The archive · Money & Fintech · Product decision · 2022–2025
Union Labs bets ZK proofs beat trusted bridges; mainnet live Sept 2025
Union Labs built a zero-knowledge settlement layer for moving assets between blockchains; after $16M raised, its mainnet went live in September 2025.
Union Labs
What the business is
Union Labs builds Union, an open-source, zero-knowledge interoperability layer that lets blockchains (Ethereum, IBC/Cosmos, Bitcoin ecosystems) move assets and messages without trusting a third-party bridge operator.
Starting capital：$16M total: $4M seed led by Galileo (Anagram) in 2023, plus a $12M Series A led by Gumi Cryptos Capital and LongHash Ventures announced 2024-12-03.
How it started
Founder Karel Kubat and a team drawn from Consensys, Tokensoft, and Polygon Labs started Union in 2022 after watching bridge hacks and multi-sig failures make cross-chain transfers the industry's weakest link. Their pitch: prove consensus with zero-knowledge cryptography instead of trusting an operator.
What happened
The project raised a $4M seed (Galileo fund by Anagram), then a $12M Series A in December 2024 backed by founders of Polygon, Movement, and Berachain. It shipped an Ethereum-to-IBC bridge, ran a public ZK trusted setup, and opened its code on GitHub, where star growth made it ROSS Index's #1 open-source startup of 2025.
How it ended up
Union's public mainnet went live on 2025-09-03: validators producing blocks on union-1, the U token claimable in the U Drop, and a genesis staking vault live. The alpha phase had already moved $145M+ in assets.
Background
Union Labs started from a security observation: the fastest-growing part of crypto was also the most dangerous one. Cross-chain bridges relied on trusted operators, multi-signature wallets, and oracles, and every few months one of them got hacked. Founder Karel Kubat's bet was that zero-knowledge proofs could replace that trust with mathematics — a light-client, ZK-verified settlement layer between any two chains.
The company raised $4M in seed (Galileo by Anagram) and $12M in Series A (Gumi Cryptos Capital and LongHash Ventures) by December 2024, and shipped the flagship Ethereum-to-IBC bridge plus Bitcoin ecosystem work. All code was open-sourced, which turned the repo into a developer phenomenon: ROSS Index ranked unionlabs/union the #1 fastest-growing open-source startup of 2025 with 74.3K stars and 54.2x growth.
The bet reached its payoff moment on 2025-09-03, when Union's public mainnet went live with validators producing blocks on union-1, the U token distributed via U Drop, and a genesis staking vault. During alpha, more than $145M of assets had already moved across Union routes — evidence that the trustless model worked before the official launch.
What has to be true
- Bridge hacks made 'trustless' a measurable product advantage, not just a slogan, so the ZK design had an obvious buyer.
- Open-sourcing the code let developers audit the security claims, which is how the repo earned 74K stars and ROSS's #1 growth rank.
- Starting with Ethereum-to-IBC gave Union a concrete first corridor instead of promising to connect every chain at once.
- A token (U) aligned validators, stakers, and users with the network's success from day one of mainnet.
What can be applied
When an industry's weakest link is trust, a startup can win by making the failure mode provably impossible — but only if it can reach mainnet before the money and the attention move on.
Aftermath
As of 2026-09-02 Union is live but early: mainnet launched 2025-09-03, U token claiming and pre-staking are open, the genesis staking vault will open publicly alongside Escher's liquid-staked eU, and the uname crosschain identity system is in registration. The roadmap calls for more connected chains, with years of planned milestones per the launch post.
Sources
- Union Raises $12M in Series A to Fight Fragmentation Across EVM and Non-EVM Chains
- Union Mainnet is Live
- Union Blockchain Officially Launches Mainnet, U Tokens Now Claimable
- Top trending open-source startups in 2025 (Annual ROSS Index)
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