What Is ACE? (Application-Controlled Execution)
Application-Controlled Execution (ACE) is Solana’s plan to give applications their own say in how their transactions get ordered—rather than leaving transaction ordering exclusively up to validators and block builders. As the roadmap notes, the idea is to give smart contracts millisecond-level command over their own transaction sequencing. ACE anchors the long-range end of the Solana Foundation–backed Internet Capital Markets roadmap, released in July 2025 by a coalition of the Solana Foundation, Anza, Jito Labs, DoubleZero, Drift, and Multicoin Capital. Delivery is targeted for 2027 and beyond.
Picture a shopping mall. Today’s blockchain is like a mall where a single security guard at the entrance chooses the order that shoppers get to enter each store. ACE hands each store control of its own door: bookstore customers go on a first-come-first-served basis; auction house buyers get time-based bidding rounds; the jeweler screens the entry and then accepts orders. All the while, the mall is still ensuring people cannot fake their purchase.
Why Order Matters—And Who Gets to Decide
The Solana team identified market microstructure—the detailed rules about how orders meet and trade in the markets—as the network’s most pressing unsolved issue. On any single-leader blockchain, the leader of the block gets to choose the order of all transactions in the block, and ordering is where MEV extraction (the practice of reordering transactions, sandwiching and frontrunning users’ transactions to make a profit) gets its power.
It’s not just nice to have order, in finance, it is essential. A price update before or after a liquidation makes all the difference for who’s paying and who’s being paid for. The way traditional exchanges solve this problem is by specifying very clearly the matching rules: cancel orders before a new one; price and time priority down to the microsecond. With on-chain protocols, these guarantees simply haven’t existed because ordering is the job of the validator, not the venue. With ACE, that order of operations can be set by the application itself. For example, the Drift derivatives exchange protocol could enforce cancel-priority, so market makers could offer tighter spreads; or the Pyth price oracle could ensure its price update always arrives before the trades that require them.
Roadmap to Delivery: Three-Phase Rollout
The roadmap isn’t waiting for everything to be perfect before starting. In the short term, you have Jito’s BAM Block Assembly Marketplace, which has already been live on mainnet since September 2025 and offers most of the power of full ACE. It lets developers plug in custom logic for order sequencing for their application and run the custom logic inside Trusted Execution Environments (TEE) to make sure they follow the rules, with verifiable, cryptographic proofs of those assurances. Drift, Pyth, and DFlow are among the first design partners building custom sequencing plugins.
The medium term is for making applications fast enough to have real application control; that’s when Alpenglow reduces time to finality from 12.8 seconds to 150ms on mainnet by the end of 2026 and DoubleZero runs a dedicated fiber network that has already been taken up by 59% of stake weight. The final step will come with the multiple concurrent leaders that will be running the most liquid markets by the end of 2027.
On Ethereum, the ecosystem is dealing with a similar disease, only the cure looks a bit different. Proposer-builder separation, order-flow auctions, and encrypted mempools are all attempts to mitigate MEV issues at the protocol/infrastructure layer. ACE is a more radical proposal: let the application itself control ordering. Criticisms are fair in pointing out this is the path already taken by the centralized-sequencer chains like Hyperliquid-style venues. And, of course, BAM has to go the hardware-trust/TEE route through the Jito stack. Solana, in the end, intends to offer this same capability on its permissionless base settlement layer while maintaining fees at ~$0.00025 per transaction.
Why ACE Matters
ACE is a statement by the Solana Foundation that the endgame is not just about lower fees for swaps, but about building markets that are structured with guarantees of order and timing on-chain. For end users, application-controlled ordering leads to tighter spreads and no hidden sandwich taxes. For the developers building on Solana, ordering is a feature you can design, not something you just get stuck with. For the competition between chains, ACE defines the next phase of the race: Ethereum will go for a more neutral, infrastructure-only approach and keep MEV at the edges, while Solana is betting on the idea that letting applications control execution of their own code is what it takes to bring the whole capital markets online.
