Networks, Public RPC Endpoints, & APIs


Developer Tip

We recommend using Alchemy (opens new window) for its scalablity, reliability, and data accuracy.

Note

Some API calls, such as the those in the personal namespace (opens new window) make no sense in a shared environment. Such RPCs are either totally unsupported, or will return nonsensical values.

# Optimism (mainnet)

Parameter Value
Network Name Optimism
Description Mainnet
Chain ID 10
Explorer https://optimistic.etherscan.io (opens new window)
HTTP Endpoint1 We recommend Alchemy (opens new window). Optimism also provides this endpoint: https://mainnet.optimism.io. But it is not for production systems and is rate limited.
WebSocket Endpoint2 wss://ws-mainnet.optimism.io
L1 Contract Addresses link (opens new window)
L2 Contract Addresses link (opens new window)
chainid.link https://chainid.link/?network=optimism (opens new window)

(1) Some API calls, such as those in the personal namespace (opens new window) make no sense in a shared environment. Such RPCs are either not supported, or will return nonsensical values.

(2) The WebSocket endpoint is only supported for the two operations that cannot be provided on an HTTP endpoint: eth_subscribe and eth_unsubscribe. If you need a general purpose WebSocket endpoint, get one from a service provider._

# API Options:

  1. Get free access to Optimism through Alchemy (opens new window)

  2. For small scale tests, you can use our public API:

You can run a large application for free using Alchemy (opens new window). We’ve done extensive diligence and Alchemy is our recommendation due to reliability, scalability, and data correctness. They're the default API provider and developer platform for top projects like OpenSea and Facebook.

# Optimism Goerli

Purpose

This is our new test network.

Parameter Value
Network Name Optimism Goerli
Description Testnet (public)
Chain ID 420
Explorer https://goerli-optimism.etherscan.io/ (opens new window)
HTTP Endpoint https://goerli.optimism.io
WebSocket Endpoint wss://ws-goerli.optimism.io
L1 Contract Addresses link (opens new window)
L2 Contract Addresses link (opens new window)
chainid.link https://chainid.link/?network=optimism-goerli (opens new window)

# API Options

  1. Get free access to Optimism through Alchemy (opens new window)

  2. For small scale tests, you can use our public API:

You can run a large application for free using Alchemy (opens new window). We’ve done extensive diligence and Alchemy is our recommendation due to reliability, scalability, and data correctness. They're the default API provider and developer platform for top projects like OpenSea and Facebook.

# Test ETH

The Optimism Faucet (opens new window) now provides Optimism Goerli ETH. Alternatively, if you already have Goerli ETH, you can bridge it (opens new window).

# Optimism Kovan (old testnet)

Deprecation notice

We are transitioning our test network to Goerli. Optimism Kovan end of life is October 5th, 2022. Be sure to migrate from Kovan to Goerli (opens new window) well before then.

Parameter Value
Network Name Optimism Kovan
Description Testnet (public)
Chain ID 69
Explorer https://kovan-optimistic.etherscan.io (opens new window)
HTTP Endpoint https://kovan.optimism.io If you are going to be sending a lot of requests, please set up a free account with Alchemy
WebSocket Endpoint1 wss://ws-kovan.optimism.io If you are going to be sending a lot of requests, please set up a free account with Alchemy
L1 Contract Addresses link (opens new window)
L2 Contract Addresses link (opens new window)
chainid.link https://chainid.link/?network=optimism-kovan (opens new window)

(1) The WebSocket endpoint is only supported for the two operations that cannot be provided on an HTTP endpoint: eth_subscribe and eth_unsubscribe. If you need a general purpose WebSocket endpoint, get one from a service provider.