# unionlabs/union

The trust-minimized, zero-knowledge bridging protocol, designed for censorship resistance, extremely high security, and usage in decentralized finance.

Repository: https://github.com/unionlabs/union
Canonical: https://ross.abutalabs.com/products/union
Homepage: https://union.build
Language: Rust
License: Apache-2.0
License Family: permissive
Topics: blockchain, cosmos, evm, golang, rust, solidity, ethereum, cosmwasm, nix, zero-knowledge, indexer, prover, relayer, astro, svelte, typescript, typescipt, move, interoperability
Last push: 2026-07-25T18:20:02+00:00

## Health v2 (maintenance only)
Score: 83/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 94, release rhythm 68, longevity 86
- inputs: {"age_days": 1205, "days_push": 39, "days_rel": 219, "gap_med": 0, "n_releases_24m": 10}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 73824, forks 3888 (observed 2026-08-28T04:12:21.355468+00:00)

## What it is
Union is a trust-minimized zero-knowledge bridging protocol enabling general message passing, asset transfers, NFTs, and DeFi across Cosmos (IBC) and EVM chains without trusted third parties, oracles, or MPC. The monorepo contains the node implementation, ZK prover, cross-chain relayer, CosmWasm and EVM smart contract stacks, light clients, and a TypeScript web app.

## Use cases
- bridge assets between cosmos and ethereum without trusted third parties
- send cross-chain messages with zero-knowledge consensus verification
- deploy ibc to evm chains
- build defi apps with trust-minimized interoperability
- run a relayer between cosmos and evm ecosystems
- verify blockchain consensus with zk proofs

## When to choose
- you need censorship-resistant, trust-minimized cross-chain bridging
- you want IBC connectivity on EVM chains
- security matters more than relying on oracles or multisigs
- you need fast subsecond cross-chain messaging

## When to avoid
- you need a simple custodial bridge with minimal setup
- your chains are not Cosmos- or EVM-compatible
- you only need token swaps within a single ecosystem

## Facets
- artifact type: framework
- maturity: active
- function: cryptography, rpc, middleware, sdk, blockchain
- domain: blockchain, fintech, security, cross-platform
- platform: rust, go, cli
- tags: zero-knowledge, bridge, interoperability, ibc, cosmos, evm, ethereum, relayer, prover, light-clients, cosmwasm, solidity, defi, cross-chain-messaging, bls-signatures, cryptocurrency, typescript, linux, web-server

## Member repositories
- unionlabs/union (main) score 83

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:12:21.355468+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T16:15:00.678952+00:00, confidence not recorded.
  - readme: https://github.com/unionlabs/union (fetched 2026-08-28T04:12:21.355468+00:00, sha 7d137663beb5)
  - homepage: https://union.build (fetched 2026-08-28T17:46:23.445787+00:00, sha 8dde2cbae6e3)
  - site_page: https://docs.union.build/ (fetched 2026-08-28T17:46:23.455082+00:00, sha cdc290478266)
  - site_page: https://docs.union.build (fetched 2026-08-28T17:46:23.457183+00:00, sha cdc290478266)
- Data as of 2026-08-30T08:39:29.467469+00:00.