> For the complete documentation index, see [llms.txt](https://docs.nexus.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nexus.xyz/overview/usdx.md). # Dollar balances How money works on the Exchange: dollar balances, and what USDX means where you see it. Balances, margin and profit and loss on the Nexus Exchange are in dollars. One balance backs every position you hold. **USDX is the dollar unit the Exchange accounts in.** One USDX is one US dollar. You see it in market identifiers such as `BTC-USDX-PERP` and in API fields that carry a balance or a price. ## On testnet Testnet balances are synthetic USDX from the faucet, which has no real-world value. See [Exchange testnet](/overview/exchange-testnet.md) to claim them. ## Learn more See [Margining](/trading/trading/perpetuals/margining.md) for how collateral and leverage work, and [Quickstart](/trading/trading/quickstart.md) to fund an account and place your first order. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.nexus.xyz/overview/usdx.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. 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.