Private RPCs and MEV Protection: Do They Save Money?

By Chanuka Geekiyanage Oct 26, 2026

A private RPC sends your transaction straight to block builders instead of the public mempool, the open waiting area where bots can see pending trades and sandwich them. Setting one up on Ethereum is free, but the savings are uneven. They come mostly from avoiding a bad fill, not from the rebates that get the marketing. This article shows where the money comes from, how Flashbots Protect, MEV Blocker, Merkle, and Blink compare, and when a private RPC does almost nothing for you.

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Where the Savings Actually Come From

Private RPCs can save you money in four ways. Only the first is large, and only for some trades.

Avoided sandwich losses: A bot buys before your swap and sells after it, so you get fewer tokens. This is the biggest saving, but it matters mainly in thin pools or with loose slippage.
Revert protection: Transactions sent to Flashbots Protect are not executed if they revert, so users do not pay for failed transactions. MEV Blocker offers the same through its /noreverts endpoint.
MEV rebates: When a searcher profits by trading right after your swap (a backrun), part of that profit comes back to you. These payouts are small.
Gas refunds: Flashbots Protect refunds overpaid gas when BuilderNet lands the block.

How Much Sandwich Attacks Really Cost

EigenPhi data analyzed by Cointelegraph Research covers more than 95,000 sandwich attacks from November 2024 to October 2025, with annual trader losses of about $60 million. Monthly extraction fell from nearly $10 million in late 2024 to about $2.5 million by October 2025, even as DEX volume rose. That is real money, but small next to DEX volume in the tens of billions of dollars a month.

My read is that most swappers in liquid pairs are rarely hit. The pain is concentrated in low-liquidity tokens and trades with wide slippage tolerance.

A May 2025 case shows the shape of the problem. A trader swapping 0.83 ETH for RATO on Uniswap V2 received almost 10 million fewer tokens than they would have without the front-run. That is roughly 6% less. The attacker’s net profit was only about $4.32 after gas and fees, because most of the gross went to the builder.

The victim’s loss and the attacker’s profit are very different numbers. Builders collect much of the difference through gas.

Image source: Cointelegraph Research

Notice that extraction fell while trading volume rose. That suggests defenses and slimmer margins are working, so your expected savings from a private RPC today are lower than older articles imply.

What Rebates Pay Back, and Why It Is Small

Flashbots reports that Protect has served 2.1 million Ethereum accounts, covered $43 billion in DEX volume, and paid out 313 ETH in MEV refunds. Spread across all accounts, that is about 0.00015 ETH each. The post is from 2025, so check the live dashboard for current totals.

Compare the top single refunds on the leaderboard with a typical user’s refund. A few large trades capture most of the value.

Flashbots also added gas refunds in 2025. At the time, the feature was live in about 2% of blocks and had earned users over 50 ETH. Refunds only apply when BuilderNet wins the block, which is why Flashbots lets you share transactions with other builders for speed.

Rebates also depend on your trade creating a backrun. Even less liquid pairs do not generate backruns every time. Treat rebates as a bonus, not a reason to switch.

Flashbots Protect vs MEV Blocker vs Merkle and Blink

For Ethereum, three providers matter. If you want a wider side-by-side with more endpoints, this private RPC comparison for DeFi traders goes further.

Flashbots Protect

Flashbots has the longest track record. By default, it shares only the hash and default log hints with MEV-Share searchers and sends 90% of MEV refunds to the tx. origin, with the rest going to the validator. Fast mode shares your transaction with all registered builders for quicker inclusion, but you must trust each builder not to front-run or leak it.

You can tune privacy with hints. Setting only the hash hint gives full privacy but will likely cut your refund.

MEV Blocker

MEV Blocker is built by CoW Protocol, Agnostic Relay, and Beaver Build. Users receive 90% of the profit a backrun creates, and the rebate is paid to the sending address in the same block. It is permissionless, with no sign-up.

It offers several endpoints. These include fast, noreverts, fullprivacy (maximum privacy, no rebates), maxbackruns, and nochecks, which skips simulation. Pick the endpoint that matches your goal, because they trade rebates, privacy, and safety checks against each other.

Merkle and Blink

Both launched in late 2023. An API key is required to receive MEV refunds; otherwise, both providers keep the full value extracted. That makes them a poor default for individual users.

Option	Chain	Refund model	Main weakness	Best for
Flashbots Protect	Ethereum	90% of MEV-Share refund to sender by default, plus gas refunds in BuilderNet blocks	Smaller rebates than MEV Blocker in a 2025 benchmark	Users who value track record and free reverts
MEV Blocker	Ethereum	90% of searcher bids to sender, 10% to validators	Benchmark favoring it is self-published	Swappers who want rebates and fast inclusion
Merkle / Blink	Ethereum	Refunds need an API key	Lowest rebates in the benchmark, Merkle lowest success rate	Teams with an API arrangement
Jito DontFront	Solana	None	Docs say it is not guaranteed	Solana users and developers

A 2025 benchmark compared the four Ethereum RPCs by sending identical transactions through each. Average inclusion delay was 1.34 blocks for MEV Blocker, 1.49 for Flashbots, 1.56 for Blink, and 1.86 for Merkle. Average rebates were 0.0035 ETH, 0.0016 ETH, 0.0000 ETH, and 0.0009 ETH in the same order.

Read this with caution. The study is published in MEV Blocker’s own documentation, and it used 273 transactions. Flashbots has also added gas refunds since. I treat it as directional, not final.

