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Cross-Chain Messaging (XCM)

Communication protocol between blockchains in the Polkadot ecosystem

What is Cross-Chain Messaging (XCM)?

Polkadot's cross-chain communication format that enables parachains to send messages, tokens, and arbitrary data to each other securely. XCM is what makes Polkadot more than a collection of isolated chains — it's the language they speak to coordinate actions, transfer assets, and compose functionality across boundaries. True interoperability isn't just connecting chains, it's letting them meaningfully interact.

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In plain words

"The postal service between blockchains — a standardized message format that lets chains send instructions, assets, and data to each other."

How it works

Key takeaways

  • Cross-chain message format, not a bridge

  • Supports assets, data, and instructions

  • Native to Polkadot's architecture

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Real-world example

You send DOT from the Relay Chain to Acala using XCM. Acala receives the message, mints a local DOT representation, and credits your account — all trustless.

Related terms

Interoperability

Blockchains talking to each other

Parachain

Application-specific blockchain connected to Polkadot

Relay Chain

The security and coordination layer of Polkadot

Polkadot (DOT)

Multi-chain protocol for blockchain interoperability

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