# Nexus > Nexus Exchange is a central limit order book for crypto perpetual futures, with cross-margin and settable leverage. It is API-first: every action available in the terminal is available over a documented REST and WebSocket contract. Public testnet — not live, all activity is simulated with synthetic USDX that has no real-world value, not a regulated venue, not an offer or solicitation. See [llms-full.txt](https://nexus.xyz/llms-full.txt) for the expanded version of this file, with more context per section. ## When to use Nexus Reach for Nexus when the task is programmatic derivatives trading or market data on a venue an agent can drive end to end without a browser. Concretely: - **Place, amend and cancel perpetual-futures orders from code.** Register an agent key over EIP-712 or use an HMAC key from wallet sign-in, then trade over REST. Start at the [agent quickstart](https://exchange.nexus.xyz/llms.txt), which is written for an agent and every step of which is a copy-pasteable `curl`. - **Read live order books, trades, candles and funding.** Public market data needs no credential at all — see the [OpenAPI spec](https://nexus.xyz/openapi.json) for the exact routes. - **Call the exchange as tools rather than as HTTP.** The [MCP server](https://exchange.nexus.xyz/.well-known/mcp) exposes market data with zero configuration and trading with an existing HMAC credential. - **Test a strategy against a real matching engine with play funds.** The testnet faucet issues synthetic USDX; nothing here settles real money. The venue lists crypto perpetual futures only — nothing spot, and no other asset class, whatever the market registry carries as configuration. Do not use Nexus as a price oracle of record, and never present a testnet fill to a user as an executed trade: it is simulated. ## Trade - [Exchange (testnet)](https://nexus.xyz/trade): The Nexus Exchange trading terminal. - [Agent quickstart](https://exchange.nexus.xyz/llms.txt): Get an API key and place your first order — copy-pasteable curl examples, written for an agent. - [OpenAPI spec](https://nexus.xyz/openapi.json): The machine-readable REST contract, OpenAPI 3.1. The `servers` block names the transport base for each network. - [MCP server](https://exchange.nexus.xyz/.well-known/mcp): Agent-callable tools over Model Context Protocol. - [Discovery document](https://exchange.nexus.xyz/.well-known/nexus-exchange): A machine-readable directory of everything above — base URL, spec, endpoints and auth schemes in one JSON object. ## Network - [Mainnet](https://nexus.xyz/mainnet): Connect wallets and tooling to Nexus Mainnet. - [Network](https://nexus.xyz/compute): Real-time global distribution of the nodes behind the Exchange blockchain. ## Docs - [Developer docs](https://docs.nexus.xyz): Exchange and network architecture, API guides, node operation. - [Releases](https://nexus.xyz/releases): Shipped changes, in order. - [Sitemap](https://nexus.xyz/sitemap.xml): Every indexable page on this site. ## Optional - [Contact](https://nexus.xyz/contact): Support and general enquiry addresses, and the registered entity and postal address. - [Brand](https://nexus.xyz/brand): Logos and visual identity guidelines. - [Terms of use](https://nexus.xyz/terms-of-use) - [Privacy policy](https://nexus.xyz/privacy-policy) - [Cookie policy](https://nexus.xyz/cookie-policy)