online gehen

Grammar-wise, it functions as a separable-style verb phrase. You conjugate gehen and keep online as the modifier. In a main sentence, it looks like: Ich gehe online. If you are using a modal verb, it stays together: Ich muss kurz online gehen. It is as flexible as your favorite pair of jeans. You can use it for your computer, your phone, or even your smart fridge.

You will use this constantly in daily life. Use it when you are looking for a Wi-Fi password at a café. Use it at work when a new marketing campaign is ready. It is perfect for telling a friend you will meet them in a video game. It works well when your internet is acting up and you are trying again. It is the bread and butter of modern German communication.

Don't use it if you are already connected and just browsing. In that case, use im Internet surfen. Avoid it if you are talking about 'logging in' to a specific app. For that, einloggen is the more precise choice. It sounds a bit robotic if you use it for 'checking your phone' quickly. Don't say it when you are just turning on your computer without internet.

Germany has a complicated relationship with being 'online'. Digitalization has been a slow-moving train in many rural areas. Because of this, online gehen sometimes carries a sense of relief. You might hear people complain about 'Funklöcher' (dead zones) where they can't online gehen. It became part of the standard vocabulary in the late 90s. Now, even your grandma likely uses it for her iPad.

You might hear ins Netz gehen as a slightly more 'techy' alternative. Some people also say online sein to describe the state of being connected. If something is published, people say es ist online gegangen. This treats the website or article like a person stepping onto a stage. It is a very active, movement-oriented way to describe digital presence.