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
KINTSUGI OVERVIEW

What is the Kintsugi Testnet?

What is the Kintsugi testnet, Why was it created, and What Testnet to Use Now?
Last Updated:
May 24, 2022

As the Ethereum Foundation prepared to launch the long-anticipated consensus layer (ETH 2.0), the Kintsugi test network marked the first public exposure of the post-merge Ethereum environment with the transition to proof of stake. 

In this article, you’ll learn how the Kintsugi testnet originated and why it existed. You’ll also learn how to get and send testnet Ether and tools to kickstart your development.

WARNING: The Kintsugi testnet has been DEPRECATED. This article is purely informational. Instead, use the Sepolia testnet for testing smart contracts on a post-merge testnet.

What is the Kintsugi testnet?

The Kintsugi testnet was the first major test network to experiment and familiarize the public with Ethereum in its post-merge context. Launched in December 2021 after four short-lived testnets, the Kintsugi testnet was the first public network to undergo the Merge in preparation for the long-awaited consensus layer. 

Created and maintained by the Ethereum Foundation, the organization behind the community-driven development of the Ethereum chain, the Kintsugi merge testnet launched as a proof of work (PoW) network in parallel with a Beacon Chain running proof of stake (PoS). 

Throughout the Merge, the Kitsugi network then transitioned into using the PoS mechanism. As a public post-merge Ethereum testnet, Kintsugi sought to face rigorous tests for potential issues and attack vectors.

How was the Kintsugi testnet different from other testnets?

The Kintsugi testnet was designed specifically to test the Ethereum network after the merge of a PoW chain and the Beacon Chain. Hence, the network provided Ethereum developers with a safe environment to test their applications on a theoretical post-merge Ethereum chain and prepare for the consensus network. 

Other testnets exist for developers to test their applications and contracts before deploying on the PoS mainnet. As a developer, it boils down to their need to choose a certain testnet.

{{chart}}

The actual programming of applications on the testnet doesn’t change from the mainnet. The Kintsugi testnet maintained the same developer experience as the mainnet. Ethereum launched the testnet to catch any edge cases of a post-merge PoS Ethereum chain.

What happened to the Kintsugi testnet?

The Kintsugi testnet was designed to identify major bugs with the post-Merge Ethereum environment. During the testing phase, it was forked into multiple chains causing it to be deprecated in favor of a new post-merge testnet, Kiln.

A month after the launch, the Kintsugi testnet hit a significant roadblock. Among countless tests and attack vectors the testnet underwent, Marius van der Wijden, an Ethereum core developer with the Geth client team, was able to cause the network to split twice. 

By altering the hash of a newly submitted block to its parent hash, van der Wijden’s test forced conflicts between different Ethereum clients. Whereas the expected result was all clients rejecting such a faulty block, some clients accepted the block as it used the cache of the valid parent block. 

The Geth clients rejected the fault block, while Nethermind and Besu clients accepted the block, leading to the first split. Then, some Geth nodes running variations of the client disagreed on the result internally, causing the second network split.

Because the Kintsugi network lost the ability to finalize transactions due to multiple forks, the Ethereum Foundation introduced the Kiln Merge testnet in March 2022 to test the Merge once again, hoping to transition existing long-lived testnets finally. 

Since then, the Kintsugi testnet has been deprecated, and the Kiln network was used to carry out the first mainnet ‚Äúshadow fork.‚ÄĚ

Conclusion

The launch of the Kintsugi testnet marked a significant milestone for the Ethereum Foundation in completing The Merge. By opening the Kintsugi testnet up to Web3 developers, the Ethereum Foundation onboarded existing developers to deploy applications and battle-test the network with edge cases.

Although the Kintsugi network was deprecated in favor of the Kiln merge testnet, the network served its purpose of catching significant bugs. 

To get testnet ETH on popular testnets, create a free Alchemy account. To learn more about testnets, visit Alchemy’s ever-expanding catalog of developer resources on Ethereum.

