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fastrelay.sh
Integrating the relayA signed transaction flies a direct approach through FastRelay and touches down in slot N.SIGNED TXNSLOT N
A signed transaction flies a direct approach through FastRelay and touches down in slot N.

FastRelay — Client Integration Guide

Introduction

FastRelay is an ultra-low-latency Solana transaction relay designed for traders, market makers, and automated systems requiring sub-millisecond dispatch.

Your client submits a pre-signed Solana transaction to FastRelay, and it is immediately delivered using a highly optimized, leader-aware pipeline engineered for speed — with stake-weighted priority delivery for maximum transaction inclusion rates.

Broadcast Pipeline

Every transaction is broadcast simultaneously through 5 channels:

  1. Stake-Weighted QUIC (Primary) — Priority delivery across multiple global endpoints
  2. QUIC TPU — Direct to current + next 48 Solana leaders via QUIC
  3. UDP TPU — Fire-and-forget UDP to leaders
  4. RPC Fan-out — Parallel sendTransaction to multiple RPC endpoints
  5. ROC Relayers — Jito Block Engine and custom relayers

Submission Modes

The relay provides three submission modes:

A) QUIC (Recommended — 0.1ms possible)

Persistent, connection-oriented, extremely low overhead.

B) WebSocket (wss://) — persistent, browser-native

Open one socket per region, then stream transactions or atomic bundles for as long as you like. One TLS handshake at connect, none afterwards. Works from browsers and every modern language without a custom client.

C) Standard HTTPS

Simplest integration, but typically 15–25ms latency.

All three modes accept both single transactions and atomic Jito bundles — up to 5 transactions that land together or not at all, submitted straight to the Jito Block Engine.

The rest of this guide

PageWhat's on it
EndpointsQUIC, HTTPS and WebSocket addresses for all four regions
API KeysOptional keys, and the three ways to pass one
Rate Limits5 rps unstaked, rising to 200 with stake
Tip WalletsThe eight tip wallets and the minimum tip
Your Effective RateQuery the tip and limit that apply to a wallet
Transaction SupportLegacy and versioned transactions, size limits, ALT
Sending via QUICThe recommended path, with Rust and Python examples
Sending via HTTPSThe simplest path — a standard REST POST
Sending via WebSocketPersistent streams for transactions and bundles
Atomic BundlesJito bundles, both tip requirements, landing semantics
Responses & ErrorsResponse shapes and the full error-code reference
Performance & MonitoringKeep-alive, latency breakdown, co-location, ping

Support

For technical support or colocation inquiries: