Berlin is where the sandwich version is dated to, early 1970s, Turkish guest workers, Kreuzberg. That is the origin story. It is not the whole country.
Germany has more than 16,000 döner shops. Berlin has a dense share of them. Every other city has the sandwich too: Hamburg, Cologne, Munich, Frankfurt, the Ruhr. It overtook the burger and the bratwurst as the everyday fast meal nationally, not as a Berlin curiosity.
What stays the same
The spit. Toasted flatbread. A vegetable pile. Sauce. Eaten standing, or at a high table, often in paper, often late. The imbiss — a small counter, a window, no dining room — is the shop. That shape is German, wherever the shop is.
What moves
Bread. Pide and sesame fladenbrot are the Berlin tell. Some regions lean harder on one than the other. A durum wrap sits next to the sandwich almost everywhere.
Sauce. The yogurt-garlic, herb and chili trio is what English-language explainers mean by “German döner sauce.” Shops vary. Some cities run hotter. Some run a single white sauce. The trio is the classic, not a law.
Meat. Veal is more common in some classic Berlin shops than in the rest of the country. Chicken and mixed have grown everywhere. Lamb never disappeared.
The box. A Teller or a box — the sandwich taken apart, on salad or fries or rice — is how you eat it with a fork, or without bread. It is German, not an American invention. Fries next to kebab have been on the counter for decades.
What is not German döner
A seated restaurant with kebab on a long menu. Waffle bread. A 2,000-square-foot dining room. A warehouse cone bound with wheat and soy. Those exist in Germany too, because every popular food gets a cheap version. They are not the sandwich the 1970s shop made.
If you are trying to tell whether a US shop is this food, the test is the German one: small box, spit in the window, toasted bread, vegetables as the volume, eaten standing.
The country, not the neighbourhood
Berlin started it. Germany eats it.
Sixteen thousand shops is a national habit. The sandwich version is Berlin-born. The customers are everywhere.