SSO Sikkim is the single-window citizen-service portal of the Sikkim Government, run by the Department of Information Technology, Government of Sikkim. Through SSO Sikkim, citizens apply for, download and verify dozens of state-issued certificates — caste, income, domicile, residence, EWS, birth, death, marriage, OBC, SC/ST, agricultural-income, non-creamy-layer and many more. Each certificate carries a state-wide unique application reference number used as the verification key. The portal is integrated with the Common Service Centre (CSC) network of Sikkim, the Revenue Department's record-of-rights, and the State Treasury for fee payments. For mobile-first users, the equivalent SSO Sikkim mobile app surfaces the same services with biometric login. Helpline numbers and email addresses are published on the portal homepage.