A Tourist visa is given to those visiting India for tourism or other non-business related purposes. You should apply for a Tourist Visa only.
e-Tourist Visa Facility is available for some Nationalities of over 180+ countries. With the eVisa your landing airport is any of the designated Airports (i.e. Ahmedabad, Amritsar, Bagdogra, Bengaluru, Calicut, Chennai, Chandigarh,Cochin, Coimbatore, Delhi, Gaya, Goa, Guwahati, Hyderabad, Jaipur, Kolkata, Lucknow, Mangalore, Mumbai, Nagpur, Pune, Tiruchirapalli, Trivandrum, Varanasi & Vishakhapatnam) and 5 designated seaports (i.e. Cochin, Goa, Mangalore, Mumbai, Chennai). However, the foreigner can take exit from any of the authorized Immigration Check Posts (ICPs) in India.
The GopherConIndia organizers are happy to provide an invitation letter if you need one; we do suggest, however, that you check with your local embassy or consulate, as requirements differ from country to country. Do apply for your Indian Tourist Visa definitely by mid Oct. 2018