack of knowing to explain all the little things we have to write to make things work right but never understood why!

[@fiddlepants5947]

I'm about 9 mins into the video and loving it... I don't usually love things on KZbin

[@tarikca427]

Oh man! You know, your videos is more addictive than drugs, I check everyday for new ones

[@ThinkinThoed]

Click on the "bell" icon next to the subscribe icon, you'll get an alert on your phone every time he uploads. :)

[@spencercraig8911]

Sounds like you need a new dealer!

[@colinmoriarty9640]

Every time I feel too dumb to learn or have nearly given up hope, you come to the rescue. Thanks for this series :)

[@kaizersozy]

I love the way you explain things in detail, very helpful :) thanks men !

[@CorySchneiderOfficial]

I ran through this tutorial series copying everything line by line and I'm on my second go now, but will follow along while building my own web app from a previously CLI only program I've been working on so my coworkers can use it, too. Thanks Corey for such an amazing KZbin channel!

[@user-tx1ip]

Hi Corey, I learnt this FLASK framework last month, and this month I did Django. Thanks a lot.I really like the way you teach. Could you do a video about RESTFUL API in the further please:)

[@shibajyotidas2043]

your speech is crystal clear and very understandable brother, i prefer this to be the best flask tutorial in you tube, great job, make one in Django also

[@zack3ry01iver6]

I was looking for drinking flasks and now I know how computers work thanks now I drink even more

[@invisaligner1435]

Great stuff. For PowerShell users the command is: > $env:FLASK_APP = "hello" > flask run

[@paddyd7642]

Thank you so much for this. I am going to donate on Patron first thing after I find job.

[@coreyms]

Thanks! That really helps a lot.

[@puravida77700]

Me too. Your tutorials are super helpful

[@MrKkfar]

@Corey You are probably 'the most fantastic teacher' I have come across all my life. You make complex subjects look so wonderfully simple that it's like "Now you don't get and now you do!". My full tributes to your way of teaching. God bless you!

[@cloudagnostic]

This looks like a great 👍🏾 flask tutorial. I am looking forward to watching this series. Thank You! Plus 1 sub!

[@mangaart3366]

Thank you so much for this! I was about to give up because I started reading the documentation first but your tutorials are amazing!

[@keshavnayak2812]

Excellent Corey huge fan of ur channel

[@AdamSmith-ux5if]

Hell yeah! You finally released the flask tutorial! I remember when you said you were going to this in December. Thanks for making this Corey! 🍻

[@thomasyusuf1366]

note to everyone, if youre having problems running your app and youre seeing an error, you need to set up a virtual environment on your windows powershell or command line.

[@ludwighurtado1719]

Thanks for the video nice. Following all your tutorials. I started taking online Harvard courses. I did appreciate the simplicity and form of instruction. Keep up the good work Corey and may you receive many blessings for your effort and time!

[@mustafayasin4469]

Finally! saving lives again! thank you so much!!

[@majesticchicken3213]

See the first minute of the video watching him reviewing what he's gonna do..nicee..im sub instantly..been searching for this kind of tutorial..thank you so very much kind sir

[@amitdigraj7443]

so, I am here after 4 years of release of video, do i need to check out on any other video as you know updates for frameworks are often these days. or go on with this video where there aren't much changes

[@Crucizer]

It's really awesome that you build the exact here as you build in the Django tutorials, so a person can easily compare both of these.

[@krishivdhupar1639]

Amazing Video, great teaching

[@twhizzay]

You're the best Corey! Concisely taught. What every teacher should strive to do in their educational videos.

[@greciawhite6413]

thank you! i couldnt get my flask app to run using git bash but it worked after adding if __name__ == "__main__": app.run(debug=True) at the bottom

[@vonderasche2963]

I made it thru the whole series. I learned a lot. Ive written several machine learning neural networks using tensorflow but I needed a way for others to use them. I was able to deploy them to a website using flask. I really appreciate the high quality videos you release. Also having the git repository to look at the code was great.

