# Ecosystem Features All purchases of games, virtual items, and services on Gravity Hub are conducted using smart contracts that necessitate GVT tokens. Gravity's array of features, including loyalty programs, beta testing, bug reporting, and digital goods exchange, among others, exclusively operate with GVT tokens. GVT tokens are tradable within Gravity as well as on external markets due to their decentralized nature. By holding tokens in their wallet, users can download games and receive updates in a manner akin to popular platforms like Steam. Our user interface enables developers to tailor the services or privileges that their token confers upon other users. Some notable customizations for game tokens include: * Game access subscription. * Monthly game update subscription. * Permission for a second-hand market. * Referral programs for GVT tokens. * Additional referral programs for items. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://whitepaper.gravityhub.xyz/ecosystem-features.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.