Common vs Railgun: app simplicity or protocol scale (2026)

Common and Railgun both use zero-knowledge privacy, but they are different kinds of products. Common offers a web app centered on depositing into a shielder contract and withdrawing to a fresh, unlinkable wallet. It also describes TraceBreaker and shielded stablecoin support. Railgun is privacy infrastructure for transactions and contract interactions, including DeFi; it does not offer a first-party app, so you use it through a third-party wallet or front end.

The clearest practical distinction is scale. Common has about $1,672 in TVL, compared with about $113 million for Railgun. Common’s low TVL may mean a thinner anonymity set, while Railgun’s larger TVL indicates substantially more funds in the system. Neither figure alone guarantees that a particular transaction will be private.

Common is described as live on Arbitrum and Aleph Zero EVM, while its listed chain data names Arbitrum. Railgun is deployed on Ethereum, Arbitrum, BNB Chain and Polygon. That gives Railgun broader stated EVM coverage, including Ethereum, while both include Arbitrum.

Common’s main flow is to deposit into a shielder and withdraw to a new address. It says users can shield stablecoins such as USDT and USDC, with a yield option, and pay fees in the token being shielded rather than needing a native gas token. Railgun focuses on private transactions and smart-contract interactions, with an emphasis on DeFi use. It runs as smart contracts directly on supported networks and is described as having no bridge or layer-2. Choose based on whether you want Common’s guided shielding flow or Railgun’s broader infrastructure and network range.

Neither project publishes a fee schedule. Common says fees can be paid in the token being shielded, but that does not mean transactions are free. Network fees on Arbitrum or Aleph Zero EVM still apply, and charges related to shielding, withdrawing or yield should be checked in the app before confirming.

Railgun’s fees are also not published. Any protocol or shielding charges would need to be checked in the wallet or app used to access it, alongside network gas on the selected chain. For both projects, the exact cost may depend on the transaction and access method. Compare the final fee details in the relevant interface before moving funds; do not assume the fee-token option or a third-party integration removes network costs.

Both systems are non-custodial by their descriptions, so users keep control of their keys; lost access cannot be recovered by a central operator. That does not remove smart-contract or zero-knowledge system risks. Funds held in the contracts remain exposed to those risks.

Common says its apps were audited by Kudelski Security and zkSecurity, but the reports are not public, and DefiLlama lists zero audits. Railgun has two audits listed, but auditor names, dates and findings are not public. Treat the audit record for each as difficult to verify. Privacy also depends on behavior: reusing addresses or moving funds in obvious patterns can link activity, and Railgun notes that timing after shielding matters. Common’s small TVL may weaken its anonymity set. Privacy tools can face regulatory scrutiny, so check local rules before using either.

Choose Common if you want a direct web-app flow for depositing into a shielder and withdrawing to a fresh address, and you value the option to pay fees in the token you shield. Its stablecoin features may also matter if you want shielding with a yield option. The trade-offs are very low TVL, limited network coverage and audit reports that are not publicly available.

Choose Railgun if you want privacy infrastructure for DeFi interactions, need access across Ethereum, Arbitrum, BNB Chain and Polygon, or place more weight on its much larger TVL and multi-year record. You will need to find a suitable third-party wallet or front end, and the experience can vary by integration. Neither publishes fees or public audit details sufficient to compare scope and findings, so check costs and the available safety information before using either.