Most visitors can get an Indian e-Tourist Visa online in a few days. Here is the official portal, the visa lengths available, how early to apply, and what immigration will ask for on arrival.

Quick answer
Almost every foreign national needs a visa for India, and most can apply for an e-Tourist Visa online at indianvisaonline.gov.in without visiting an embassy. It is offered in 30-day, one-year and five-year versions. Apply at least four days before your flight (a week or more is safer), and carry a printout of the approval to show at immigration.
Sorting the visa is the one piece of Golden Triangle planning you have to do yourself, and it is easier than most people expect. This guide covers what our guests actually need to know; rules and fees change, so always confirm on the official portal before you apply.
Nearly all foreign nationals need a visa to enter India. A small number of countries have visa-free or visa-on-arrival arrangements, but travelers from Europe, the Americas, Australia, Japan and most of Asia apply in advance. The good news is that for tourism, the online e-Visa covers the vast majority of nationalities.
The Indian e-Visa for tourism comes in three lengths:
For a single Golden Triangle trip the 30-day visa is enough. If you think you will return within a year or two, the longer versions are often only slightly more expensive.
The government asks for applications at least four days before the date of arrival, and most approvals arrive within 72 hours. Our advice is to apply one to two weeks ahead so a request for clarification does not become a crisis. You can apply up to 120 days before travel for the 30-day visa.
Enter through a designated airport or seaport. Delhi (DEL) and Jaipur (JAI) are both on the list, as are Mumbai, Bengaluru, Chennai and the other major international airports. At immigration you will show:
Biometrics (fingerprints and a photo) are taken at the counter on first entry. Queues at Delhi can be long in the early hours when several long-haul flights land together, so build that into your first-day plan — we schedule airport pickups with this in mind.
Once the visa is done, everything else — the car, the guides, the tickets — is our job. If you are unsure whether your nationality qualifies for the e-Visa, message us and we will point you to the right page.
Private Golden Triangle tours run from Agra since 2004 by government-approved guides. Rated 4.9/5 by 403+ travelers on Google. Every article is written from what we see on the ground with guests every week.