How FRB approaches chain-specific routing

Every chain behaves differently. Ethereum offers the deepest liquidity and most mature relay ecosystem, whereas BNB Chain rewards aggressive token hygiene, and Base focuses on tight fee control. This hub consolidates the playbooks our desks use so you can evaluate which venues deserve capital and how to bootstrap safely.

Start with the big idea: private bundles should be your default lane. Public PGAs are useful for canaries or parity checks, but they introduce noise and leak strategies. FRB’s refund guard, Ops Pulse telemetry, and Latency Test tool make it easier to adapt without improvising settings under pressure.

Private relays vs public PGAs

Private relays let you send sealed bundles directly to searcher-friendly builders. You get predictable inclusion probabilities, better refund behavior, and less competition. Public PGAs remain a fallback—think of them as an escape hatch when relays degrade or when you only need to test a hypothesis with tiny size.

• Define exactly when FRB is allowed to fall back to public (e.g., relay outage).
• Limit fallback size to ≤10% of the session cap and log each attempt.
• Review Ops Pulse charts weekly to see whether public attempts still add value.

Per-chain snapshots

Use the summaries below to decide where to deploy first, then dive into the individual guides for deeper routing, latency, and compliance notes.

Ethereum

Deepest liquidity, largest number of relays, and strictest scrutiny. Baseline with the Ethereum guide before cloning routes elsewhere. Focus on Flashbots integration, per-pair budgets, and comprehensive logging.

BNB Chain

High throughput with uneven router quality. Stick to audited allowlists, enforce liquidity minimums, and record every refund reason to stay ahead of exploit waves.

Polygon

Sensitive to endpoint jitter. Follow the Polygon guide for best practices on WSS rotation and gas multipliers when baseFee swings.

Base

Friendly fee profile with Coinbase sequencer nuances. The Base playbook covers how to stage routes in simulation, log Ops Pulse metrics, and scale after clean sessions.

Arbitrum

Fast rollup windows with occasional throttling. See Arbitrum MEV for latency windows, recommended routing, and how to measure inclusion deltas during sequencer bursts.

Optimism

Fee-aware chain that rewards patient scaling. Read the Optimism guide for canary promotion steps, refund governance, and documentation habits.