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Testnets
KINTSUGI OVERVIEW

What is the Kintsugi Testnet?

What is the Kintsugi testnet, Why was it created, and What Testnet to Use Now?
Last Updated:
May 24, 2022
Last Updated:
March 14, 2023
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Table of Contents

As the Ethereum Foundation prepared to launch the long-anticipated consensus layer (ETH 2.0), the Kintsugi test network marked the first public exposure of the post-merge Ethereum environment with the transition to proof of stake. 

In this article, you’ll learn how the Kintsugi testnet originated and why it existed. You’ll also learn how to get and send testnet Ether and tools to kickstart your development.

WARNING: The Kintsugi testnet has been DEPRECATED. This article is purely informational. Instead, use the Sepolia testnet for testing smart contracts on a post-merge testnet.

What is the Kintsugi testnet?

The Kintsugi testnet was the first major test network to experiment and familiarize the public with Ethereum in its post-merge context. Launched in December 2021 after four short-lived testnets, the Kintsugi testnet was the first public network to undergo the Merge in preparation for the long-awaited consensus layer. 

Created and maintained by the Ethereum Foundation, the organization behind the community-driven development of the Ethereum chain, the Kintsugi merge testnet launched as a proof of work (PoW) network in parallel with a Beacon Chain running proof of stake (PoS). 

Throughout the Merge, the Kitsugi network then transitioned into using the PoS mechanism. As a public post-merge Ethereum testnet, Kintsugi sought to face rigorous tests for potential issues and attack vectors.

How was the Kintsugi testnet different from other testnets?

The Kintsugi testnet was designed specifically to test the Ethereum network after the merge of a PoW chain and the Beacon Chain. Hence, the network provided Ethereum developers with a safe environment to test their applications on a theoretical post-merge Ethereum chain and prepare for the consensus network. 

Other testnets exist for developers to test their applications and contracts before deploying on the PoS mainnet. As a developer, it boils down to their need to choose a certain testnet.

{{chart}}

The actual programming of applications on the testnet doesn’t change from the mainnet. The Kintsugi testnet maintained the same developer experience as the mainnet. Ethereum launched the testnet to catch any edge cases of a post-merge PoS Ethereum chain.

What happened to the Kintsugi testnet?

The Kintsugi testnet was designed to identify major bugs with the post-Merge Ethereum environment. During the testing phase, it was forked into multiple chains causing it to be deprecated in favor of a new post-merge testnet, Kiln.

A month after the launch, the Kintsugi testnet hit a significant roadblock. Among countless tests and attack vectors the testnet underwent, Marius van der Wijden, an Ethereum core developer with the Geth client team, was able to cause the network to split twice. 

By altering the hash of a newly submitted block to its parent hash, van der Wijden’s test forced conflicts between different Ethereum clients. Whereas the expected result was all clients rejecting such a faulty block, some clients accepted the block as it used the cache of the valid parent block. 

The Geth clients rejected the fault block, while Nethermind and Besu clients accepted the block, leading to the first split. Then, some Geth nodes running variations of the client disagreed on the result internally, causing the second network split.

Because the Kintsugi network lost the ability to finalize transactions due to multiple forks, the Ethereum Foundation introduced the Kiln Merge testnet in March 2022 to test the Merge once again, hoping to transition existing long-lived testnets finally. 

Since then, the Kintsugi testnet has been deprecated, and the Kiln network was used to carry out the first mainnet ‚Äúshadow fork.‚ÄĚ

Conclusion

The launch of the Kintsugi testnet marked a significant milestone for the Ethereum Foundation in completing The Merge. By opening the Kintsugi testnet up to Web3 developers, the Ethereum Foundation onboarded existing developers to deploy applications and battle-test the network with edge cases.

Although the Kintsugi network was deprecated in favor of the Kiln merge testnet, the network served its purpose of catching significant bugs. 

