The promise of a modular, multi-rollup future on Ethereum is here, but its potential has been constrained by a heavily fractured user and developer experience. Traditional bridging solutions present a complex web of unreliable transfer speeds, security models, and confusing wrapped assets. For developers, this translates into significant engineering overhead, forcing them to integrate multiple point solutions and build bespoke infrastructure rather than focusing on their core applications. The result is a landscape of siloed ecosystems that undermines the vision of a seamlessly interconnected network of blockchains.
This challenge requires a fundamental change in how we approach interoperability. The solution lies in shifting from an imperative model, where users and dApps must specify every step of a cross-chain transaction, to a declarative model powered by intents. An intent is a cryptographically signed message where a user simply declares their desired outcome (e.g., "I want 100 USDC on Arbitrum, and I will provide 0.05 ETH on Base to cover it"), leaving the complex execution path to a network of specialized solvers.
With the launch of The Metalayer Mainnet Beta, Caldera is introducing a robust, shared interoperability solution engineered to orchestrate intent-based cross-chain interactions for the entire rollup ecosystem. The Metalayer's sophisticated solver ecosystem and secure messaging layer are leveraged to deliver reliable, efficient, and secure cross-rollup interoperability.
The Metalayer Architecture: The Intent Orchestration Engine
Drawing from Caldera’s unique vantage point of powering over 25% of all Ethereum rollups, The Metalayer is not just another interoperability protocol. It's a comprehensive, vertically integrated framework designed to abstract away complexity at every level. It achieves this by intelligently orchestrating best-in-class, off-the-shelf solutions from partners like Across, Relay, and Eco for execution, while leveraging a sovereign deployment of Hyperlane’s battle-tested technology for secure settlement messaging.
The architecture is composed of three core components:
1. The Execution Layer (The "Brain")
The Execution Layer is The Metalayer's brain. When a user or dApp expresses an intent via The Metalayer SDK or the white-label bridge UI, the Intent Routing Network gets to work.
Quote Aggregation & Optimal Path Selection: For each intent, The Metalayer queries all integrated solver networks (like Across, Relay, and Eco) in real-time to receive quotes for fulfilling the user's request. It then aggregates these quotes and presents all available routes to the user, with a suggested default. In the Mainnet Beta, the default route is optimized for speed. In the future, this will evolve to a "best" route, representing an optimal balance of speed and cost efficiency. Users always retain the ability to select any of the available routes presented.
Ready-to-Sign Transactions: A key feature of The Metalayer's Developer Toolkit is that once a quote is accepted, our SDK provides the developer with the full, formatted calldata (the low-level instructions for the transaction) required to initiate the intent on-chain. This abstracts away all underlying partner-specific protocol complexities; the dApp developer only needs to pass this data directly to the user's wallet for a signature. All subsequent status polling is handled internally by the SDK, providing real-time updates to the dApp's frontend without additional developer effort.
2. The Solver Ecosystem (The "Muscle")
The Metalayer collaborates with and directs intents to a variety of fulfillment networks, including both leading external partners and Metalayer-specific solvers.
Defining Solvers/Fillers: These are specialized entities participating in partner networks (Across, Relay, Eco) or the Metalayer's own network that monitor for intents and compete to fulfill them.
Mechanism of Fulfillment: Typically, a solver will "fast-fill" an intent by using their own capital on the destination chain to instantly deliver the desired assets to the user. The user receives their funds in seconds, while the solver temporarily takes on the risk associated with the cross-chain settlement lag. This solver-driven model enables high-speed transfers. While any intent system relies on a healthy, decentralized network of solvers to prevent centralization risks, The Metalayer is designed to aggregate multiple, distinct solver networks, enhancing resilience.
3. The Settlement Layer (The "Backbone")
After a solver fulfills an intent, a secure mechanism is needed to ensure they are correctly reimbursed from the user's escrowed funds on the origin chain. To orchestrate this complex process, The Metalayer's Settlement Layer is built on top of a sovereign deployment of Hyperlane’s battle-tested messaging technology. This provides a secure and reliable cross-chain messaging backbone, operated with our own independent network of validators and relayers, tailored specifically for The Metalayer ecosystem. For developers, this means it is critical to interact exclusively with The Metalayer's router contract and addresses to ensure messages are correctly routed and settled within our network, rather than referencing any public Hyperlane contracts that may also exist on-chain.
The Flow: When a solver fulfills an intent on the destination chain, The Metalayer's Inbox contract logs this action. The MetaProver component (service for verifying fulfillment) on the destination chain then constructs a "proof of fulfillment" message and dispatches it via the network's on-chain Mailbox.
Secure Delivery: A Hyperlane Relayer transports this message to the source chain, where it is securely processed by the source chain's Hyperlane Mailbox.
