Fast Protocol is the only swap on Ethereum that confirms before the block.

When you swap tokens through most Ethereum interfaces, you submit a transaction and wait. You wait for a builder to include it in a block, for a proposer to propose that block, and for the network to finalize it. That takes 12 seconds at minimum, often longer. During that window, your transaction is visible in the mempool, exposed to mev extraction, and you have no guarantee it will land where you expect.

Fast Protocol changes this. Swaps confirm in roughly 200 milliseconds.

How it works

Fast Protocol is an order flow auction (OFA) built on the mev-commit preconfirmation protocol. Here's the flow:

1. You submit a swap through the Fast Protocol interface
2. Your transaction routes through FAST RPC to the mev-commit network
3. Block builders compete for the right to include your transaction in an open auction
4. The winning builder issues a cryptographic preconfirmation — a signed commitment to include your transaction at a specific position in the next block
5. You receive confirmation in ~200ms, before the Ethereum block is even produced
6. Your swap settles on-chain in the next Ethereum block, exactly as committed

The preconfirmation isn't a promise. It's a cryptographic commitment backed by the builder's slashable stake on mev-commit. If the builder fails to deliver, they lose real money.

Who benefits

Traders get sub-second confirmation and mev protection. Instead of watching a pending transaction spin and hoping it lands favorably, you know within 200ms that your swap will execute at the price you expect.

Users who generate mev get rewarded for it. Every swap creates mev — the value generated by the ordering and inclusion of transactions. On most platforms, searchers and builders keep that value. On Fast Protocol, at least 90% comes back to you.

Builders gain access to exclusive order flow. By participating in the auction, builders get high-quality transactions that improve their block value. The auction is competitive, so builders are incentivized to offer the best execution to win.

Validators who opt in to mev-commit see significantly higher rewards. By committing to propose mev-commit blocks, validators access a share of the preconfirmation fee market on top of their standard block rewards.

What makes this possible

Three technical components work together:

• mev-commit protocol: The credible commitment layer that enables preconfirmations. Builders stake collateral and make cryptographic commitments to include specific transactions. Breaking a commitment triggers slashing.
• FAST RPC: A drop-in Ethereum RPC endpoint that routes your transactions through the mev-commit auction instead of the public mempool. You don't need to change wallets or learn new tools.
• Permit2: A gasless approval standard that lets you authorize swaps without a separate approval transaction. One signature, one swap, zero extra gas.

mev redistribution

Most swaps on Ethereum generate mev. Arbitrage between your trade and other markets, sandwich opportunities from the price impact you create, and backrun profits from the state change you trigger — all of this value is typically captured by searchers and builders.

Fast Protocol's auction mechanism forces builders to compete for your order flow by offering the best execution price. The result: at least 90% of the mev your transaction generates flows back to you as an improved swap rate.

This isn't charity. It's auction dynamics. When multiple builders compete for the right to include your transaction, they bid up the value they're willing to return to you. The protocol enforces a 90% minimum, but competitive pressure often drives the actual redistribution higher.

Why it matters

Ethereum's base layer was designed for security and decentralization, not speed. That's the right tradeoff. But it means that simple actions like swapping tokens involve 12+ seconds of uncertainty and exposure to mev extraction.

Fast Protocol adds a commitment layer on top of Ethereum without changing anything about Ethereum itself. Your transactions still settle on L1. Your funds never leave mainnet. The additional speed and mev protection come from the mev-commit preconfirmation protocol — a coordination layer between users, builders, and validators that makes the existing system work better for everyone.