> ## Documentation Index
> Fetch the complete documentation index at: https://base-a060aa97-fix-dead-service-links.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Flashblocks Architecture

> Understand the sequencer architecture and infrastructure components that power Flashblocks on Base.

## Before Flashblocks

Base operates a high-availability sequencer system with five sequencer instances:

| Component          | Role                                                                 |
| ------------------ | -------------------------------------------------------------------- |
| **base-consensus** | Consensus layer (CL) — replaced op-node after Azul                   |
| **base-reth-node** | Execution layer (EL) — replaced op-geth after Azul                   |
| **op-conductor**   | High availability controller with Raft consensus for leader election |

One sequencer instance acts as the **leader**, responsible for building blocks and propagating them via P2P. The remaining four act as **followers** that sync the chain. Leadership transfers if the current leader stops producing blocks.

## With Flashblocks

Flashblocks introduce several new infrastructure components:

| Component                                | Purpose                                  | What It Unlocks                                                                                                                                     |
| ---------------------------------------- | ---------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------- |
| **rollup-boost**                         | CL↔EL Engine API proxy                   | Enables sharing Flashblocks with the EL without modifying the CL. Provides a stable seam for future block-building evolutions (multi-builder, etc.) |
| **base-builder**                         | Out-of-protocol builder at 200ms cadence | Produces the sub-second Flashblocks, decoupled from the EL. Enables pluggable builder mechanisms                                                    |
| **websocket-proxy**                      | Flashblocks stream fan-out               | Broadcast layer so many consumers can read the stream without overwhelming the builder                                                              |
| **[base](https://github.com/base/base)** | RPC surface exposing preconfirmations    | Converts streamed Flashblocks into familiar RPCs so apps and wallets can consume preconfirmation state                                              |

[rollup-boost](https://github.com/flashbots/rollup-boost) is built and maintained by Flashbots, while Base maintains [base-builder](https://github.com/base/base/tree/main/crates/builder), the websocket-proxy, and the [base](https://github.com/base/base) components.

***

## Further Reading

* [Flashblocks Overview](/base-chain/flashblocks/overview) — Key concepts and transaction lifecycle
* [Enable Flashblocks](/base-chain/node-operators/run-a-base-node#enable-flashblocks) — Run your own Flashblocks-aware RPC node
* [API Reference](/base-chain/api-reference/flashblocks-api/flashblocks-api-overview) — RPC methods, WebSocket subscriptions, and infrastructure stream schema
* [Flashblocks Deep Dive](https://blog.base.dev/flashblocks-deep-dive) — Engineering blog post with implementation details