Stack Exchange site names for API URL query parameter

You can query this using the API:

https://api.stackexchange.com/2.3/sites

Look for the api_site_parameter property in the output.

Find the documentation at Usage of /sites and the types it returns at Type Site.

What @rene says in the comments is absolutely the best advice:

From the docs in paragraph "Per-Site Methods" Each of these methods operates on a single site at a time, identified by the site parameter. This parameter can be the full domain name (ie. "stackoverflow.com"), or a short form identified by api_site_parameter on the site object. So https://api.stackexchange.com/2.3/answers?order=desc&sort=activity&site=webapps.meta.stackexchange.com works as well

I never heeded that advice, so I ended up with lots of exceptional cases in my scripts. Well, I probably needed such type of code anyway; try to guess the pattern for the iOS favicons for all sites from this URL: https://cdn.sstatic.net/Sites/stackoverflow/img/apple-touch-icon.png. And there's another system in the landscape with sometimes surprising identifiers; I posted about that here: How can I get URLs and site names for a cross-site SEDE query?

While @rene's solution is definitely the best way to go forward, if you want to insist on the original parameters:

1. For the main Stack Overflow site, use stackoverflow
2. If the host ends with .stackexchange.com, use its prefix
3. If the host ends with .stackoverflow.com, use its prefix and add .stackoverflow
4. Strip the .com suffix from the host (if it's present), and use the result.

Or use the one-liner from @Makyen's answer, since it's much easier. I tried to reverse engineer an algorithm based on a piece of code which (partially) does the opposite - no wonder it's not optimised.

As rene said in a comment, the documentation, under the "Per-Site Methods" heading, says:

Each of these methods operates on a single site at a time, identified by the site parameter. This parameter can be the full domain name (ie. "stackoverflow.com"), or a short form identified by api_site_parameter on the site object.

Getting the api_site_parameter from the /sites SE API endpoint

You can use the api.stackexchange.com site to compose test requests. For the /sites endpoint, a request which gets the site_url, api_site_parameter, and name for all sites can be seen here.

Computing the api_site_parameter from the site's canonical domain name

In addition, it's possible to compute the api_site_parameter value from the site's domain with simple string replacement. The following is valid code to get the api_site_parameter from the site's canonical domain name in at least Python and JavaScript. For other languages, adjust to the appropriate syntax:

domain.replace('.stackexchange.com', '').replace('.com', '')

will give you the api_site_parameter for all existing sites when using the canonical domain for the site, not an alias.

You can see site aliases with this SE API request. If you want to be fully complete, then you'll need to do a lookup based on the domain name, including all the aliases. However, most of the code I've seen ignores the aliases.

EDIT:

Erik has pointed out in the comments that the list is paginated so the below list is not the complete list. You can use the pagesize=5000 as suggested to get all the data. I have done the same thing in the following excel using the Excel Power Query to fetch data and create a table (for future reference).

Note: Download the excel and refresh the Power Query to fetch the data again. But do note that refreshing the Power Query consumes your API quota (max 300)

Thanks to @Erik's answer, below is the list of site names to be used in API extracted from the API - https://api.stackexchange.com/2.3/sites