Introducing Polygon Chain Development Kit (CDK): Launch ZK L2s On Demand to Unlock Unified Liquidity

TL;DR: 

• Polygon CDK is an open source codebase for launching ZK-powered L2 chains for Ethereum, on demand
• All chains deployed using Polygon CDK are interoperable, with automatic access to the unified liquidity of all Polygon chains, and one-click access to the entire liquidity of Ethereum
• Core modularity means developers can use Polygon CDK to design networks according to their needs
• Zero-knowledge proofs ensure cryptographic security and near-instant finality 

At the heart of Polygon 2.0’s vision is a web of ZK-powered L2s that are seamlessly interconnected and able to scale Ethereum on demand. But building and launching L2s is complex. It requires protocol-level knowledge, bootstrapping sequencer(s), and various other infrastructure-related operations, all of which pose unique challenges for developers.

Enter Polygon CDK (Chain Development Kit). Polygon CDK is an open-source and modular codebase that anyone, anywhere can use to launch their own L2 chain, powered by the industry-leading ZK-technology of Polygon. 

Any developer deploying a chain using Polygon CDK will be launching a ZK-powered L2 on Ethereum. By connecting to a shared ZK bridge, every chain is also seamlessly interoperable – connected to every other. Together, these chains form the value layer of the internet.

Polygon CDK is the evolution of Supernets, which offered projects the ability to operate sidechain-like appchain protocols. Polygon CDK takes appchain design to a new level, enabling easy deployment of interoperable, ZK-powered Ethereum L2s. Using CDK, all existing Supernets can upgrade their current architecture to the industry-leading Polygon ZK technology.

Are you a developer? Checkout CDK’s GitHub and begin designing your ZK L2 right now.

Existing appchain solutions either produce walled gardens with isolated liquidity, or offer interoperability with significant latency and additional security assumptions and concerns. These limitations are due to the architecture and technology of existing solutions. Some utilize different proving systems, such as fraud proofs, which significantly delay finality and cannot offer fast interoperability. Others offer L3 solutions that settle on an L2 (which then settles on Ethereum), which increases complexity and fragments liquidity. Some solutions are building separate, competing ecosystems to Ethereum, meaning they cannot leverage Ethereum’s liquidity and security. No appchain solution exists that offers high security, seamless interoperability and access to liquidity of Ethereum and all other participating chains.

Polygon 2.0 changes this with its vision of the Value Layer of the Internet, and Polygon CDK allows anyone to join that vision.

Anyone can leverage Polygon CDK to plug their chain (whether currently in existence or being built) into the value layer on Polygon in a seamless and fully permissionless manner. This provides a wide range of benefits:

• Secure and near-instant interoperability with all other Polygon chains; 
• Automatic, seamless access to shared liquidity of all Polygon chains; 
• Fast, one-click access to the entire liquidity of Ethereum;
• Access to production-ready and lightning-fast Polygon proving and proof aggregation technology. 

Practically speaking, chains that decide to use Polygon CDK tap into a seamlessly integrated, ever-expanding ecosystem of ZK-powered L2s on Ethereum, becoming a part of the Value Layer of the Internet. 

All these chains share access to the unified liquidity of public networks like Polygon PoS and Polygon zkEVM, as well as all the current and future app-specific chains in the Polygon ecosystem. 

Participating chains benefit from the massive liquidity that exists across all networks, while maintaining the highest levels of scalability, security and sovereignty. 

Let’s dive into an overview of Polygon CDK and see what’s possible.

What is Polygon CDK?

Polygon CDK is an open-source codebase, with modularity at its core. Devs can use this codebase to launch ZK-powered Ethereum L2 chains, or to convert existing L1 chains to L2 chains. All these L2s are interconnected with one another and with Ethereum, benefiting from near-instant finality, unlimited scalability, and unified liquidity. 

Developers can build chains according to whatever specifications they desire. 

What are the value props of Polygon CDK?

