FAQ

General Questions

What is Shield?

Shield is a specialized RPC service that allows Bitcoin transactions to be submitted directly to mining pools, bypassing the public mempool. This creates a private channel for transaction delivery that enhances privacy and eliminates MEV-related risks.

How does Shield differ from broadcasting transactions normally?

When broadcasting transactions normally through the Bitcoin P2P network, your transaction is first visible to all nodes in the network before reaching miners. This exposure creates opportunities for frontrunning, sandwich attacks, and other MEV extraction. Shield delivers transactions directly to mining pools without this public exposure.

Which Bitcoin networks does Shield support?

Currently, Shield only supports Bitcoin mainnet. Support for testnet may be added in future releases.

Is Shield open source?

No, Shield is a proprietary service offered by Rebar Labs.

Technical Questions

What mining pools accept Shield transactions?

Shield has direct integration with mining pools representing a significant portion of Bitcoin's hashrate. The /info endpoint provides hashrate estimates for different fee levels.

How do I know my transaction was successfully submitted?

When a transaction is successfully submitted, Shield returns the transaction ID. This indicates that the transaction has been accepted by Shield and will be relayed to mining pools. However, as with any Bitcoin transaction, confirmation depends on miners including it in a block.

What happens if my transaction isn't mined?

Transactions submitted through Shield remain in our private mempool for a limited time. If not mined within this period, they may be purged. We recommend resubmitting with a higher fee if confirmation is taking longer than expected.

Does using Shield guarantee my transaction will be mined?

No. While Shield provides direct access to mining pools, mining pools still prioritize transactions based on fee rates. Higher fee rates increase the likelihood and speed of confirmation, but there are no guarantees in Bitcoin mining.

Fee Questions

How do I determine the right fee rate?

The /info endpoint provides fee recommendations with corresponding estimated hashrate percentages. Choose a fee rate based on your confirmation urgency. Higher fee rates connect to more hashrate, increasing the chance of quick confirmation.

Can I adjust my fee after submission?

No. Once submitted, transactions cannot be modified. If you need faster confirmation, you would need to create a new transaction with a higher fee using Replace-By-Fee (RBF) techniques, if your wallet supports this. Note that not all mining pools support RBF at this time.

Why does Shield require a separate fee?

Shield fees compensate the participating mining pools. This fee structure incentivizes miners to accept private transactions directly rather than only mining from the public mempool.

Privacy and Security

Are my transactions private when using Shield?

Transactions sent through Shield bypass the public mempool, preventing exposure to the broader network before mining. Shield does not prevent transactions with a standard fee from being relayed by mining pools. However, once mined into a block, they become part of the public blockchain like any other transaction.

Does Shield store my transaction data?

Shield temporarily stores transaction data in its private mempool until the transaction is mined or expired. We do not permanently store transaction data beyond what's necessary for operational purposes.

Is my connection to Shield secure?

Yes, all API communications with Shield use HTTPS with TLS 1.2 or higher to ensure secure data transmission.