Stop wasting money on CORS preflight requests. Here's a quick tip for reducing API Gateway costs. 👇 - ThreadSky

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theburningmonk.com • 52 days ago

Stop wasting money on CORS preflight requests.

Here's a quick tip for reducing API Gateway costs. 👇

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theburningmonk.com•52 days ago

Every time the browser makes a cross-origin request, it first makes a preflight request to make sure it can actually send the request.

Since API Gateway charges per request, you’re billed for both the preflight and the main request.

theburningmonk.com•52 days ago

Now, here’s the thing that surprises most folks.

Even if your API is hosted on a subdomain, e.g. https://api.example.com, the browser still sees it as a cross-origin request from https://example.com.

Moving the API to https://example.com/api will eliminate the need for preflight requests altogether.

theburningmonk.com•52 days ago

Of course, subdomains aren’t inherently bad, and many organizations prefer them to organize multiple APIs and environments. And maybe even let teams have their own subdomains and allow them to be more autonomous.

theburningmonk.com•52 days ago

But for personal projects or side hustles, where margins are tight, cutting these unnecessary costs can make a meaningful difference.

theburningmonk.com•52 days ago

You can also put CloudFront in front of your API and cache and handle these preflight requests at a lower cost. This doesn’t eliminate preflight request-related charges entirely, but it goes a long way to minimize it.

theburningmonk.com•52 days ago

If you liked this, then you might also enjoy the tips and tutorials I publish every week about AWS and serverless.

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