This bridge needs a hero

Bridging works like quantum teleportation: the coin does not physically move anywhere — it is locked in the source network, and an equivalent amount appears in the destination network. But for this to happen, both sides must be perfectly synchronized. This is where messaging comes into play, through which the bridge informs the destination network of what happened in the source network.

Without this invisible layer, teleportation would not work — the asset could be lost or duplicated. It is the transmission of the message that allows two completely independent smart contracts on different blockchains to behave as part of a single system.

The Allbridge team explains how messaging works and why decentralized bridging is impossible without it.

What is messaging and how does it work?

Messaging is the process of transmitting information ( but not tokens ) from one blockchain to another. Example of operation:

1. The user initiates a transfer in the source network.
2. The smart contract accepts tokens and creates a message - a compact set of data containing information about the transfer amount, destination network, recipient address, and token.

This message cannot be simply forwarded — it needs to be confirmed before the destination network can trust it.

Finality and validators

The role of message confirmation is performed by validators (sometimes they are referred to as guardians or oracles, the exact term depends on the protocol). Before processing the message in the destination network, the transaction must be recognized as finalized — that is, one that cannot be canceled or changed as a result of a blockchain rollback.

In different networks, the criteria differ, and the messaging protocol must take this into account. In the destination network, a group of validators confirms the transaction and cryptographically signs the message.

Relay

Another link in the work of the bridge — the relayer — sends a signed message to the smart contract of the destination network, which checks the signatures of the validators. If everything is correct, the message is accepted and executed. The relayer pays the gas and receives a small fee as compensation, which the user sees when making the transfer.

What is contained in the message?

A message is simply a structured set of bytes. The sending contract encodes it, and the receiving contract decodes it. It contains only the necessary information about the task in the target network. Bridges optimize the handling of messages, reducing costs and increasing efficiency.

How Allbridge Core Makes Messaging Smarter

Message transmission between blockchains is a powerful tool, but not cheap. Every byte stored or verified on the blockchain requires gas. For a speed-oriented bridge, scalability and efficiency are important.

Problem: large messages

A typical message contains:

• transfer amount;
• token address;
• recipient address;
• ID of the source and target networks;
• unique nonce.

In its original form, the information can take up more than 100 bytes, making each transaction expensive.

Solution: hashed messages

Instead of storing the full message, Allbridge Core transforms it into a 32-byte hash — a unique and verifiable "fingerprint." In it, the first two bytes are replaced with the IDs of the source and target networks. This allows for direction verification directly from the hash without full decoding: a small technical change results in a significant gas savings.

Compromise

Hashing reduces the cost of storing messages. Since the destination network only sees the hash, the relayer is obliged to provide the original message so that the smart contract can recalculate and verify the data. This makes working with the blockchain cheaper but increases the load on the relayer.

The advantage of flexibility

Most solutions are tightly bound to a specific messaging protocol. This can be a limitation, especially if different blockchains support different messaging protocols. A bridge that is not dependent on a specific protocol can operate with multiple at the same time.

Advantages:

• support for more blockchains;
• resilience — in the event of a failure of one protocol, another can be used;
• flexibility — easily add support for new protocols without rewriting the system.

Conclusion: the value of messaging

The goal of messaging is to allow blockchains to "communicate" and make cross-chain coordination decentralized. Smart contracts in different networks exchange information without needing to know anything about each other — the only important fact is that a verified message has arrived. This is what turns isolated blockchains into parts of a single system — without compromising decentralization.

But the main thing is the internal architecture that allows the transfer of information about transfers between blockchains, leaving critical logic to smart contracts.