Polkadot unites blockchains and brings an end to the era of siloed networks. With XCM, Polkadot enables secure cross-chain exchange of any type of data, unlocking new products and services that have never been seen before.
For blockchains to work together and form the basis of Web3, they need a common language for communication. Polkadot sets the standard with XCM, a powerful format for secure messaging across Polkadot-native blockchains (called parachains) and with external networks via bridges.
XCM is a language for building innovative new cross-chain applications and services. Giving applications the ability to span multiple blockchains allows them to leverage the key features and strengths of each for new interoperable use cases.
Hoon Kim
This is huge - the possibilities are endless! When we have XCM, we have a stable and reliable interchain messaging channel that is far superior to the fragmented bridges. I can imagine a future where more and more projects use XCM to create something that was impossible just a couple of years ago.
0+ ProjectsPolkadot has one of the most active developer communities in blockchain. XCM connects a growing ecosystem of 450+ projects building the next generation of blockchain apps and services and pioneering the world of Web3.
Dominik Harz
XCM is the heart of the Polkadot ecosystem. For Interlay, it`s the main reason we built on Polkadot: a way for us to seamlessly integrate with other applications out of the box, instead of spending months/years per custom bridge.
XCM is the next great leap for cross-chain technology, offering several improvements over previous bridging solutions:
Supports rich data
Previous cross-chain technologies mostly involved moving tokens from one chain to another. XCM messages can contain any type of data, enabling not just cross-chain token transfers but feature-rich cross-chain applications. This will lead to innovative new services not possible on legacy networks.
Programmable
Much more than messages in the conventional sense, XCM messages are actually computer programs sent from one place and executed in another. This enables a level of cross-chain programmability never before seen in blockchain technology: with XCM, different blockchains can now program each other.
Secure & trustless
Before XCM, blockchains could only communicate via bridges that relied on trusted third parties, creating a ‘weakest link’ problem and leading to several infamous hacks. On Polkadot, messages between parachains share the same high security as the entire network, and do not require funds to be deposited with centralized and vulnerable third-party custodians.
Cross-consensus
XCM works not just between different blockchains but also between smart contracts on different virtual machines, between Substrate pallets, and over bridges. It can even connect networks built on different consensus mechanisms. For example, XCM could be used to communicate between a proof-of-work network like Bitcoin and a proof-of-stake network like Polkadot.
Lucas Vogelsang
XCM brings the true power of Polkadot to light and delivers on the vision of a scalable multichain future; the different parachains on Polkadot are now able to collaborate and assets can move around quickly without taking on any security risks that come from bridges.
XCM provides instructions for how to compose, send, and interpret cross-chain messages. Once received, the instructions contained in XCM messages are executed by the destination chain.
DestinationBetween parachains
Messages between parachains are sent via XCMP channels (currently live as XCMP-Lite aka HRMP)
Parachain - Relay Chain
Messages between the Relay Chain and a single parachain are sent via VMP channels
Over bridges
Messages between Polkadot and external blockchain networks, or between two solo chains outside the Polkadot network, are sent over bridges
Eliott Teissonniere
XCM will allow us to leverage the unique features from our parachain partners in the most secure manner possible, without having to reinvent the wheel. For instance, we will be able to run a DAO on Astar that manages funds on Acala and controls real-world devices via Nodle.
On single isolated blockchains, messages are sent and executed synchronously (in a single instant). This works well for many things, but rules out functionality that requires freedom from time constraints, such as on-chain scheduling. Cross-chain XCM messages are asynchronous, allowing developers to trigger functions across several chains to take place variably over time.
Learn more about how XCM works in the Polkadot Wiki. Ready to start building? Get in touch for hands-on guidance and support.