Union — open source GitHub project

Union is a zero-knowledge protocol for blockchain interoperability and cross-chain message transfer.

What it is

Union is a protocol for blockchain interoperability. Its goal is to help networks pass messages and state without relying only on one trusted bridge. The project description emphasizes zero-knowledge proofs, security, and decentralized finance use cases.

The unionlabs/union repository has been on GitHub since 2023. Its primary language is Rust, the license is Apache-2.0, and the official site is union.build. Topics include Cosmos, Ethereum, EVM, relayer, prover, CosmWasm, Solidity, Move, Svelte, and TypeScript, so this is a multilayer system rather than one contract.

What is inside

Inside are protocol components, prover and relayer code, indexers, web parts, integrations with blockchain ecosystems, and documentation. Projects like this are complex because they combine cryptography, network infrastructure, smart contracts, and node operation.

Component map

This fragment shows a logical map, not a launch command. For an interoperability protocol, the roles matter: who proves state, who relays messages, and where the result is verified.

Language: Plain text

Source chain -> prover -> relayer -> destination chain
              |                 |
              +-- proof data ----+

Components:
- clients and contracts
- prover services
- relayer services
- indexers and monitoring

Where it helps

Union belongs to infrastructure for applications that need to connect several networks: message transfer, asset movement, state synchronization, and cross-chain products. It is not a consumer wallet; it is a layer used by protocol and application developers.

Trust assumptions matter in these systems. A team needs to understand which proofs are verified, which parts run off-chain, who operates relayers, and what happens during failures.

Strengths and tradeoffs

The strength is a focus on cryptographically verifiable interoperability and support for multiple ecosystems. That matches the direction where blockchain applications try to rely less on centralized bridges.

The tradeoff is complexity and risk. Cross-chain protocols touch money, security, contract upgrades, and infrastructure operation. This catalog page is not investment advice; use requires audits, documentation, test networks, and economic risk analysis.