The Ethereum Foundation's Protocol Support Team confirmed on June 21, 2022 that it will retire the Ropsten, Rinkeby, and Kiln testnets in a phased wind-down tied to the upcoming Merge, the network's long-planned transition from energy-intensive proof-of-work mining to proof-of-stake validation. Testnets are parallel blockchain environments that let developers build and test smart contracts without spending real ETH or risking funds on the main network. Their shutdown leaves Goerli and Sepolia as the two officially supported options going forward.

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What Is Being Shut Down and When

The three networks face different timelines. Kiln, a short-lived testnet built specifically to rehearse the Merge, will be retired immediately after the mainnet Merge completes. Ropsten, Ethereum's longest-running testnet at nearly six years old, completed its own transition to proof-of-stake on June 8, 2022, making it the first Ethereum testnet to make that shift. It is scheduled for shutdown in Q4 2022.

Rinkeby, a network launched in 2017 and built exclusively around the go-ethereum client, will follow in Q2 or Q3 of 2023.

Rinkeby will not receive a proof-of-stake upgrade at all. "After The Merge, Rinkeby will not be a suitable testing environment for the Ethereum mainnet," the Protocol Support Team wrote. The Foundation cited developer bandwidth as a key factor behind the consolidation. Client developers, the team stated, need to "focus their efforts on properly maintaining two of them over the long-term."

Ropsten, named after a Stockholm metro station and launched in November 2016, held a unique place in Ethereum's history as the only testnet that fully replicated the main network's proof-of-work consensus. (The only testnet predating Ropsten was Morden, launched in 2015 and later closed due to replay attack vulnerabilities.) That characteristic made it the most realistic testing environment available for the better part of six years.

Etherscan, the dominant Ethereum block explorer, formally announced deprecation of its Ropsten and Rinkeby support in October 2022, reinforcing the Foundation's wind-down timeline and signaling to the broader developer ecosystem that the shift was irreversible.

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Gray Glacier and the Difficulty Bomb

The Ethereum Foundation announced the Gray Glacier upgrade on June 16, 2022, five days before the testnet deprecation announcement. The upgrade targeted block 15,050,000 and was expected to execute around June 29, 2022.

The upgrade's purpose is to delay the "difficulty bomb," a built-in protocol mechanism that gradually raises mining difficulty until it becomes impractical, nudging miners toward accepting network upgrades. Gray Glacier pushes this back by 700,000 blocks, or roughly 100 days, buying time for the Merge to complete before the bomb makes proof-of-work mining unworkable.

Node operators were given until June 27, 2022 to update their client software to avoid disruption. Ethereum developer Tim Beiko expressed hope that this would be the last time the mechanism requires delaying, given that Gray Glacier follows similar postponements through upgrades including Byzantium, Constantinople, Muir Glacier, London, and Arrow Glacier.

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The Migration Burden Falls Hardest Outside North America

For developers in emerging markets, the deprecation is more than an administrative inconvenience. In Nigeria, Kenya, India, and other high-growth developer regions, testnets serve as the primary entry point into Ethereum development. High gas costs on the main network and limited access to ETH through local exchanges in many emerging markets make test environments the only practical place to build and learn.

The practical consequences of the shutdown are several. Faucets (services that distribute free test tokens) linked to Ropsten across widely used educational platforms will stop working. Developers will need to update RPC endpoints (the network connection addresses used in their code) to point to Goerli or Sepolia. Any smart contracts already deployed on Ropsten or Rinkeby will need to be redeployed on a new network, adding overhead for small teams with no dedicated infrastructure support.

Alchemy, one of the largest Ethereum infrastructure providers, moved its own Ropsten cutoff to July 1, 2022, well ahead of the official Q4 timeline. That earlier deadline created immediate pressure for developers who had assumed they had until Q4 to complete their migrations. The company's free-tier Goerli access allocates 0.02 test ETH per day, a modest but meaningful resource for developers in cost-sensitive markets.

According to Electric Capital's 2022 developer report, 72 percent of all crypto developers were based outside North America that year. The same report separately identified Nigeria and India among the fastest-growing contributors to Ethereum's global developer base.

The Africa Blockchain Center graduated its first cohort of 105 developers in December 2022, the same quarter Ropsten went offline, underscoring how active the pipeline was precisely when the tooling was shifting underneath it.

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Where Developers Should Go Now

The Ethereum Foundation recommends Goerli for stakers and developers who need a large existing chain state similar to mainnet, and Sepolia for those who want a lightweight environment that syncs quickly and is suited for direct contract testing.

Developers who migrated to Goerli in mid-2022 faced a further complication: Goerli itself was flagged for deprecation as early as Q1 2023. As of 2026, Sepolia remains the primary maintained Ethereum testnet, making it the more durable long-term choice even if it carried less tooling support at the time of the original announcement.

"Developers who currently use Ropsten as a staging or testing environment should migrate to Goerli or Sepolia," the Protocol Support Team wrote in its June 21 announcement. For a global developer community still building on top of tutorials and curricula that defaulted to Ropsten, particularly in high-growth markets such as India and Nigeria, that migration was not always as straightforward as the guidance implied.