Network
Launch Date
Consensus
Note
Sepolia
Oct 2021
PoW
Like-for-like representation of Ethereum
Görli
Jan 2019
PoA
Proof-of-Authority
Kiln
Mar 2022
PoS
Post-Merge (for ETH2), shadow fork of the mainnet
Kintsugi
Dec 2021
PoS
DEPRECATED, use Kiln; post-Merge (for ETH2)
Ropsten
Nov 2016
PoW
DEPRECATED, use Sepolia; the Merge to happen on Jun 8, 2022
Rinkeby
Apr 2017
PoA
DEPRECATED, use Görli and Görli Faucet
Kovan
Mar 2017
PoA
DEPRECATED, use Sepolia or Görli
List of active and deprecated Ethereum testnets, including Kintsugi.
Features
Optimistic rollup 
ZK-rollup 
Proof
Uses fraud proofs to prove transaction validity. 
Uses validity (zero-knowledge) proofs to prove transaction validity. 
Capital efficiency
Requires waiting through a 1-week delay (dispute period) before withdrawing funds. 
Users can withdraw funds immediately because validity proofs provide incontrovertible evidence of the authenticity of off-chain transactions. 
Data compression
Publishes full transaction data as calldata to Ethereum Mainnet, which increases rollup costs. 
Doesn't need to publish transaction data on Ethereum because ZK-SNARKs and ZK-STARKs already guarantee the accuracy of the rollup state. 
EVM compatibility
Uses a simulation of the Ethereum Virtual Machine (EVM), which allows it to run arbitrary logic and support smart contracts. 
Doesn't widely support EVM computation, although a few EVM-compatible ZK-rollups have appeared. 
Rollup costs
Reduces costs since it publishes minimal data on Ethereum and doesn't have to post proofs for transactions, except in special circumstances. 
Faces higher overhead from costs involved in generating and verifying proofs for every transaction block. ZK proofs require specialized, expensive hardware to create and have high on-chain verification costs. 
Trust assumptions
Doesn't require a trusted setup. 
Requires a trusted setup to work. 
Liveness requirements
Verifiers are needed to keep tabs on the actual rollup state and the one referenced in the state root to detect fraud. 
Users don't need someone to watch the L2 chain to detect fraud. 
Security properties 
Relies on cryptoeconomic incentives to assure users of rollup security. 
Relies on cryptographic guarantees for security. 
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Testnets
OPTIMISM GOERLI OVERVIEW

How to Migrate from Kovan to Goerli on Optimism

Migrating dApps and Bridging Goerli ETH to Optimism
Last Updated:

The Optimism team recently announced the migration from Kovan to Goerli for their testnet. This article will explain why web3 developers building on Optimism should migrate their dApps to Goerli, and how to migrate with Alchemy, a developer platform that supports Optimism applications.

Why is Optimism migrating from Kovan to the Goerli testnet?

Kovan is a Proof-of-Authority (PoA) test network, and it has been deprecated for over a year. As of this announcement, there are only two remaining validators left supporting the Kovan testnet. 

To keep parity with the Ethereum network throughout The Merge roadmap, Optimism applications should migrate to Goerli, another Proof-of-Authority testnet that will be maintained after The Merge is complete later this year.

Other Ethereum testnets have already been deprecated (like Ropsten), will be deprecated later this year like the Rinkeby test network, the Kiln merge testnet, and the Prater testnet

For more information on Ethereum’s testnet deprecation and merge timeline, refer to the official Ethereum blog.

When will Optimism and Alchemy end support for Kovan?

Optimism is aiming for all projects to be completely migrated to Goerli by August 15th, 2022, and Alchemy will end support for the Kovan testnet on October 5th, 2022

As we approach the end of support for Kovan, Alchemy will inform current users through in-app alerts, email notifications, and direct messages to Enterprise customers about upcoming deadlines.

How will the migration from Kovan to Goerli be rolled out on Optimism?

