FastLane on Polygon (PFL) - Spam Reduction / MEV

Hi! My name is Alex (Thogard) and I am the CEO of FastLane Labs.

Hot on the heels of the Polygon Delhi hard-fork, the conversation swirls about reorg abatement and gas price fluctuations. Users and developers wait with bated breath to see the long-term results of the fork, and manifest high hopes for the future of the Network. Meanwhile, it can be frustrating to feel powerless to effect positive change on the Network outside of governance. In 2023, there’s a new way for Validators to make additional progress on the problems identified in PIP-5 and PIP-6!

PFL offers a way for Validators to influence the health and speed of the Network with minimal changes, and to get rewarded for doing so. Despite being an MEV-like protocol there is no customized software (or associated security risks), and while a patch to Sentries is required, this patch reduces the stress Sentries place on the Validator by substantially reducing the number of redundant transactions being forwarded. If there is large enough adoption for FastLane across the entire network, Polygon’s health will increase significantly!

Key Points

  • Validators earn MATIC from users competing for a specific position in the Block (MEV)
  • Since user bids are auctioned externally, the amount of “spam” transactions are greatly reduced
  • By reducing the volume of “spam” transactions, there will be a significant reduction in network stress (and, by proxy, reorgs) as a result
  • Additionally, a reduction in “spam” transactions will create an environment where gas prices become far more predictable for users

External Auctions & MEV

In a typical EVM setting, the user that “wins” a profitable trade is whoever’s transaction arrives first. However, due to a design choice in Geth–which Bor is based on–the “first” transaction to arrive ends up being chosen at random. This randomization encourages users (and bots) to spam duplicate transactions in hopes of increasing their odds of arriving first. FastLane’s external auction removes this randomization and replaces it with a structured auction system whereby users can pay Validators an additional Auction Bid to prioritize their transaction and arrive first. Therefore, by placing an Auction Bid outside of the typical Max Gas and Priority fees, the user can prioritize their transaction without inflating existing network gas rates for common users. There’s no more incentive for bots to spam hundreds of transactions just to increase their odds of one of the transactions winning the lottery and arriving first - the winner is now chosen by who bids the highest, not who spams the most.

Is it safe?

A major concern when running any third-party patch will of course be safety, particularly in crypto. As mentioned above (but worth re-iterating here), FastLane requires absolutely no custom software to be run on the Validator, and only requires a small patch to the Sentry node. As a result, the Validator continues to run the official Bor code base which nullifies a chief insecurity vector. We’ve worked hard to create a protocol that doesn’t create any dev ops dependencies and we encourage all validators to continue to follow and implement all updates from the Polygon team. Should all of the FastLane-run nodes be taken offline, the Validator node and all patched Sentries will continue to function normally; there is no centralization risk. Additionally the design and structure of FastLane ensures that neither Sandwich Attacks or Front-Running are possible. Of course, this short-form look won’t go into deep detail, but there is much more information available in the FastLane whitepaper.

Getting Started

So you want to get started in boosting your Validator output and begin safeguarding the Polygon user experience; taking the plunge into implementation could not be more simple!

  1. Join FastLane’s Discord to request Approval for your Validator
  2. Connect your Validator Node to a FastLane Sentry
  3. Patch your existing Sentry Node(s) with the FastLane Patch
  4. Visit the Validator Vault dApp and accumulate!

It is the goal of the FastLane team to get as many Validators as possible on-board this year; Polygon is poised to become an even more powerful juggernaut in the world of Web3, and having a fast, stable, and safe Network rests on the shoulders of the infrastructure providers (IE Validators) supporting it. FastLane affords the opportunity for the Network to always put its best proverbial foot forward, and your adoption moves us closer to that goal.

Currently, 20.5% of blocks on Polygon are produced by Validators participating in the FastLane protocol. This is a very important conversation to have about MEV, spam, user experience and the health of the network. I’d love to answer any questions and address any concerns you may have.


Great info, Alex. We’re excited that the fork went extremely smoothly, and look forward to the positive changes it will bring to the network. In the meantime, however, we’re also excited for our more proactive approach by working with FastLane.

For the past few months, we’ve worked closely together to ensure any changes would not have adverse effects on the sentries or especially the validator. During this time, we have not seen any additional stress on our servers and no negative impact on the blockchain, such as an increase in reorgs. Between our own monitoring and FastLane’s logging, we’ve also gained a greater understanding on maintaining our uptime.

We’re also excited to see how searchers utilize FastLane. By not having to be concerned about network transaction propagation or latency, searchers might find new arb possibilities. We are eager to see how the bidding plays out as well.


It is great to finally see a solution that - hopefully - will solve for all the MEV bad externalities on Polygon. Do you know how much MEV there is on Polygon?
Whether you are a searcher or a validator it should be of great interest to you. We are doing some research on quantifying it, and we will post the results here on the Flashbots Forum. In the meantime, go and have a read there and give us your estimation in the poll.

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