Cross Origin Resource Sharing (CORS) - Explained with Example & Demo | API Gateway & Lambda

CORS (Cross origin Resource Sharing) can be confusing. In this video, we going to tackle it once and for all! We will learn the following. Timestamps given below as well.
1. What does Cross-origin mean?
2. What is CORS (Cross Origin Resource Sharing)?
3. What is CORS Pre-Flight?
4. How does CORS work with Amazon API Gateway?
5. Simple Vs Non-Simple Cross Origin
6. Multi origin CORS using Lambda
7. Demo for all the cases above!

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TIMESTAMPS
00:00 What is CORS
01:47 Simple Vs Non-simple CORS
02:50 CORS flow with preflight check explained (DON'T SKIP)
07:07 CORS Demo with API Gateway
15:50 Multi origin CORS with Lambda
21:14 Simple CORS API Demo

[cloudwithraj]

Timestamps added since we cover lot of stuff in this video. Hope this helps your viewing experience.

[mohammadikram]

Whenever i see your videos it's like jackpot of a knowledge. You are doing a great work sir🙏🙏❤️. I was confused about postman requests to my springboot Microservices in which we don't need any cors policy but now i know why we dnt need that.

[nickdube]

Thank you so much. I was struggling with the CORS error between my API and my S3 bucket for days until I watched your video. I really appreciate your work!

[snaidu]

Raj, all your explanations are very good. I cannot thank you enough.

[sardonyx_]

What a fantastic explanation of CORS with API Gateway! Thanks Raj!! I'm sharing this with my coworkers!

[betterwithrum]

I couldn't get mine to work until the last section demo where you showed adding the header. Nothing worked until I did that.

[Bollywood_evergreen_song]

I found it most useful video on CORS in youtube

[SahilKaironVlogs]

Great video Raj. It would have been a plus if you would have added about access control expose headers. I was a little confused with that.

[zaheer]

Thanks alot dude, You explanation was so easy to follow. i got the concepts now.

[-Altera-]

I still get an error for "Cross origin request blocked: the same origin policy disallows reading the remote resource at <insertResource> . CORS preflight response did not succeed (status code 500) and CORS request did not succeed (null)".

Been struggling with this for a while.

[pasumarthijahnavi]

I have created a load balancer for a service(spring). I am trying to use the balancer URL in my angular Proj. I am getting this Cros error. Is there any solution for this? In the spring service controller do I need to use cross-origin annotation and deploy in that particular environment (or) should I add anything else? Please help me with this :)

[fssalihb]

you saved my life thanks, very thourogh explanation

[carlosalvarez-cascos]

Good explanation, I followed your tips. Thanks.
Still I keep getting an error when requesting data from javascript to my aws REST api, with lambda in the backend. Things go well until I enable cache, still works from sometime and then it fails with your fetch "has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.". I just flush the cache and works again from different origins. Any idea?

[deepteshagrawal]

I am confused...how at the very first place...browser has sent a Preflight check when it was not enabled for non simple requests? while for Simple request demo...it didn't and the cors is also not enabled...then it should pass the request.

[ngneerin]

Please do a video on AWS HTTP API Gateway CORS, specially for cookies

[abhinavpratapsingh]

Can't we send array of origins in access control allow origin via integration response or lambda?

[harshverm]

Hi,
When I am enabling cors the all conditions are not passing some are failing.
What can I do in this case?
For you all passed.

[harithzainudin]

i really like the way you explain. from now onwards. looking forward for all of your video.. im new to aws and i watch a lot of your video to learn! please do more on explaination and tutorial! you get a like, subscribe and share from me! thank you so much :)

[PriThVi_RedDy]

@AgentofChange This is awesome. Can you also please share this sort of projects on Git. That is so helpful.

[rationalsage]

Nice video. Is there a book you read to learn this stuff?