Just before every patch, vehicular-combat MMO War Thunder opens its development (dev) server for the public. Perhaps for the developers to get the feel of the current state of the game alongside its base players or for some other reason – nevertheless, this happens one or two times every patch.
But how exactly do you go there? Do you need another login account specifically just to access the dev server? Can you use your Steam login instead? Let us answer that for you.
Can You Use A Steam Login On The War Thunder Dev Server?
The short answer here is yes, assuming that you have already linked your Steam ID with your Gaijin account.

Back in the 1.61 update, the option to link your Steam ID with a Gaijin account has been added to the in-game profile for those who may have created a separate login on Steam without prior registration at Gaijin.net.
Take note that without the Gaijin account, you would not be able to utilize the game’s customer support, forum, or even make in-game purchases. After all, Gaijin is the developer of War Thunder.
You can easily link your Steam ID to a Gaijin account by simply clicking on your nickname at the top of the hangar and clicking the option to link accounts.
Just make sure that you aren’t using an e-mail that has previously been used for a separate Gaijin account.

Now that your Steam ID and Gaijin account are linked and are practically one and the same, you may now freely enter the War Thunder dev server using your Steam login.
Lastly, keep in mind that you are basically redownloading the entire War Thunder game when downloading the dev server launcher.