proxyd

proxyd is an important RPC request router and proxy used within the OP Stack infrastructure. It enables operators to efficiently route and manage RPC requests across multiple backend services, ensuring performance, fault tolerance, and security.

Key features

RPC method whitelisting
Backend request routing
Automatic retries for failed backend requests
Consensus tracking (latest, safe, and finalized blocks)
Request/response rewriting to enforce consensus
Load balancing across backend services
Caching of immutable responses
Metrics for request latency, error rates, and backend health

How it works

To start using proxyd, follow these steps:

Build the binary:

Run the following command to build the proxyd binary:
```
make proxyd
```
This will build the proxyd binary. No additional dependencies are required.

Configure `proxyd`:

Create a configuration file to define your proxy backends and routing rules.
Refer to example.config.toml (opens in a new tab) for a full list of options with commentary.

Start the service:

Once the configuration file is ready, start the proxyd service using the following command:

proxyd <path-to-config.toml>

Consensus awareness

Version 4.0.0 and later include consensus awareness to minimize chain reorganizations.

Set consensus_aware to true in the configuration to enable:

Polling backends for consensus data (latest block, safe block, peer count, etc.).
Resolving consensus groups based on healthiest backends
Enforcing consensus state across client requests

Caching and metrics

Cacheable methods

Certain immutable methods, such as eth_chainId and eth_getBlockByHash, can be cached using Redis to optimize performance.

Metrics

Extensive metrics are available to monitor request latency, error rates, backend health, and more. These can be configured via metrics.port and metrics.host in the configuration file.

Next steps

Read about the OP Stack chain architecture.
Find out how you can support snap sync. on your chain.
Find out how you can utilize blob space to reduce the transaction fee cost on your chain.

proxyd Intro to OP Stack hacks