[@ivanatkalcec]

Thank you so much. You are a very good teacher :)

[@sep69]

Very nice tutorial ! I have been dabbling with flask for a few weeks now and I love it. Still learned some nice things in this first tutorial. Thank you very much creating them :)

[@vahidsediqi5638]

Anyone watching and learning this in 2020 during lockdown ?

[@omuinetimi]

lmao

[@shibilahamed9327]

yep

[@codeout8529]

Yes!

[@chinmaybhat9636]

Yes

[@carlosfernandez6470]

Me too

[@eonblue32]

This is AMAZING. As a new programmer I tried to dive into Flask and got really overwhelmed and down on myself. This video is EXACTLY how I needed it explained and a huge ray of hope for me! Thank you Corey!

[@lightninginmyhands4878]

You're a legend. Hope to see you at PyCon

[@prashanthxavier3407]

Glad to see free tutorials with brilliant quality in teaching.

[@shivaranjanmenon1543]

Hi Corey, thanks for this playlist! May I know if these videos are still relevant to the current version of Flask, as of August 2021? Or has the Flask framework completely changed since the time you posted this playlist?

[@SaurabhKumar-qc6og]

Hey Corey, I liked the way you touched each concepts while explaining the framework. Especially that decorator concept, virtual environment concept and many more.

[@bsoyuj]

Waiting for the django series

[@sparkyUK]

@@Ihavetoreturnsomevideotapes - remove yourself from anything online. You have zero useful input to humanity.

[@futureastronaut-3378]

well, i usually don't learn from videos because they take time and am not a fun of longer videos, and when i saw the length of the videos and that it's been posted 5 years ago i did hesitate. but eventually decided to give it a shot and am telling you, definitely you got a lifetime subscriber since am just starting my learning process into this FullSstack dev. may allah bless you :)

[@yahyacherif271]

السلام عليكم اخي هل هذه السلسلة تنفع اشتغل عليها الآن؟ هل واجهت صعوبات معها؟

[@futureastronaut-3378]

@@yahyacherif271 نعم يمكنك ان تشتغل عليها بعينيك مغمضتين...

[@ganeshkumar-ye4zq]

I did this in windows command prompt. The only problem I had while setting up was when setting environment variable to flaskapp.py. As explained above the command is: set FLASK_APP=flaskblog.py Notice: there is no space before and after equal operator(=).

[@alixaprodev]

thank you so much. i spend about 5 mints to figure it out.

[@kandys93ngojackson96]

Thanx for your videos!! I'm french and i understood everything u said! Now i do understand better how to start my teacher ain't as efficient as you!! Thanks a lot!

[@imenbou8665]

hello thank you for this amazing tutorial ..but when i run my programm i have an error : Failed to find Flask application or factory in module "flask". Use "FLASK_APP=flask:name to specify one......how can i correct this ..please

[@TestingRG3003]

add one more line in your program- app.run(debug=True)- this line will give you a IP address in your ide😊

[@jja262]

I built my first Flask app by following along. Thank you for the very clear tutorial!

[@14dagip]

Corey... you are a bad a$$. Love it!!

[@puhalenthirameshvidhya350]

Out of the ten videos that I watched, this was the only one that I understood. THANKS!!!

[@sarankumar13]

Anybody watching this in 2024 ?😅

[@bassycounter]

Yeah, trying to finish week 9 of CS50

[@julianfeezell1644]

This was an amazing series to watch. I used the python 12.2 and the updated libraries which had a few deviation and was fun to figure out how to get it working so i could get to the next step. I would love to see a continuation with the topics you had mentioned with a dev and production application with how we structured the code and unit testing. I am going to go check out the Django series next so I can see what it has to offer.

[@vigneshs9659]

I faced some issues while i was setting the flask_app variable using PowerShell and this fix worked for me: instead of using set FLASK_APP = flaskblog.py, try $env:FLASK_APP = "flaskblog.py"

[@RajanKumar-lv7ve]

thanks dude

[@pavaninaidu1483]

It still shows an error for me !

[@KhoiThinh]

My weekends are gonna be sacrosanct following these awesome tutorials. Thanks a lot Corey.