Original Author: Yuki, PaperMoon
From the initial Substrate to the current Polkadot SDK, Polkadot's goal has never been to pursue the ultimate performance of a single chain, but to build a universal foundation that serves heterogeneous multi-chains, allowing anyone to create their own blockchain as easily as building with blocks.
This system emphasizes not compatibility, but composability; not single-point optimization, but system-level collaboration. It provides future developers with a "reusable underlying order" through modular governance, security mechanisms, and native cross-chain protocols (XCM).
As Gavin Wood stated, Polkadot is not "a new chain for compatibility," but a chain-building system that serves ecological innovation and a multi-chain future. The Polkadot SDK is the latest form of this machine, a unified interface, standardized development stack, and cross-VM chain-building engine.
The History and Limitations of Substrate
Substrate was launched by Parity in 2018 as a modular blockchain development framework written in Rust, providing the core technological foundation for dozens of chains in the Polkadot mainnet and ecosystem. Its greatest innovation lies in splitting consensus algorithms, runtime logic, account models, asset governance, smart contracts, and more into freely combinable pallet modules. Any team can assemble a customized blockchain like building blocks, making Substrate the industry's first true Layer-0 Framework.
Polkadot Substrate pioneered the transformation of building a chain from an independent and closed design logic into a "open Lego" customizable blockchain. Developers can freely assemble governance, staking, contracts, identity, DEX, and other functional modules through the FRAME system, achieving "chain-level modular development" and quickly building application chains aimed at DeFi, NFT, DID, and other scenarios.
This design allowed the early Polkadot ecosystem to give birth to a rich variety of chain-level innovations in a very short time.
However, the high degree of customization freedom brought about a fragmentation burden at the ecological level. After years of iteration, the code and functions for building a parachain became scattered across multiple code repositories, such as Substrate, Cumulus, and Polkadot. Each project relied on different versions and used different branches, leading to severe fragmentation of the API and documentation system.
To avoid conflicts in the main branch, many teams could only fork their own runtimes and manually maintain versions, resulting in difficulties for the ecosystem to converge, complex inter-library synchronization, and delayed version updates. As the underlying dependencies and interfaces evolved separately, the entire ecosystem fell into three major bottlenecks:
● Difficult upgrades: The main branch progresses slowly, module updates require manual synchronization, and many chains remain on old versions for a long time.
● Difficult collaboration: Runtimes from different teams cannot be reused directly, and cross-chain or shared module development requires repetitive labor.
● Difficult dissemination: Documentation and toolchains are fragmented, the learning curve is steep, and new developers find it hard to systematically master chain-level development.
The end result is that the modular freedom of Substrate has instead created a fragmented constraint at the ecological level. For this reason, Parity took a crucial step: unifying and integrating all core modules, interfaces, and repositories into a complete, standardized Polkadot SDK.
The Birth of Polkadot SDK: Reconstructing a Unified Framework
After years of fragmented collaboration, Parity ultimately chose to undertake a historic architectural integration in 2023-2024.
The official announcement merged Substrate, Cumulus, Polkadot (as well as FRAME and node-related repositories) into a single codebase: Polkadot SDK. 
For a long time, the independent evolution of multiple repositories consumed significant energy for developers in cross-project collaboration, dependency updates, and version management.
Polkadot SDK completely eliminates the frequent synchronization and conflicts between multiple repositories through unified dependency management, standardized development specifications, and synchronized code update mechanisms.
Parity clearly stated in the merger announcement that this step aims to make Substrate no longer just a "flexible engineering framework," but a standardized protocol stack supporting the entire Polkadot ecosystem. The new Polkadot SDK library integrates all core components of Polkadot:
● Substrate: Provides blockchain runtime, consensus, and core modules;
● FRAME: Constructs the pallet module system, achieving pluggable runtime logic;
● Cumulus: Serves as a parachain adaptation layer, allowing chains to connect directly to the relay chain;
● Polkadot Node: Defines the main node protocol stack and network communication logic.
Core Technical Structure of Polkadot SDK
All modules, dependencies, and documentation systems are now unified in one repository, with complete migration documentation and update history.
This means developers no longer need to search, piece together, and debug across multiple codebases, but can build, debug, and deploy an entire chain in a unified environment, elevating the developer experience from "flexible modularity" to "fully composable across the ecosystem."
The merged Polkadot SDK has received widespread recognition from developers and the ecological community.
