Relay: Instant, Low-Cost Cross-Chain Transactions on Solana

TLDR

Relay is a cross-chain payments system built on Solana that enables instant, low-cost bridging and cross-chain execution. It connects users with relayers who act on their behalf across chains in exchange for a small fee. By minimizing gas costs and execution latency, Relay is ideal for price-sensitive applications like payments, trading, NFT mints, and gas abstraction.

How Relay Works

At its core, Relay is designed to make cross-chain transactions as fast and cheap as possible. It achieves this through a few key innovations:

1. Connecting Users and Relayers - When a user wants to bridge assets or execute a transaction on another chain, they receive a quote from a relayer. The user accepts the quote and sends the assets to the relayer, who validates the transaction and sends the funds to the user on the destination chain. Relayers maintain balances on all supported chains to enable this flow.

2. Minimizing Gas Costs - Relay splits a cross-chain transaction into three components: the asset transfer, order validation, and fee collection. While the asset transfer happens on the (usually expensive) origin and destination chains, the order validation and fee collection are performed on a cheaper settlement layer. This minimizes gas paid on expensive chains.

3. Direct Transfers - Asset transfers in Relay are done directly between the user and relayer. This is more efficient than routing through complex AMMs or liquidity pools like many bridging solutions. Direct transfers combined with offchain order validation reduces gas costs to the absolute minimum.

4. Single Relayer Architecture - Unlike systems that require consensus between multiple parties, Relay transactions are executed optimistically by a single relayer. This allows for extremely fast transaction confirmation, with small transfers completing in seconds. Relayers put up bonds that can be slashed if they misbehave.

Relay's Unique Multi-Chain Approach

Another key aspect of Relay is how it approaches multi-chain expansion. Many cross-chain systems require substantial work to add support for a new chain, such as deploying contracts, establishing consensus, and creating liquidity pools.

In contrast, Relay has a uniquely lightweight and flexible model. To add support for a new chain, all that's needed is a single relayer willing to operate there - no smart contracts, consensus, or pools. This is ideal for a future with dozens or hundreds of relevant chains.

Any relayer can begin supporting a new chain permissionlessly, simply by maintaining a balance there to receive and send user funds. Relay plans to fully open the relayer system with the trustless Relay Protocol (more on this below), enabling an open marketplace of relayers competing on speed, price, and supported chains.

Use Cases Powered by Relay

Relay's speed and low costs enable a variety of powerful applications:

Instant Bridging

Relay offers the fastest bridging experience in crypto, with confirmations in seconds for transfers under $1000. Compared to alternatives, Relay cuts fees by 80% or more by minimizing expensive on-chain operations. Instant, cheap bridging is essential infrastructure for a multi-chain ecosystem.

Cross-Chain Trading & Liquidity

Beyond basic bridging, Relay enables seamless swaps between any supported assets across chains. Relayers source liquidity from DEXes on both sides of a trade to provide an aggregated quote. Swap fees are drastically reduced by performing the actual asset exchange off expensive chains.

Gas-Free Mints & Sends

Relay can subsidize transaction costs for users, enabling gas-free NFT minting and token transfers. This is especially valuable for onboarding mainstream users uncomfortable paying gas. The relayer covers the transaction fee upfront and collects repayment in the user's token of choice later.

Cross-Chain Account Abstraction

Account abstraction (AA) separates the "signing" and "paying" roles in a transaction, allowing wallets and dapps to subsidize gas for users. Relay extends AA cross-chain, so an account on one chain can sponsor transactions for a user on another. This unlocks novel UX flows and business models.

The Relay Protocol (Upcoming)

Today, Relay is powered by a single relayer, Reservoir, who handles all liquidity provision and order execution. While this creates a great user experience, it introduces centralization risk.

The upcoming Relay Protocol will address this by establishing an open, trustless network of relayers. Relayers will put down stake to participate. Their stakes will be slashed if they misbehave, but they'll earn fees on volume they process.

The protocol will feature a request-for-quote system where users can solicit bids from relayers and choose the best combination of price and speed for their needs. Relayers will compete to provide the best pricing and service.

Longer term, the protocol can accommodate different types of relayers for different use cases - for example, some optimizing for speed and others for cost. This specialization and competition between relayers will ensure users always have access to the best possible bridging and cross-chain experience.

Conclusion

Relay is a powerful new primitive for cross-chain interactions, leveraging Solana's high speeds and low costs. Its architecture allows for ultra-fast, ultra-cheap bridging and execution across chains, with a uniquely simple model for multi-chain expansion.

As crypto becomes increasingly multi-chain, Relay is positioned to be a critical piece of infrastructure. It drastically improves the UX of using multiple chains while reducing costs for dapps and users. And with the upcoming Relay Protocol, it will transform into an open, robust network equipped to scale to meet demand.

Whether it's trading, bridging, minting NFTs, or sending tokens to friends, Relay offers the easiest and most affordable way to traverse chains. As more users and dapps integrate Relay, it has the potential to be a unifying layer connecting disparate ecosystems into one interoperable network.