Polygon CDK unlocks entirely new value propositions for blockchains: 

1. High modularity and customizability
2. Seamless interoperability and shared liquidity 
3. Bleeding-edge, future proof ZK technology 

Modularity and customizability. Polygon CDK offers a modular environment for ZK-powered L2 chain design. Devs can tailor-make chains according to their requirements by choosing Polygon CDK components: 

• Rollup or validium mode; 
• zkEVM or another ZK-powered execution environment (e.g. MidenVM);
• Various data availability solutions;
• Native token and gas token customization;
• Centralized or (on the roadmap) decentralized sequencer mode;
• Permissioned networks with granular allowlists;
• Configurable time to post ZK proofs to Ethereum;

And more.

A hypothetical example: An NFT-specific appchain can select zkEVM execution environment, choose “validium” mode, and opt for a centralized sequencer. For data availability, a local DAC (Data Availability Committee) can be selected. The devs can then tinker with the time between posting ZK proofs to Ethereum, thus optimizing running costs. Finally, they can decide what token may be used for gas. Importantly, despite all these customizations, this hypothetical NFT Chain is still able to seamlessly interoperate and share liquidity with all other Polygon chains. 

The modularity of Polygon CDK offers flexibility to meet any requirement, without sacrificing scalability or fracturing liquidity. 

Seamless interoperability and shared liquidity. Every chain developed using Polygon CDK is by design connected with every other Polygon chain. As a result, users and developers can seamlessly transact or move across chains. Native interoperability meets automatic, shared liquidity.

The core technical component that makes this possible is Polygon 2.0’s Interop Layer. The Interop Layer is a novel protocol that accepts ZK proofs from Polygon chains, aggregates them, and posts the aggregated proof and updated chain states to Ethereum. It can be understood as a ZK-secured coordinator of chain states, guaranteeing composability and allowing unified liquidity at scale. 

In practice, this allows for near-instant finality and cross-chain execution among all CDK-developed chains, regardless of their mode (rollup or validium), execution environment (zkEVM or another ZK-powered VM), and other configurations. A ZK-powered L2 network also means withdrawals to Ethereum are fast, taking minutes instead of days. 

Users of any CDK-developed chain are automatically plugged into the entirety of the Value Layer, a mesh of networks with interactivity possible across all participating chains, Ethereum included. 

Bleeding edge and future-proof ZK tech. Polygon leads the industry in fast, efficient ZK technology, from performant and production-ready proof systems to the EVM-equivalent zkEVM. Chains deployed using Polygon CDK benefit from core development work, which is constantly hardening the underlying codebase. 

As a result, all chains built using CDK become future-proof by default: state-of-the-art Polygon ZK advancements will be automatically available in CDK, too. 

The future is more secure with ZK. Chains deployed using Polygon CDK rely on the security of cryptography, rather than the social requirements and incentives necessary in fraud proofs. No need for users to run full nodes that check whether or not transactions are valid – chain states are proved by math. 

This powerful technology is what makes the Value Layer secure, interconnected and infinitely scalable.

Fitting into the Polygon 2.0 Vision

Over the last several months, Polygon 2.0 was introduced in a series of posts that reimagine every aspect of the Polygon technical ecosystem.

The goal is simple: build the value layer of the internet, a core protocol that makes creating, sending, and receiving value of any kind as seamless and functional as sending or receiving information over the Internet. At the heart of this vision is ZK architecture that enables infinite scalability and seamless interconnectivity without sacrificing security. Spinning up new chains to meet demand in this environment should be as easy as spinning up new servers. 

Polygon CDK unlocks the vision of the Value Layer, offering an easy-to-use environment for launching Polygon chains. We are excited for what all the talented builders out there will create with it, so make sure to check out the documentation for Polygon CDK to begin experimenting today and be sure to tune into the blog for all things Polygon 2.0.

Together, we can build an equitable future for all through the mass adoption of Web3!

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