Best MEV Relays by Chain (2026 Direct Execution Guide)

Answer first — MEV relay landscape in 2026 is fundamentally per-chain. Ethereum mainnet runs on a multi-builder fan-out model: serious searchers submit eth_sendBundle simultaneously to Flashbots, Titan, beaverbuild, and rsync-builder, with bloXroute as a paid commercial option. Solana is dominated by Jito Block Engine — bundles tip Jito tip accounts and are routed to participating validators; this is the only reliable way to get atomic inclusion on Solana. BNB Chain has Puissant (BSC-aligned validator path) and bloXroute BSC for the lowest-latency mempool subscription. Polygon has FastLane Atlas, a PBS-style auction running on the validator set with partial coverage; pair with public-mempool fallback. Optimism / Base / Arbitrum have no Flashbots-style bundle relays — atomicity comes from packing into a single executor-contract call. Match the relay to the chain; do not run "Ethereum-style" relay assumptions on chains that don't support them.

Mastery path

• What is MEV?
• Best Ethereum private RPCs
• Flashbots bundles explained
• Best MEV relays by chain (current)
• Jito bundles explained

Ethereum mainnet: multi-builder fan-out

Single-relay submission is a 30–60% block-share blind spot in 2026. The modern default is fan-out:

Fan-out same bundle to all four base relays simultaneously; first inclusion wins. Track per-relay inclusion rate and re-weight your fan-out toward consistent winners. The FRB Agent does this automatically.

MEV-Share is a separate hint protocol (not a builder); use it when you want OFA refund flow, but it doesn't replace eth_sendBundle to builders.

Solana: Jito Block Engine

Solana doesn't have a public mempool; transactions are forwarded directly to validators. Jito Labs runs a block engine that lets searchers submit atomic bundles to Jito-aware validators:

• Submission: bundle of (your tx + a Jito tip tx going to one of Jito's tip accounts).
• Tip dynamics: Jito sorts bundles by tip per compute unit. Static tip values lose; adaptive tipping calibrated against current slot leader's recent winning-tip distribution wins.
• Coverage: Jito-aware validators currently process the majority of stake on the Jito-MEV path. Non-Jito slot leaders ignore your bundle entirely — your tip falls into a different submission path.
• Failure mode: wrong slot leader (not Jito-aware), tip too low to clear, bundle malformed.

For Solana strategies (Pump.fun sniping, Raydium backruns, Jupiter-routed arbitrage) Jito is the canonical relay. There's no real alternative for atomic execution; non-Jito sends are first-confirmation roulette.

BNB Chain: Puissant + bloXroute

BSC has a real public mempool but no Flashbots-equivalent in the original sense. The relay landscape:

• Puissant — BSC-aligned validator path with direct relay access. Effective during normal hours; coverage depends on which BSC validators are integrated.
• bloXroute BSC — paid commercial relay with high-quality global infrastructure. The lowest-latency mempool subscription available for serious BSC operators.

Operating BSC strategies typically dual-routes bundles to both Puissant and bloXroute (where economics justify the bloXroute fee) to maximise inclusion across the validator set. The validators historically had an informal anti-MEV understanding that's been weakening; assume the validator set will sort by economics, not by neutrality.

Polygon: FastLane Atlas

Polygon's Heimdall + Bor architecture didn't have a Flashbots equivalent until FastLane Labs built FastLane Atlas, a PBS-style auction running on the Polygon validator set:

• Submission: atomic bundle through FastLane endpoints.
• Coverage: participating validators only. Non-participating slot leaders can't include your bundle.
• Pair with fallback: public-mempool fallback (with strict caps) for slots where the proposer isn't FastLane-aware.

For serious Polygon MEV in 2026, FastLane is the right tool when economics permit. For lower-volume operators, public-mempool with very strict slippage and gas caps still works — Polygon doesn't have the contestation level of mainnet.

Optimism, Base, Arbitrum: no bundle relay

These chains do not have Flashbots-style bundle relays. The closest substitutes:

• Single-tx atomicity through an executor contract. Pack your route into one transaction that calls a contract; the contract reverts on partial fill. The whole thing either lands or doesn't.
• Private RPC endpoints that don't rebroadcast your tx to the public peer-to-peer layer until inclusion. Most commercial RPCs sell this as a paid feature.
• Direct sequencer submission (allowlist) for very latency-sensitive flows on Arbitrum. Limited availability.
• Timeboost on Arbitrum — auction-priced express lane for sub-block priority.

The mistake to avoid: assuming "private bundle" semantics from Ethereum work the same way on these chains. They don't, and configuring your bot as if they do is a slow gas leak.

Choosing the right configuration

The FRB Agent ships with chain-appropriate relay configurations enabled per chain by default.

References

• Flashbots eth_sendBundle reference
• Jito Block Engine docs
• FastLane Atlas
• bloXroute BDN