To get testnet ETH on popular testnets, create a free Alchemy account. To learn more about testnets, visit Alchemy’s ever-expanding catalog of developer resources on Ethereum.

As the Ethereum Foundation prepared to launch the long-anticipated consensus layer (ETH 2.0), the Kintsugi test network marked the first public exposure of the post-merge Ethereum environment with the transition to proof of stake. 

In this article, you’ll learn how the Kintsugi testnet originated and why it existed. You’ll also learn how to get and send testnet Ether and tools to kickstart your development.

WARNING: The Kintsugi testnet has been DEPRECATED. This article is purely informational. Instead, use the Sepolia testnet for testing smart contracts on a post-merge testnet.

What is the Kintsugi testnet?

The Kintsugi testnet was the first major test network to experiment and familiarize the public with Ethereum in its post-merge context. Launched in December 2021 after four short-lived testnets, the Kintsugi testnet was the first public network to undergo the Merge in preparation for the long-awaited consensus layer. 

Created and maintained by the Ethereum Foundation, the organization behind the community-driven development of the Ethereum chain, the Kintsugi merge testnet launched as a proof of work (PoW) network in parallel with a Beacon Chain running proof of stake (PoS). 

Throughout the Merge, the Kitsugi network then transitioned into using the PoS mechanism. As a public post-merge Ethereum testnet, Kintsugi sought to face rigorous tests for potential issues and attack vectors.

How was the Kintsugi testnet different from other testnets?

The Kintsugi testnet was designed specifically to test the Ethereum network after the merge of a PoW chain and the Beacon Chain. Hence, the network provided Ethereum developers with a safe environment to test their applications on a theoretical post-merge Ethereum chain and prepare for the consensus network. 

Other testnets exist for developers to test their applications and contracts before deploying on the PoS mainnet. As a developer, it boils down to their need to choose a certain testnet.

{{chart}}

The actual programming of applications on the testnet doesn’t change from the mainnet. The Kintsugi testnet maintained the same developer experience as the mainnet. Ethereum launched the testnet to catch any edge cases of a post-merge PoS Ethereum chain.

What happened to the Kintsugi testnet?

The Kintsugi testnet was designed to identify major bugs with the post-Merge Ethereum environment. During the testing phase, it was forked into multiple chains causing it to be deprecated in favor of a new post-merge testnet, Kiln.

A month after the launch, the Kintsugi testnet hit a significant roadblock. Among countless tests and attack vectors the testnet underwent, Marius van der Wijden, an Ethereum core developer with the Geth client team, was able to cause the network to split twice. 

By altering the hash of a newly submitted block to its parent hash, van der Wijden’s test forced conflicts between different Ethereum clients. Whereas the expected result was all clients rejecting such a faulty block, some clients accepted the block as it used the cache of the valid parent block. 

The Geth clients rejected the fault block, while Nethermind and Besu clients accepted the block, leading to the first split. Then, some Geth nodes running variations of the client disagreed on the result internally, causing the second network split.

Because the Kintsugi network lost the ability to finalize transactions due to multiple forks, the Ethereum Foundation introduced the Kiln Merge testnet in March 2022 to test the Merge once again, hoping to transition existing long-lived testnets finally. 

Since then, the Kintsugi testnet has been deprecated, and the Kiln network was used to carry out the first mainnet ‚Äúshadow fork.‚ÄĚ

Conclusion

The launch of the Kintsugi testnet marked a significant milestone for the Ethereum Foundation in completing The Merge. By opening the Kintsugi testnet up to Web3 developers, the Ethereum Foundation onboarded existing developers to deploy applications and battle-test the network with edge cases.

Although the Kintsugi network was deprecated in favor of the Kiln merge testnet, the network served its purpose of catching significant bugs. 

To get testnet ETH on popular testnets, create a free Alchemy account. To learn more about testnets, visit Alchemy’s ever-expanding catalog of developer resources on Ethereum.

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