Standardized Proof, Diverse Settlement: This Hyperlane message acts as a standardized "proof of Metalayer-facilitated fulfillment." The IntentSource contract (the on-chain registry for user intents) on the source chain receives this verified proof and marks the intent as completed. This action then enables the original solver to claim their reimbursement from the user's funds held in the Vault, reconciling the transaction. This orchestration works seamlessly whether the fulfillment was by Across (which uses UMA for its internal settlement), Relay (which uses direct rebalancing), or Eco (which utilizes The Metalayer's MetaProver as a valid prover within its system), because The Metalayer standardizes the proof of fulfillment messaging layer.
Configurable Security: The Metalayer's Approach to Trust
Security is the foundational principle of The Metalayer. The architecture has completed rigorous security audits by Halborn, and it's designed to be robust and reliable.
A key aspect of The Metalayer's security model is configurable finality, which leverages Hyperlane's Interchain Security Modules (ISMs) (customizable on-chain rulebooks for verifying messages) under the hood. Instead of requiring developers to understand and implement arbitrary ISMs, a complex task, The Metalayer abstracts this into a simple, powerful choice between pre-configured security levels for messages:
Fast Finality (Default): This option considers a message settled as soon as the source transaction is included in a block (effectively first confirmation on most rollups). This offers the lowest latency and is ideal for the vast majority of applications.
Finalized: This option waits for the source transaction's block to be fully finalized on its L2, protecting against reorgs. This provides higher security guarantees for high-value transfers or security-critical applications at the cost of increased latency.
This approach gives developers a direct and meaningful choice, allowing them to explicitly manage the trade-off between latency and security guarantees. As an orchestration layer, The Metalayer's overall resilience is also a function of the underlying solver and messaging networks. We actively monitor the health of our integrated partners and design the routing logic to favor reliability, while the sovereign messaging layer prevents single points of failure.
As the underlying infrastructure evolves (e.g., to include ZK proofs or restaking-based security), Caldera can upgrade these security modules, and applications using The Metalayer will automatically benefit without requiring code changes on their end. This is a core tenet of the "future-proofing" guarantee.
Use Cases in Action: What The Metalayer Unlocks Today
Instant Bridging: The core use case for fast, efficient asset transfers, powered by our aggregation of leading solver networks.
Composable Actions (Bridge + Call): The Metalayer's Mainnet Beta already supports a limited scope of composable intents. If an underlying solver partner like Relay or Eco supports executing arbitrary calldata (e.g., bridge AND mint NFT), The Metalayer's IntentSource and Inbox contracts are equipped to pass these instructions through. The primary focus at launch is on perfecting these flows through deep, custom integrations. Over time, we will expand these capabilities to allow developers to more generally propose and execute sophisticated multi-step execution plans through The Metalayer's SDK.
The Caldera Advantage: Native Interoperability for Rollups
Day-Zero Connectivity: Every Caldera-launched rollup comes with The Metalayer automatically deployed, solving the "cold-start" problem of liquidity and user access from the moment of launch.
Future-Proofing: Caldera manages the interop stack. As better solvers or messaging technologies emerge, Caldera integrates them into The Metalayer, and all connected rollups benefit without needing to re-integrate or migrate. This protects developers from being locked into a single solution that may become obsolete.
Designed for Rollups: While general-purpose protocols like Hyperlane are designed for maximum extensibility, The Metalayer is opinionated and specifically optimized for the needs of rollup ecosystems, providing secure, out-of-the-box configurations that work from day one.
The Future: Intents as the Engine for the "Internet of Chains"
The launch of The Metalayer Mainnet Beta marks a significant milestone in our journey towards a future of 10,000 seamlessly interconnected rollups. By abstracting complexity and orchestrating a competitive ecosystem of solvers, The Metalayer provides the foundational infrastructure needed to make this "Internet of Chains" a tangible reality.
This isn't just Caldera's solution; it's a collaborative effort with our partners and the community to build a more unified, efficient, and powerful blockchain ecosystem for all participants.
We invite you to explore our documentation, experiment with our SDK, and begin building the next generation of truly cross-chain applications.
Integrate The Metalayer: Access our Mainnet Developer Documentation at docs.caldera.xyz.
Launch Your Interconnected Rollup: Learn more about deploying a high-performance rollup on the Caldera platform for instant Metalayer connectivity here.
Get Support: Join our dedicated developer channels on Discord for technical support.
The interconnected future of rollups is being built today. Join us.
About Caldera
Caldera is one of the fastest-growing rollup ecosystems on Ethereum, empowering web3 teams to launch high-performance, customizable, application-specific rollups. Dozens of leading EVM chains, including Manta, Apechain, Kinto, Injective, RARI Chain and Zero Network by Zerion, use our trusted Rollup Engine to enjoy unified connectivity with rollups across all leading frameworks via the Metalayer.
