Category: Cross-chain intents / bridge / interoperability API infrastructure
Summary: Across is a cross-chain interoperability protocol centered on intents-style asset movement and embedded destination-chain actions. The useful read is not bridge UI with better branding; it is an app-facing routing layer with relayers, APIs, refund logic, and multiple settlement paths packaged behind one surface.
What it does:
Provides a consumer bridge/swap interface plus developer-facing APIs for cross-chain swaps, bridging, and embedded actions
Uses an intents-style model with competitive relayers and a modular three-layer system covering RFQ, relayer execution, and settlement
Routes transfers through multiple settlement pathways, including intent-based fills as well as USDC/CCTP and USDT OFT flows documented in official materials
Exposes operational docs for API keys, fee mechanics, deposit tracking, refunds, relayer participation, bug bounties, and security verification
Maintains public smart-contract, relayer, SDK, and related infrastructure repositories
Key claims:
Official site says Across is “Powered By Intents” and presents itself as a production interoperability system with $22B+ volume, 15M+ transactions, and sub-minute average fill times
Official docs say Across provides cross-chain interoperability with ~2 second fills across 23+ chains and powers swaps, bridges, and embedded actions through a unified API, which is why this note belongs at the routing layer rather than at the trust-anchor layer
The docs llms.txt index shows a notably broad operating surface: actors, fees, refunds, stablecoin pathways, relayer docs, deposit tracking, embedded actions, bug bounty, and security/verification pages
Security docs say Across uses optimistic verification secured by on-chain contracts, ABT bonds, challenge periods, and UMA’s oracle/DVM process rather than a traditional validator-set bridge model
Public GitHub materials show Across shipping contracts, a relayer stack, SDKs, and adjacent infra repos including an MCP server, reinforcing that the project operates as a developer-facing interop control plane rather than only a frontend bridge
Whitepaper: No classic whitepaper or litepaper was found in this pass. The strongest primary materials were the official site, docs portal, docs llms.txt index, security docs, and public GitHub organization; see ../whitepapers/across-primary-sources-2026-04-25.md.