Notice which endpoints say no rebates and which skip simulation. Those labels tell you what you give up for each setting.

Do You Need This on L2s or Solana?

On most Ethereum L2s, the case is weaker. On Base and Arbitrum, transactions are not broadcast to a public mempool, so the advice is to keep slippage limits and deadlines in your contracts. A 2026 study found sandwiching is rare, unprofitable, and largely absent on rollups with private mempools.

Solana is different. A May 2025 analysis estimated sandwich bots extracted between $370 million and $500 million from Solana users over 16 months. Jito’s DontFront feature helps, but Jito says it may reduce sandwiching without guaranteeing it, and the Solana docs call limiting slippage the single most effective defense.

Risks and Tradeoffs

A private RPC is not free of cost, even when it is free to use.

Builder trust: You are trusting the builders and the RPC operator not to front-run or leak your transaction.
Uneven inclusion: One Flashbots transaction in the benchmark took 7 blocks, while the next slowest took 4. Expect occasional delays.
Less rebate for more privacy: Maximum-privacy settings reduce or remove rebates.
Stuck transactions: Cancelling can be harder. MEV Blocker’s soft cancellations work only on the noreverts and fullprivacy endpoints.
False confidence: Private routing cannot guarantee favorable execution or eliminate every form of MEV.
Fake RPC URLs: A malicious endpoint sees every transaction you send. Copy URLs only from official documentation.

Decision Framework

Match the tool to the trade, not to the hype.

Situation	Recommended option	Why
Large swap in a liquid Ethereum pair	MEV Blocker default endpoint	Backruns are likely, so the rebate has a chance to matter
Thin-liquidity token on Ethereum	MEV Blocker full privacy or Flashbots hash-only, plus tight slippage	Sandwich risk is highest, so privacy beats rebates
Interaction that might revert	MEV Blocker no reverts or Flashbots Protect	Failed transactions are not executed, so no gas is lost
Small swap in a deep pool	Optional	My estimate is cents of savings, so setup effort may not pay off
Base or Arbitrum	Default RPC with tight slippage	No public mempool, sandwiching rare
Solana swap	App that uses Jito protection, plus low slippage	DontFront helps but is not guaranteed

The cheaper lever is almost always slippage and pool choice. Intent-based swaps, which let solvers compete to fill your order, are another option, and this guide to MEV protection tools for sandwich attacks on DEXs covers them.

My Take

If you trade on Ethereum mainnet, set MEV Blocker as your default RPC. It led the 2025 benchmark on speed and rebates; it is free, and the endpoint options are clear. Because that benchmark is self-published, Flashbots Protect is an equally reasonable pick if you value its longer history.

I would skip Merkle and Blink unless you already have an API key arrangement. Individual users get the weakest deal there.

Do not switch for the rebates. Switch to avoid a bad fill on a thin token and to stop paying for failed transactions. Before using any RPC, copy the URL from official docs, send a small test transaction, and set slippage as low as the trade allows.

If you mostly swap small amounts in deep pools, or you trade on Base or Arbitrum, the benefit is small. Spend that effort on slippage settings instead.

Conclusion

Private RPCs do save money, but mainly by protecting you from sandwiches and failed transactions. Rebates are real and small: Flashbots’ 313 ETH across 2.1 million accounts averages out to a fraction of a cent for most people. The savings are largest for big trades and thin tokens.

The trade-offs are builder trust, occasional slower inclusion, and a false sense of safety. For Ethereum, MEV Blocker is the default I would pick, with Flashbots Protect as the alternative. The practical next step is to add the official endpoint, test it with a small transaction, and keep your slippage tight.

FAQs

1. Do private RPCs cost anything to use?

Flashbots Protect and MEV Blocker are free to use on Ethereum. Merkle and Blink require an API key to receive refunds, and without one, they keep the extracted value.

2. Can I still get sandwiched with a private RPC?

Yes, because private routing cannot guarantee favorable execution or remove every form of MEV. Loose slippage and trusting a builder who misbehaves are the main remaining risks.

3. Which is better for beginners, Flashbots Protect or MEV Blocker?

Either works, and both are added to a wallet as a custom RPC. MEV Blocker’s default endpoint is simpler to start with, while Flashbots Protect has the longer track record.

4. Do I need a private RPC on Base or Arbitrum?

Usually not, because these chains do not broadcast transactions to a public mempool. Tight slippage and sensible pool choice matter more there.

5. Will a private RPC make my transaction slower?

Sometimes, though, average delays in the 2025 benchmark were about 1.3 to 1.9 blocks. Occasional outliers happen, so avoid private routing alone for time-critical trades.

References

Flashbots Docs, MEV Refunds: https://docs.flashbots.net/flashbots-protect/mev-share

Flashbots Docs, Settings Guide: https://docs.flashbots.net/flashbots-protect/settings-guide

Flashbots Docs, Gas Fee Refunds: https://docs.flashbots.net/flashbots-protect/gas-fee-refunds

Flashbots Docs, Quick Start: https://docs.flashbots.net/flashbots-protect/quick-start

Flashbots Writings, 2 Million Protect Users: https://writings.flashbots.net/2m-protect-users

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About the Author: Chanuka Geekiyanage

Chanuka is a content writer, editor and contributor at Panaprium, specializing in long-form editorial articles. He conducts in-depth research and produces well-structured, carefully edited content with a strong focus on clarity, SEO best practices, and consistent formatting. His work spans lifestyle, fashion, wellness, and technical topics, and all articles are reviewed and refined to meet Panaprium’s editorial standards.

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