You need a tourist e-Visa to enter India. The application is done online, takes about an hour, and we recommend applying at least four weeks before you travel.
The website is a bit bumpy. If clicking "Next" does nothing, try your phone's browser instead. You'll also have to enter some information (passport ID, address) more than once, so plan in about an hour.
Take a screenshot of your Application ID during and after the process. You need it to log back in and to download your visa later.
And throughout the whole form: no umlauts or special characters (ä, ö, ü, ß) — the website can't handle them, so write ae, oe, ue, ss.
Once approved, the e-Visa arrives by email, usually within 1–2 weeks. You can also check the status and download it on the portal with your Application ID. Bring a printed copy for arrival, just to be safe.