Across Developer Documentation

# Across Protocol Documentation > Across Protocol is a crosschain interoperability protocol powering fast, low-cost token transfers across 23+ chains. > Three settlement mechanisms: Intents (relayer network), CCTP (USDC), and OFT (USDT). > API base URL: https://app.across.to/api ## Introduction - [Actors in the System](https://docs.across.to/introduction/actors): The key participants that make crosschain transfers work — users, relayers, LPs, dataworkers, and the UMA oracle. - [API Keys & Integrator ID](https://docs.across.to/introduction/api-keys): How to get an API key and integrator ID for production use of the Across APIs. - [Bug Bounty](https://docs.across.to/introduction/bug-bounty): Report vulnerabilities and earn rewards through the Across Protocol bug bounty program. - [Crosschain Live](https://docs.across.to/introduction/crosschain-live): Weekly livestream and podcast exploring crosschain interoperability with builders, founders, and community members from across Web3. - [Deposit Addresses](https://docs.across.to/introduction/deposit-addresses): Generate a counterfactual deposit address that users can send funds to in order to initiate a crosschain transfer. - [Direct Route Linking](https://docs.across.to/introduction/direct-route-linking): Link users directly to a pre-filled bridge route on the Across UI. - [Technical FAQ](https://docs.across.to/introduction/faq): Frequently asked questions about integrating Across Protocol. - [Key Features](https://docs.across.to/introduction/features): What makes Across the fastest, cheapest, and most secure crosschain interoperability protocol. - [Fees in the System](https://docs.across.to/introduction/fees): How LP fees, relayer fees, gas fees, and capital fees are calculated in Across. - [Working with Hypercore](https://docs.across.to/introduction/hypercore): Bridge assets to Hyperliquid's sub-second settlement layer via Across. - [Welcome to Across](https://docs.across.to/introduction): Crosschain interoperabil