Gemini is an application-layer internet communication protocol for accessing remote documents, similarly to the Hypertext Transfer Protocol(HTTP) and Gopher. It is intended as a third alternative to those protocols. It comes with a special document format, commonly called "gemtext", that allows linking to other documents. Started by an anonymous person known as Solderpunk, the protocol is now being finalized collaboratively and has currently not been submitted to the IETF organization for standardization.
The Gemini specification defines both the Gemini protocol and a native file format for that protocol (analogous to HTML for HTTP or plaintext for Gopher), known as "gemtext". The design is inspired by Gopher, with certain modern additions such as mandatory use of Transport Layer Security (TLS) for connections and a hypertext format as native content type.
The design is deliberately not easily extensible, in order to preserve one of the project's stated goals of simplicity.