At ZetaChain, our mission is to build the Universal Blockchain that makes using Web3 as simple and unified as the Internet for both humans and AI.

Interoperability remains one of the hardest technical challenges in blockchain.

As ecosystems multiply, developers are no longer debating if chains should communicate but how to connect them securely and efficiently.

Two leading projects, ZetaChain and Axelar, take fundamentally different approaches to this problem.

ZetaChain is a Proof-of-Stake Layer 1 blockchain that natively embeds interoperability into its consensus and smart-contract layer, while Axelar operates as a cross-chain messaging and token routing network.

This article compares both architectures through the lens of developers building scalable, trust-minimized, and truly omnichain applications.

High-Level Overview

ZetaChain in Brief

ZetaChain is a Layer 1 blockchain built on the Cosmos SDK and CometBFT consensus engine.

It connects multiple blockchains—including EVM chains (Ethereum, BSC, Polygon, Avalanche), non-EVM chains (Solana, Sui, TON), and non-smart-contract chains like Bitcoin and Dogecoin—through validator-level observation and signing.

Key components:

• Core Validators:

  Participate in PoS consensus and execute on-chain transactions.

• Observer-Signer Validators:

  Monitor external chains and collectively sign outbound transactions using Threshold Signature Schemes (TSS).

• ZetaChain EVM:

  A built-in Ethereum-compatible environment running Universal Smart Contracts that can execute logic across any connected chain.

ZetaChain is itself the execution layer where cross-chain logic runs natively within the blockchain's consensus.

Axelar in Brief

Axelar is a decentralized PoS network built on the Cosmos SDK that connects 70+ blockchains through General Message Passing (GMP) and Interchain Token Service (ITS).

Core components:

• Validator Network:

  Observes connected blockchains, verifies messages, and reaches BFT consensus on Axelar's own Layer 1 chain.

• Gateways:

  Smart contracts (or equivalents) on each connected chain that verify Axelar’s

  threshold signature

  and then execute the approved command (e.g., mint/burn interchain tokens, call target contracts).

• Relayers:

  Optional agents that deliver verified messages from Axelar to destination chains.

• Gas Service:

  Allows users to prepay and, if needed, increase destination gas to ensure execution.

Applications use:

• GMP for arbitrary data and function calls between chains.

• ITS (or legacy wrapped assets via the Gateway) for cross-chain token transfers.

Unlike ZetaChain’s native execution model, Axelar primarily acts as an interoperability middleware layer: it routes and authorizes cross-chain messages, while application logic runs on the connected source/destination chains.

Architectural Comparison

📘 Learn more: ZetaChain Architecture Overview

Trust and Security Assumptions

ZetaChain — Validator Consensus + TSS

ZetaChain validators reach on-chain BFT consensus over cross-chain events.

When an external-chain event (such as a Bitcoin deposit) is observed, two-thirds of validators must agree before executing any on-chain action.

For outbound transactions, ZetaChain uses Threshold Signature Schemes (TSS):

• Validators co-sign transactions, ensuring no single node controls a private key.

• Validators directly manage addresses on external chains such as Bitcoin and Ethereum.

• Validators are staked and subject to slashing, aligning economic security with network integrity.

Axelar — Validator Verification Network

Axelar uses a decentralized PoS validator set that verifies messages and finalizes them through its own blockchain consensus.

Validators sign attestations that are verified by Gateway contracts on destination chains before executing the corresponding transactions.

Security features:

• Interchain Amplifier :

  Establishes security standards and auditing for verifiers and relayers.

• Bonded validators & slashing:

  standard Cosmos slashing for downtime/double-sign.

• On-chain governance:

  validators/AXL stakers govern upgrades/params; some fast-path items via governed multisig.

Token and Asset Models

ZetaChain ZRC-20

ZetaChain introduces ZRC-20 tokens—protocol-managed representations of assets held collectively by validators.

They function similarly to wrapped assets but are managed and verified directly by ZetaChain's consensus, not by external bridges.

Cross-Chain Programmability

ZetaChain — Universal Smart Contracts

Developers deploy a single Universal Smart Contract on ZetaChain's EVM.

That contract can:

• Accept inbound calls or token deposits from any connected chain.

• Execute complex logic atomically.

• Send outbound transactions to other chains through validators.

If a transaction fails, ZetaChain automatically reverts and refunds users.

This single-deployment model delivers truly omnichain composability without manual message reconciliation.

📘 Docs: Universal Apps Guide

Axelar — General Message Passing (GMP)

Developers deploy contracts on each chain they wish to connect.

Messages are sent via GMP, routed through the Axelar network, and executed on the destination chain once validated by its Gateway.

Pros:

• Flexible, supports arbitrary function calls.

• Broad EVM and Cosmos coverage.

Cons:

• Requires multiple deployments and asynchronous coordination.

• State is split across chains and must be manually synchronized.

• Each transaction consumes gas on both chains.

Bitcoin and Non-EVM Chain Support

ZetaChain

ZetaChain directly connects to EVM and non-EVM chains, including Bitcoin at the protocol level.

Validators observe BTC transactions natively, trigger ZetaChain smart contracts, and sign outbound BTC transfers using TSS.

This enables Bitcoin-native DeFi and omnichain apps without requiring intermediary layers or wrapped tokens managed by external protocols.

Architecture: ZetaChain validators run Bitcoin full nodes and use TSS to directly control Bitcoin addresses, enabling native Bitcoin programmability without bridges or wrappers.

📘 Docs: Bitcoin Developer Docs

Axelar

Axelar primarily supports programmable smart-contract ecosystems such as EVM, Cosmos, and Move-based chains.

Bitcoin Integration: Axelar has integrated Bitcoin support through partnerships with Babylon Genesis (enabling Bitcoin staking across 70+ chains) and via Stacks bridges. However, this approach relies on intermediary smart contract layers rather than direct Bitcoin protocol interaction. Axelar's Interchain Amplifier allows developers to connect Bitcoin-adjacent networks, but the integration architecture differs fundamentally from direct Bitcoin observation and signing.

Gas and Fees

ZetaChain abstracts gas through ZRC-20 tokens, simplifying multi-chain interactions with a unified fee model.

Axelar's Gas Service lets users prepay for destination-chain execution and increase gas if necessary.

Developer Experience

ZetaChain simplifies development with a single, unified EVM and built-in omnichain APIs.

Axelar offers a mature SDK stack for EVM and Cosmos chains.

Comparative Summary

Conclusion

ZetaChain embeds interoperability at the protocol level with native Bitcoin support via TSS, enabling developers to deploy once and orchestrate across all chains atomically.

Axelar provides mature cross-chain messaging across 70+ blockchains but requires multi-chain deployments and intermediary layers for Bitcoin.

For developers building omnichain applications, ZetaChain's unified execution model offers superior simplicity, composability, and native cross-chain access.

About ZetaChain

ZetaChain is the first Universal Blockchain with native access to Bitcoin, Ethereum, Solana, and more, offering seamless user experience and unified liquidity to the next billions of users. With its Universal EVM, ZetaChain empowers developers to build Universal Apps that operate natively across any blockchain, creating a fluid crypto ecosystem from a single platform.

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