The Kintsugi 🍵 merge testnet, which launched in late December, has served as a valuable testing ground for The Merge. It has gone through various test suites, multi-client devnets, shadow forks of Goerli, application deployments, and community support under #TestingTheMerge. This has resulted in stable and robust protocol specifications. Now that clients have implemented these latest specifications, a successor to Kintsugi, Kiln 🔥🧱, is being launched!
Similar to the Ethereum mainnet, Kiln’s execution layer was launched with proof-of-work alongside a Beacon Chain running proof-of-stake. The merge took place on Kiln on March 15, 2022. The network is now fully operating under proof-of-stake!
Kiln is expected to be the final merge testnet before existing public testnets are upgraded. Application & tooling developers, node operators, infrastructure providers, and stakers are strongly encouraged to test on Kiln to ensure a smooth transition on existing public testnets.
In the coming weeks, Kintsugi, the previous merge testnet, will be deprecated.
The easiest way to get started with Kiln is to visit the network’s landing page. There, you can add the network to your browser wallet, view block explorers, request funds from the faucet, and connect to a JSON RPC endpoint. If you’d like to become a validator on Kiln, the staking launchpad also supports the network.
Application & Tooling Developers
With Kiln going live, now is the time to ensure that your product works as expected during the proof-of-stake transition and in a post-merge context. As explained in a previous post, The Merge will have minimal impact on a subset of contracts deployed on Ethereum, and there should be no breaking changes. Additionally, the majority of user API endpoints will remain stable (unless you are using PoW specific methods such as eth_getWork).
However, most Ethereum applications involve more than on-chain contracts. Kiln is where you can ensure that your front-end code, tooling, deployment pipeline, and other off-chain components work as intended. We strongly recommend that developers go through a full testing & deployment cycle on Kiln and report any issues with tools or dependencies to the respective maintainers of those projects. If you’re unsure about where to open an issue, please use this repository.
After The Merge, an Ethereum full node will consist of a consensus layer client, which runs proof-of-stake on the Beacon Chain, and an execution layer client, which manages the user-state and performs computations related to transactions. These clients communicate over an authenticated port using a new set of JSON RPC methods known as the Engine API.
Node operators will need to run both a consensus and execution layer client simultaneously. In other words, if you were already running a node on the Beacon Chain, you will now also need to run an execution layer client. Similarly, if you were running a node on the current proof-of-work network, you will need to run a consensus layer client.
You can find the latest Kiln-supported releases of clients here.
It’s important to note that each layer will have its own set of peers and expose its own APIs. Therefore, the Beacon and JSON RPC APIs will continue to work as expected.
As mentioned earlier, validators on the Beacon Chain will need to run an execution layer client after The Merge. It was strongly recommended before the merge, but validators could outsource these functions to third-party providers. This was possible because the only data required on the execution layer were updates to the deposit contract.
Post-merge, validators need to ensure that the transactions in the blocks they create and attest to are valid. To do this, an execution layer client is required. While this expands validators’ responsibilities, it also gives the validator who proposes a block the right to its associated transaction priority fees (which currently go to miners).
While validator rewards accrue on the Beacon Chain and will require a subsequent upgrade for withdrawal, transaction fees will continue to be paid, burned, and distributed on the execution layer. Validators can designate any Ethereum address as the recipient of transaction fees.
Kiln provides the perfect environment for existing stakers to familiarize themselves with the post-merge Ethereum context. We recommend trying to replicate your production setup on the network and addressing any issues now.
Once again, the staking launchpad offers a simple interface to get started. Note that as part of the renaming away from “eth2.0”, the ethereum/eth2.0-deposit-cli repository will soon be renamed to ethereum/staking-deposit-cli.
When is the merge happening?
As of the publication of this post, a date for the Ethereum mainnet proof-of-stake transition has not been set. Any source claiming otherwise is likely a scam. Updates will be posted on this blog. Please stay safe!
Assuming no issues are found with Kiln, once clients have finalized the details of their implementations, the existing Ethereum testnets (Goerli, Ropsten, etc.) will undergo The Merge. After these testnets have successfully transitioned and stabilized, assuming no issues are found, a difficulty value will be set for the mainnet transition. Only then will it be possible to estimate the exact date for The Merge.
As an Ethereum user or holder of Ether, do I need to do anything?
No. If you want to try out Kiln, please go ahead. We hope that many community members will join us in #TestingTheMerge on Kiln.
This testnet does not affect the Ethereum mainnet. Subsequent announcements will be made on this blog prior to the mainnet’s transition.
As a miner, do I need to do anything?
No. If you are mining on the Ethereum mainnet, please be aware that after The Merge, the network will operate solely under proof-of-stake. At that point, mining will no longer be possible on the network.
As a validator, can I withdraw my stake?
No. The Merge is the most complex upgrade to Ethereum to date. To minimize the risk of network disruptions, this upgrade focused only on the transition and excluded any non-transition changes.
Withdrawals from the Beacon Chain will likely be available after the first upgrade following The Merge. Specifications for both the consensus and execution layers are currently being developed.
Why the name Kiln?
The previous merge testnet, Kintsugi, was named after the Japanese art of repairing broken pottery with gold, making it stronger and more beautiful.
Similarly, a Kiln is a high