The migration from Kovan to Goerli will be rolled out in three phases:

  • Wave P0 - Infrastructure
  • Wave P1 - Projects (Building Block Apps)
  • Wave P2 - Projects (End-user Apps)

Because the migration is happening in phases, the Optimism team recommends teams, “use Optimism Goerli for any testing if you don’t require a hard dependency on anything not yet supported.”

Things to Consider Before Migrating from Opt-Kovan to Goerli

Before migrating smart contracts from Kovan to Goerli, dApp developers should consider their:

  1. Product roadmap - identify competing initiatives to plan the migration timing accordingly
  2. Upcoming deadlines - ensure the proper time of energy is available to migrate successfully
  3. Testing and verification needs - determine what testing and QA must be completed 
  4. Smart contract dependencies - review Kovan smart contract dependencies such as Aave v2

Web3 developers can ensure their Optimism dApps work as intended on Goerli by considering these areas and completing their migration to the new Opt-Goerli test network as soon as possible.

How to Migrate from Kovan to Goerli on Optimism

To migrate from Kovan to the Goerli testnet on Optimism, create a new app in the Alchemy dashboard with the “Chain” set to “Optimism” and the “Network” set to “Goerli.”

If you don’t already have an account, create a free Alchemy account to start testing on Optimism’s Goerli testnet.

Create a new Goerli app on Optimism from the Alchemy dashboard.

Next, copy the Optimism-Goerli RPC URL for your app. 

This is what the new Goerli RPC URL will look like: https://opt-goerli.g.alchemy.com/v2/<YOUR-API-KEY>

Copy the Optimism Goerli RPC URL from the Alchemy dashboard’s HTTPS section.

After you create a new Opt-Goerli RPC endpoint URL, you can request 0.05 Goerli ETH per day from Alchemy’s faucet. If you need more goETH, please email support at [email protected]

Goerli faucet for getting test ETH.

Before you can start testing smart contracts on the Opt-Goerli network, you need to bridge your test ETH from Ethereum to Optimism. 

How to Bridge Goerli ETH to Optimism

There is no public bridge to transfer Goerli ETH to Optimism yet, but it can be accomplished using Cast from Foundry, a toolkit for Ethereum application development. There is no user interface (UI) yet, but it is expected shortly.

Here is what an example code snippet would look like:

cast send --legacy --rpc-url=$ALCHEMY-OPT-GOERLI-ENDPOINT --value=0.001ether --private-key=<REDACTED> 0x636Af16bf2f682dD3109e60102b8E1A089FedAa8

Now that you have Goerli ETH on Optimism, deploy your Optimism smart contracts in the new Opt-Goerli app within Alchemy the same way you deployed your Kovan application.

Once your Optimism dApp is deployed on the Opt-Goerli testnet, you can continue running tests, debugging code, and iterating on your product the same way you did when testing it on Kovan

Additional Optimism Goerli Resources

For more information on the Optimism testnet migration from Kovan to Goerli, refer to these resources:

OPTIMISM GOERLI OVERVIEW

How to Migrate from Kovan to Goerli on Optimism

Migrating dApps and Bridging Goerli ETH to Optimism

The Optimism team recently announced the migration from Kovan to Goerli for their testnet. This article will explain why web3 developers building on Optimism should migrate their dApps to Goerli, and how to migrate with Alchemy, a developer platform that supports Optimism applications.

Why is Optimism migrating from Kovan to the Goerli testnet?

Kovan is a Proof-of-Authority (PoA) test network, and it has been deprecated for over a year. As of this announcement, there are only two remaining validators left supporting the Kovan testnet. 

To keep parity with the Ethereum network throughout The Merge roadmap, Optimism applications should migrate to Goerli, another Proof-of-Authority testnet that will be maintained after The Merge is complete later this year.

Other Ethereum testnets have already been deprecated (like Ropsten), will be deprecated later this year like the Rinkeby test network, the Kiln merge testnet, and the Prater testnet

For more information on Ethereum’s testnet deprecation and merge timeline, refer to the official Ethereum blog.

