Why Devs and Builders Choose Across for Crosschain Infrastructure in 2026

TL;DR: With 100+ Layer 2 and Layer 3 chains tracked by L2Beat, every application needs reliable crosschain infrastructure. Across is the fastest crosschain bridge protocol, delivering ~2-second fills, $35B+ bridged with zero exploits, and native support for AI agents via skills.across.to. Whether you're building a DeFi protocol, a wallet, or an autonomous agent, the Across Swap API gets you live in under an hour. Start at docs.across.to.

Two years ago, the question was whether we'd end up with too many chains. L2Beat now tracks over 100 Layer 2 and Layer 3 networks, and every one of them has users, liquidity, and applications that need to talk to every other chain. The math is simple and unforgiving: every new chain doesn't add one bridging problem—it multiplies the number of possible routes across the entire network.

If you're a developer building anything that touches more than one chain, crosschain infrastructure isn't optional. It's load-bearing. And the protocol you choose to build on determines your speed, your security, and whether your integration takes a week or an afternoon.

Here's why teams building crosschain applications, wallets, DeFi protocols, and AI agents are choosing Across.

Every new chain that launches creates another fragmentation challenge that compounds quadratically. Your users' USDC is on Arbitrum. The protocol they want is on Base. The yield is on HyperEVM. None of these chains know the others exist unless your application connects them.

The original L2 thesis was tidy: a handful of rollups, each handling a niche, all settling back to Ethereum. What actually happened was an explosion of general-purpose rollups, app-specific chains, L3s built on L2s, and non-EVM networks joining the crosschain conversation. Developers who hardcoded a single chain are now scrambling to go multichain. Developers who planned for multichain from day one need infrastructure that scales with the ecosystem.

This is the problem Across was built to solve—and why its architecture matters for every developer evaluating crosschain bridge solutions.

The lock-and-mint bridge architecture that dominated 2020–2022 had a structural flaw: it concentrated user funds in smart contracts protected by validator networks or multisigs. When attackers found the weak point—compromised validators, logic bugs, social engineering—they drained the pool. Ronin ($625M), Wormhole ($320M), and Nomad ($190M) were the result. The honeypot problem wasn't incidental. It was architectural.

Across pioneered the intents-based model that replaced it. Here's how it works: you sign an order describing what you want ("I have 1,000 USDC on Ethereum and I want 1,000 USDC on Arbitrum"). Professional relayers compete to fill that order, fronting their own capital on the destination chain. You get your tokens in approximately 2 seconds. The relayer gets reimbursed after settlement verification. Your users' funds are never locked in a vulnerable pool.

This is why Across has processed $35B+ in crosschain volume and 15M+ transactions with zero exploits across its entire operating history. The architecture removes the honeypot. There's no user-funded pool to drain.

The Across Swap API is the unified entry point for all crosschain operations. Integration is three steps:

That's it. Teams regularly go from first API call to production in under an hour. The full endpoint documentation, parameter schemas, and code samples are at docs.across.to.

Beyond basic bridging, the Swap API supports embedded actions—custom on-chain operations that execute immediately after a crosschain swap lands. Bridge USDC to Base and deposit it into a lending protocol in a single user transaction. Bridge ETH to Arbitrum and swap it into a specific token on arrival. This composability is what makes Across the preferred crosschain infrastructure for DeFi protocols building multichain experiences.

Across also supports ERC-7683 intents via AcrossOriginSettler, direct route linking for pre-filled bridge routes without API calls, counterfactual deposit address generation for deterministic deposits, and multiple settlement pathways (optimistic verification via UMA, CCTP V2 for native stablecoin transfers, and OFT support) optimized for speed, cost, and transfer size.

Across currently supports 26 mainnet chains: Ethereum, Arbitrum, Optimism, Base, Polygon, BNB Smart Chain, zkSync, Linea, Scroll, Blast, Mode, Lisk, Zora, Ink, Unichain, Soneium, World Chain, Lens, Lighter, Tempo, HyperCore, HyperEVM, MegaETH, Monad, Plasma, and Solana. Each new chain Across adds is another route your application can offer without changing a line of integration code.

