Announcing Rebar Shield: MEV-Protected Transactions on Bitcoin

Today, we’re excited to announce Rebar Labs’ first product: Rebar Shield. Rebar Shield allows Bitcoin users to submit transactions via RPC through a private mempool, bypassing Bitcoin’s public mempool and protecting users from emerging Bitcoin MEV strategies.

As programmability grows on Bitcoin — with existing metaprotocols Ordinals, Runes, and BRC-20s, as well as new paradigms like OP_NET — it’s time to think about Maximum Extractable Value, or MEV: The value that sophisticated players can extract by reordering, inserting, or censoring transactions within blocks. Whereas MEV is a well-known phenomenon largely on Ethereum, we expect to see it occur on Bitcoin as Bitcoin's onchain activity grows more complex with new metaprotocols and DeFi activities.

Our mission is to give Bitcoin's ecosystem the tools to address MEV, ensuring fair and transparent markets for users and new opportunities for miners — and to this effort, we’re happy to announce our first product.

Rebar Shield protects Bitcoin users from emerging MEV (Maximum Extractable Value) strategies. It provides an alternative to the public mempool, allowing users to submit their transactions directly to miners through a private mempool.

This approach ensures that transaction details remain confidential until they're included in a block, significantly reducing the risk of MEV-related manipulations.

For Bitcoin users:

• Reduced MEV Exposure: By bypassing the public mempool, your transactions are hidden from MEV strategies — like frontrunning and sniping — until they're mined.
• Better Privacy: Transaction details remain private until inclusion in a block.
• Easy Integration: Users and wallet providers can integrate Rebar Shield without changing their transaction submission process beyond switching RPCs.

For Mining Pools and Miners:

• New Revenue Streams: As block rewards diminish, Rebar Shield provides opportunities to capture MEV, helping to subsidize mining operations.
• Simple Integration: The Rebar Client is designed to work alongside existing Bitcoin Core nodes.

Rebar Shield consists of two main components:

• Rebar Shield Server: A JSON-RPC server with an interface similar to Bitcoin Core's JSON-RPC.
• Rebar Client: Software run by mining pools alongside their Bitcoin Core node.

Users submit their transactions via Rebar's RPC endpoint, using the same methods (sendrawtransaction and submitpackage) and data format they would use with a typical Bitcoin RPC. The Rebar Shield Server then filters these requests to ensure only the supported methods are being used. Valid transactions are then forwarded to Rebar Clients run by participating mining pools.

Mining pools process these transactions without rebroadcasting them to the public mempool, maintaining privacy until the transaction is included in a block.

This approach provides robust MEV protection by keeping transaction details private throughout the entire process, from submission to inclusion in a block.

Are you a wallet provider interested in integrating Rebar Shield, or a mining pool looking to participate? Reach out to us!

Rebar Shield will go live once we have integrated with a sufficient percentage of Bitcoin mining hash rate. We are in advanced discussions with all major mining pools, and we are allowing time for them to fully audit our code. Additionally, working with major Bitcoin wallet providers to give users the option to use Rebar Shield to protect their transactions.

As Bitcoin's ecosystem continues to evolve with new token standards, L2s, and sophisticated on-chain activity, the need for MEV protection becomes increasingly critical. Rebar Labs is at the forefront of addressing these challenges, ensuring that Bitcoin remains true to its core principles of decentralization, security, and fairness. Stay tuned for more updates as we continue to develop and expand our suite of MEV-aware products and infrastructure for Bitcoin. Together, we're building a stronger, fairer, and more resilient Bitcoin network for all. Follow us on X at @RebarLabs for the latest updates and to join the conversation about MEV on Bitcoin, and get in touch with us here!