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Worldcoin Foundation launches World Chain developer preview

5 Minute Read

World Chain is a new blockchain that prioritizes humans and is designed to scale with the growth of the Worldcoin project in support of all of humanity. 

The launch of the World Chain developer preview provides a unique opportunity for developers around the world to reach more than 10 million people across 160 countries who are using compatible wallets, starting with World App, built by project contributor Tools for Humanity (TFH). 

The preview is now open to a limited number of participants, interested developers can get access here

Reth, a high-performance Ethereum execution client developed by Paradigm, will operate in shadow mode during the developer preview, marking a first for Optimism.

Mint this announcement.

What can you expect from the developer preview?

The developer preview offers an opportunity for developers to explore, build, test and provide feedback on World Chain before its mainnet launch. It also enables builders to set up their deployments ahead of the migration of 10M+ users from OP Mainnet to World Chain expected later this summer. 

Built on the OP Stack and integrated with the Worldcoin protocol, World Chain is secured by Ethereum as an L2 and will be engineered for scalability as part of the Superchain ecosystem. 

Developers can start building on World Chain today ahead of a public launch later this year.

World Chain partners

World Chain is supported by a host of partners that are committed to delivering the best in-class tooling and infrastructure available to developers choosing to build on the chain, including Alchemy, Safe and Elliptic. Additional partnerships will be announced in the coming weeks, including node providers, analytics companies, wallet infrastructure providers, block explorers, bridges and many others. 

"We are dedicated to achieving self-custodial ownership for every human, and we’re thrilled to support World Chain with Safe's advanced smart account infrastructure. During the World Chain developer preview, developers can use Safe{Core} infrastructure to create exceptional user experiences for millions of verified humans on World Chain."
- Thibaut Sahaghian, Head of Network, Safe

“We're beyond excited to have Worldcoin, one of the largest projects in our space, build World Chain using Optimism's OP Stack, joining the Superchain and working alongside other core development groups to push the OP stack forward while contributing sequencer revenue to the Optimism Collective. The launch of World Chain’s developer preview marks a significant step forward, enabling Worldcoin’s developers to leverage the power of the OP Stack to build ambitious applications, further enhancing the Superchain's impact.”
- Ryan Wyatt, Chief Growth Officer, Optimism Unlimited


Why World Chain, why now?

World Chain aims to prioritize humans and will be the home for the Worldcoin network. It’s intended to be permissionless, open source and independently governed by the humans it represents.

World Chain will help unify the Worldcoin community by becoming the new base for all World ID integrations. The teams contributing to Worldcoin are already working alongside other core development groups to enhance and extend the OP Stack benefiting the entire Superchain ecosystem.

In addition, all World App users (currently numbering over 10 million) will be migrated onto World Chain later this year. World App users can send digital dollars around the world for free, connect to a service to explore and swap crypto tokens and (in eligible countries) claim Worldcoin Grants* within TFH’s World App.

World Chain will provide a platform for developers to offer users in Europe, Latin America, Asia, Africa and beyond access to a variety of applications that can improve their lives. These include interesting use cases around stablecoin finance, international remittances, commerce and ways to take advantage of a proof of humanness for users in these regions especially.

World Chain scalability

Scalability is a key focus for the teams building World Chain. 

The Worldcoin Foundation announced its support of Optimism and the Superchain prior to the network’s launch last July. In less than a year, Worldcoin user transactions have grown to about 50% of OP Mainnet’s activity, making it the largest application on the network, and one of the largest applications on any L2 of its kind. During peak periods, this can rise to over 80% and at times exceeds the practical limits of the chain. 


One of the key drivers for building World Chain is addressing the unprecedented scalability challenges that come with this growth. For this reason, while World Chain will launch initially with a standard EIP 1559 fee market, it will have a block gas target set to 10,000,000 (10MGas per block, or 5MGas/s, double that of the current OP Mainnet setting). 

The gas target is used by the fee market algorithm to adjust future fee calculations based on blockspace demand. What this means in practice is that World Chain will be able to process approximately double the amount of work as compared to OP Mainnet before the fee market is impacted.

While 5MGas/s is an immediate improvement, it is still far short of the efficiency levels World Chain will eventually need to reach in order to keep pace with the protocol’s projected growth. More than 10 million people in 160 countries have already created a World ID and a compatible wallet, which they’ve used to perform over 100 million transactions. [Millions of] people have also verified their World ID using an Orb. 

These numbers are expected to grow significantly and transaction volume will increase linearly with this growth. Without further optimizations, the demands of the community will exceed the capacity that can be managed effectively by adjusting block gas targets alone. 

For this reason, the Worldcoin Foundation and other contributors such as TFH are committing engineering resources to use Reth for the World Chain sequencer. Reth is a high-performance Ethereum execution client developed by Paradigm, which recently had its first production-ready release and security audit. It is written in Rust and designed to offer exceptional performance across all areas of the computing stack. The short-term goal with Reth (and related optimizations) is to get to 1,000 million gas per second, or 1GGas/s which represents a 400x increase over the current gas per second target of OP mainnet today.

“We are thrilled to help enable World Chain’s scaling roadmap with Reth, an SDK for building production-ready, high-performance blockchains. We look forward to working hand-in-hand with the Worldcoin Foundation, TFH, OP Stack and the rest of the community during the World Chain developer preview to achieve the ambitious mission of breaking through the 1GGas/s barrier and beyond.”
- Georgios Konstantopoulos, General Partner & CTO, Paradigm

World Chain will initially launch with Geth as the sequencer, the standard execution client for OP Stack chains. Reth will be operated in shadow mode to validate the blocks it produces against those generated by Geth. This marks a first for Optimism. Additionally, Worldcoin contributors are collaborating with OP Labs on ensuring a smooth rollout of the multi-client roadmap.

Safety, privacy and security are fundamental to the Worldcoin project and World Chain will be no exception. For this reason, in addition to a focus on scalability, World Chain will be one of the first chains to launch as a Stage 1 rollup, now that the initial fault proof system for Optimism is available on OP Stack. Fault proofs are a critical security feature that bolsters the integrity of transactions on an optimistic rollup. The process is designed to reliably identify and revert fraudulent transactions, maintaining the rollup's security, integrity, and decentralization.

Next steps

The World Chain developer preview gives developers the opportunity to begin building on the blockchain for humans in preparation for full launch soon. Interested developers can apply for access here

To get more information about the World Chain launch timeline, upcoming partnerships and more, join the daily conversations on Twitter/X, Telegram, Discord, YouTube and LinkedIn or sign up for the blog newsletter at the bottom of this page.

Additional important information concerning the project is available in the Worldcoin protocol whitepaper.


*Eligibility for Worldcoin (WLD) tokens is restricted based on geography, age, and other factors. WLD are not available to, or intended for, people, companies or organizations who are residents of, or are located or incorporated in the United States or certain other restricted territories (or have beneficial ownership in the United States or such other restricted territories). However, World ID and TFH’s World App remain available in the United States. For details, go to: www.worldcoin.org/tos. Crypto products can be highly risky. Important User Information can be found at www.worldcoin.org/risks.

The above content speaks only as of the date indicated. Further, it is subject to risks, uncertainties and assumptions, and so may be incorrect and may change without notice. A full disclaimer can be found in our Terms of Use and Important User Information can be found on our Risks page.