The Swap API abstracts chain-specific complexity. You don't need to manage RPCs, gas tokens, or bridging quirks for each network. One API, one integration, every chain.

AI agents are a new class of crosschain user that nobody planned for—and Across has built native agent support into the protocol. Autonomous agents executing DeFi strategies need to bridge tokens between chains programmatically, without human intervention. They need single-call APIs that return deterministic results and structured tool definitions their frameworks can consume.

Across built skills.across.to specifically for this. It's a knowledge base and tool registry that teaches AI systems how to build with Across. Agents can:

There are four ways to integrate. You can paste a skill URL directly into your agent's context and ask it to build with Across. You can fetch any skill file via curl—all files have CORS enabled. You can install the persistent Claude Code skill with /skill add across-protocol-ai-agent-skill. Or you can connect to the MCP server at mcp.across.to/mcp for live quotes, swaps, tracking, and chain/token queries. The skills CLI (npx skills add https://github.com/across-protocol/skills --yes) works with Claude Code, Codex, Cursor, and Openclaw. The MCP server is compatible with Claude Desktop, Claude Code, Cursor, VS Code Copilot, Windsurf, and Codex.

An agent can process "Bridge 100 USDC from Arbitrum to Base" and independently handle route selection, token lookups, quote retrieval, approvals, and execution. No human intervention required. This is the interface autonomous DeFi agents need.

Bridge exploits during 2021–2023 resulted in some of the largest losses in DeFi history. The pattern was consistent: lock-and-mint bridges concentrated user funds in smart contracts, attackers found the weak point, and billions were drained. The intents-based architecture Across pioneered addressed this by removing the honeypot entirely.

Across's zero-exploit record at $35B+ in volume is the strongest evidence that this architectural bet paid off. The protocol has undergone 8 audits and maintains a $1M bug bounty. Settlement verification through UMA's Optimistic Oracle adds a verification layer without adding latency—fills are assumed valid unless challenged within a dispute window. Fast for the common case, protected for the edge case.

For developers, this means you can integrate Across knowing your users' funds aren't sitting in a vulnerable pool. The security model is structural, not dependent on a multisig or validator set you have to trust.

Ready to integrate? Here's where to start:

Across is the fastest crosschain bridge protocol, delivering ~2-second fills across 26 chains with $35B+ bridged and zero exploits. The Swap API enables integration in under an hour with full endpoint documentation at docs.across.to.

Intents-based bridging lets users sign an order describing what they want (e.g., "send 1,000 USDC from Ethereum to Arbitrum") while professional relayers compete to fill that order using their own capital. This architecture, pioneered by Across, shifts risk from users to relayers and eliminates the vulnerable liquidity pools that led to major bridge exploits.

ERC-7683 (Crosschain Intents) is a crosschain intents standard co-authored by contributors from Across and Uniswap. It defines a shared order format and settlement contract interfaces for crosschain transactions that any compliant solver or relayer network can fill. Across supports ERC-7683 natively via AcrossOriginSettler.

Across has built native AI agent support into the protocol. Through skills.across.to, agents can access structured tool definitions, an MCP server, and skill files that enable autonomous crosschain operations—bridging tokens, getting live quotes, executing swaps, and composing embedded actions without human intervention.

Across supports 26 mainnet chains: Ethereum, Arbitrum, Optimism, Base, Polygon, BNB Smart Chain, zkSync, Linea, Scroll, Blast, Mode, Lisk, Zora, Ink, Unichain, Soneium, World Chain, Lens, Lighter, Tempo, HyperCore, HyperEVM, MegaETH, Monad, Plasma, and Solana.

Across has been building crosschain infrastructure since the beginning—$35B+ bridged, zero exploits, ~2-second fills, and the standard (ERC-7683) that's shaping what comes next. Start building at docs.across.to. For AI agent integration, visit skills.across.to.