It not only leads the backbone of future chain-level innovations in Polkadot but also allows developers to more easily build their own Appchain or Rollup in a modular way.
The documentation system, API structure, and building tools are fully unified, significantly lowering the learning curve and greatly improving collaboration efficiency.
For Parity, this integration represents a significant architectural evolution since the genesis of Polkadot; for the entire ecosystem, the Polkadot SDK marks the true beginning of transitioning from "multi-chain coexistence" to "multi-chain collaboration." Substrate provided the freedom to build chains, while the SDK provided ecological order.
From SDK to REVM: The Inevitable Result of EVM Nativization
Native EVM has received native support on Polkadot. The emergence of REVM allows chains based on the Polkadot SDK to easily incorporate all functionalities of Ethereum. It signifies that Polkadot no longer relies on any external EVM compatibility solutions, but directly integrates the core execution environment of the Ethereum ecosystem into its own system.
In the early Polkadot ecosystem, EVM compatibility was handled independently by each parachain. Chains like Moonbeam, Astar, and Acala all adopted the Frontier framework provided by Parity, a modular solution for implementing EVM functionalities. This model granted parachains high flexibility but also led to engineering fragmentation, as each chain needed to independently maintain the Frontier module, manage RPC compatibility, debug EVM logic, and fix compatibility issues.
The Parity team embedded the EVM engine directly into the SDK core in the form of REVM, placing it alongside FRAME, Cumulus, and XCM as core modules. EVM compatibility, which was previously an external project for each parachain, has officially been integrated into the system core, becoming a standard capability of Polkadot.
REVM is rewritten by Parity in Rust, natively adapting to the Polkadot SDK architecture. Its birth is not an additional compatibility layer, but a system-level integration.
Core features include:
● Rust implementation: High performance, memory safety, and seamless collaboration with other SDK components;
● Native integration: REVM is directly compiled into the Polkadot SDK, eliminating the need for the Frontier plugin;
● Unified developer experience: Compatible with the entire Ethereum toolchain (Foundry, Hardhat, Ethers.js), allowing developers to use existing Ethereum tools "out of the box";
● Zero migration cost: Solidity contracts can be deployed to the Polkadot mainnet or any SDK chain without modification;
● Ecological-level unification: All new chains inherently possess EVM execution capabilities, no longer relying on individual projects like Moonbeam for compatibility entry.
This means that the deployment and execution of EVM contracts will for the first time become a native feature at the Polkadot mainnet level.
The emergence of REVM is not the result of external competition, but an inevitable product of SDK integration. When the underlying modules and protocol implementations are thoroughly standardized, EVM compatibility will naturally be absorbed as a system standard rather than an additional plugin. This also marks Polkadot's first true "absorption of Ethereum" at the execution layer, achieving a leap from "compatibility" to "native."
By 2025, Parity decided to rewrite the entire development framework.
The new Polkadot SDK not only inherits the soul of Substrate but also directly compiles Ethereum's EVM into the core.
This is not just a version iteration, but a reconstruction of the concept—
Polkadot is no longer just compatible with Ethereum; it absorbs it, making it a native part.
But the question is—Polkadot could have continued to maintain the status quo; why take the risk of rewriting the entire SDK in 2025 and placing the EVM directly into the system core?
Substrate was initially launched by Parity (the core development company of Polkadot) as a Rust modular blockchain development framework for building any blockchain, including core modules such as consensus, storage, networking, and runtime, serving as the underlying technological foundation of the Polkadot network.
Between 2023 and 2024, Parity unified and merged Substrate, Cumulus (cross-chain module), Polkadot client, and other projects into a single repository, named Polkadot SDK (Software Development Kit), to simplify the development structure and API management.
This integration allows developers to complete all development work related to chain-level modules, consensus, cross-chain, nodes, assets, and governance using a single SDK main repository, transitioning from "multiple projects using the same library" to "integrated development of a unified stack."
Currently, the core components of the Polkadot SDK are:
In the future, REVM will serve as a virtual machine backend (VM backend) module supporting EVM (i.e., Ethereum Virtual Machine) within the PolkaVM / PVM ecosystem, forming part of the "EVM compatibility solution" along with pallet-revive + ETH-RPC, among others.
