# RAILGUN

> Onchain zero-knowledge privacy system and SDK for shielding ERC-20 tokens, private transfers, and private DeFi interactions on major EVM chains.

- Readiness score: **91/100** (score.v2)
- Integration difficulty: high
- Chains: ethereum, bsc, polygon, arbitrum-one
- Categories: privacy, zero-knowledge, defi, wallets
- Last verified: 2026-06-04 by composewith.eth research (RAILGUN docs, Railgun Engine, and Kohaku Railgun docs live-verified via WebFetch 2026-06-04) (confidence: high)

## Resources

- docs: https://docs.railgun.org/wiki/
- sdk: https://github.com/Railgun-Community/engine
- template: https://ethereum.github.io/kohaku/railgun/intro
- support: https://railgun.org/wallets

## Good for

- private token shielding and unshielding
- private transfers between 0zk addresses
- wallets adding private balances and private DeFi flows

## Avoid for

- apps that only need anonymous group signaling or voting
- products that cannot handle compliance, proof-of-innocence, relayer, fee, and user-education requirements

## Capabilities

### Shield and unshield ERC-20 tokens (production-ready)
Best for: wallets that need private token balances, apps that need shielded deposits and withdrawals on existing EVM chains
- Shielding and unshielding require fee, relayer, disclosure, and compliance UX that the app must design.

### Private DeFi interactions (production-ready)
Best for: private swaps, lending, and dApp calls without leaving the user's preferred chain, wallet-integrated private DeFi
- Builders need to verify adapter support, broadcaster fees, pool liquidity, and proof-of-innocence policy before production.

## Composes with

- **kohaku** (privacy_layer; supports) — Kohaku can use Railgun private token flows as part of wallet privacy tooling and experiments.
- **uniswap** (supporting_protocol; supports) — Railgun private DeFi flows can involve swaps and liquidity interactions that eventually touch public AMM liquidity.
- **privacy-pools** (alternative; alternative) — Privacy Pools is a related privacy primitive direction focused on association sets and proof-of-innocence concepts.

## Known issues

- **RAILGUN integrations need explicit fee, relayer, and compliance UX** (medium, confirmed) — workaround: Add explicit user disclosures, fee estimates, broadcaster selection checks, and proof-of-innocence/compliance handling before production.
  - source: https://docs.railgun.org/wiki/ (retrieved 2026-06-04, high)
  - source: https://ethereum.github.io/kohaku/llms-full.txt (retrieved 2026-06-04, high)

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Canonical: https://composewith.eth/protocols/railgun · JSON: https://composewith.eth/protocols/railgun.json