When will Optimism and Alchemy end support for Kovan?

Optimism is aiming for all projects to be completely migrated to Goerli by August 15th, 2022, and Alchemy will end support for the Kovan testnet on October 5th, 2022

As we approach the end of support for Kovan, Alchemy will inform current users through in-app alerts, email notifications, and direct messages to Enterprise customers about upcoming deadlines.

How will the migration from Kovan to Goerli be rolled out on Optimism?

The migration from Kovan to Goerli will be rolled out in three phases:

  • Wave P0 - Infrastructure
  • Wave P1 - Projects (Building Block Apps)
  • Wave P2 - Projects (End-user Apps)

Because the migration is happening in phases, the Optimism team recommends teams, “use Optimism Goerli for any testing if you don’t require a hard dependency on anything not yet supported.”

Things to Consider Before Migrating from Opt-Kovan to Goerli

Before migrating smart contracts from Kovan to Goerli, dApp developers should consider their:

  1. Product roadmap - identify competing initiatives to plan the migration timing accordingly
  2. Upcoming deadlines - ensure the proper time of energy is available to migrate successfully
  3. Testing and verification needs - determine what testing and QA must be completed 
  4. Smart contract dependencies - review Kovan smart contract dependencies such as Aave v2

Web3 developers can ensure their Optimism dApps work as intended on Goerli by considering these areas and completing their migration to the new Opt-Goerli test network as soon as possible.

How to Migrate from Kovan to Goerli on Optimism

To migrate from Kovan to the Goerli testnet on Optimism, create a new app in the Alchemy dashboard with the “Chain” set to “Optimism” and the “Network” set to “Goerli.”

If you don’t already have an account, create a free Alchemy account to start testing on Optimism’s Goerli testnet.

Create a new Goerli app on Optimism from the Alchemy dashboard.

Next, copy the Optimism-Goerli RPC URL for your app. 

This is what the new Goerli RPC URL will look like: https://opt-goerli.g.alchemy.com/v2/<YOUR-API-KEY>

Copy the Optimism Goerli RPC URL from the Alchemy dashboard’s HTTPS section.

After you create a new Opt-Goerli RPC endpoint URL, you can request 0.05 Goerli ETH per day from Alchemy’s faucet. If you need more goETH, please email support at [email protected]

Goerli faucet for getting test ETH.

Before you can start testing smart contracts on the Opt-Goerli network, you need to bridge your test ETH from Ethereum to Optimism. 

How to Bridge Goerli ETH to Optimism

There is no public bridge to transfer Goerli ETH to Optimism yet, but it can be accomplished using Cast from Foundry, a toolkit for Ethereum application development. There is no user interface (UI) yet, but it is expected shortly.

Here is what an example code snippet would look like:

cast send --legacy --rpc-url=$ALCHEMY-OPT-GOERLI-ENDPOINT --value=0.001ether --private-key=<REDACTED> 0x636Af16bf2f682dD3109e60102b8E1A089FedAa8

Now that you have Goerli ETH on Optimism, deploy your Optimism smart contracts in the new Opt-Goerli app within Alchemy the same way you deployed your Kovan application.

Once your Optimism dApp is deployed on the Opt-Goerli testnet, you can continue running tests, debugging code, and iterating on your product the same way you did when testing it on Kovan

Additional Optimism Goerli Resources

For more information on the Optimism testnet migration from Kovan to Goerli, refer to these resources:

ALCHEMY SUPERNODE - ETHEREUM NODE API

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Alchemy Supernode finally makes it possible to scale blockchain applications without all the headaches. Plus, our legendary support will guide you every step of the way.

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ALCHEMY SUPERNODE - ETHEREUM NODE API

Scale to any size, without any errors

Alchemy Supernode finally makes it possible to scale blockchain applications without all the headaches. Plus, our legendary support will guide you every step of the way.

Get started for free
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