In the latest iteration of the Polkadot SDK, REVM has been explicitly included as a core component (i.e., a standard module for smart contract execution), meaning that all SDK chains will automatically support REVM/EVM in the future without the need for third-party plugins or compatibility packages. The strategy of "REVM providing native EVM compatibility for the Polkadot ecosystem" has been solidified in the main codebase and official development documentation.
The Technical Core of Polkadot SDK
The Polkadot SDK is not merely an "integrated repository," but a standardized protocol stack that redefines the logic of chain building. Its core goal is to ensure that the construction, upgrading, cross-chain interaction, and governance of chains possess "system-level consistency," freeing developers from complex engineering configurations to focus on business and innovation.
This structure makes the Polkadot SDK not just a "chain-building framework," but more like an operating system that can continuously evolve.
As emphasized in the official documentation: the SDK not only provides modules but also defines how these modules can collaborate securely, share resources, and upgrade.
From Substrate to Polkadot SDK: Why EVM Enters the "Native Era" in Polkadot
Substrate itself does not come with EVM but dynamically integrates it through pallets and RPC modules in the Frontier repository. Any Substrate chain (such as Moonbeam, Astar, Acala, etc.) must import these modules.
Frontier nodes maintain additional data structures (Ethereum block hashes, transaction indexes, logs, etc.) to meet RPC indexing query functions, resulting in higher resource overhead compared to pure Substrate nodes.
Some developers refer to it as the "Ethereum sandbox in Substrate" because it simulates a complete EVM execution and storage model outside the Substrate environment.
However, this also brings some limitations:
User experience fragmentation: It requires a combination of Polkadot.js-like wallets and Metamask, with EVM/ERC20 and Substrate assets typically operating independently (some projects alleviate this through address mapping and custom front-end parts, but the essence remains unchanged).
High resource consumption: Nodes need to perform specialized indexing and block parsing for EVM-related RPC, adding new data and storage pressure (especially for ETH-style_block/explorer, etc.).
Isolation of EVM & Substrate modules: EVM contracts find it difficult to directly call or manipulate Substrate's native pallets, complicating logic reuse/permission management, and the "sandbox effect" is evident.
To break these limitations, Polkadot's parachain Moonbeam has made deeper integrations of EVM compatibility based on the existing Frontier. Moonbeam is not simply "plugging into Frontier"—it has undergone extensive rewrites and deep binding with Substrate, embedding EVM pallets, Ethereum pallets, account management, and XCM cross-chain consensus interfaces into the main Runtime, unifying the underlying Substrate with EVM assets, events, and governance distribution.
Moonbeam employs multiple mappings and bridge pallet designs to map EVM addresses to Substrate addresses, allowing accounts to smoothly transfer, manage assets, and call native pallets between the EVM and Substrate layers, significantly alleviating the user experience of "dual wallets" (although the private key formats differ, most support dual signatures and automatic recognition).
Moonbeam nodes simultaneously expose Ethereum JSON-RPC and Substrate RPC, enabling developers to interact with the same assets using Metamask/Hardhat/tools and Polkadot.js/app .
However, although Moonbeam has achieved the mapping bridge between EVM addresses and Substrate addresses, the underlying differences in user private key types and signature algorithms (Ethereum secp256k1 vs. Substrate sr25519/ed25519) mean that not all hardware wallets or ecosystem tools can "automatically support" dual-chain signatures, potentially causing compatibility barriers in extreme scenarios.
Some advanced operations (especially chain-native governance, proxy delegation, etc.) require specialized Substrate wallets, and the connected experience still lags behind pure EVM chains.
Cross-chain scenarios involving multiple assets and tokens (Native, ERC20, Substrate assets) still require management of different forms of addresses/IDs, approval logic, and mapping tables, leading to ongoing complexity in development and operations. Additionally, some inter-chain transfers rely on XCM or bridge protocol post-processing, which may result in synchronization delays.
While most EVM contracts can be upgraded through governance, the flexibility and permission control of upgrading Substrate runtimes are still not entirely equivalent, potentially leading to situations where the migration of certain assets and contract states requires chain-level coordination rather than pure EVM operations.
Disclaimer
The materials provided by PaperMoon and included in this article are for educational purposes only. They do not constitute financial or investment advice and should not be interpreted as guidance for any business decisions. We recommend that readers conduct independent research and consult professionals before making any investment or business-related decisions. PaperMoon assumes no responsibility for any actions taken based on the content of this article.
Read More
https://polkadot-evm.github.io/frontier/overview
https://github.com/polkadot-evm/frontier
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