Frequently asked questions

Questions that apply everywhere you use Sigma9 — the browser extension today, and future apps as they ship. Looking for something specific? Browser extension → · Monad → · Solana / Kora →

What is a gasless USDC wallet?

A gasless USDC wallet lets you hold only USDC — the network fee itself is paid in USDC, so you never need to buy or hold a separate native gas token like ETH or SOL just to move your money. See how gasless works →

Which networks are supported?

Ethereum, Arbitrum, Base, Optimism, Polygon, Unichain, Monad, World Chain and Solana mainnet.

Can I move any token to any network?

Not always, and that's on purpose. Every supported network can send and receive gaslessly, but moving a token between two different networks (bridging) only works where a real cross-chain route exists for that token today. On some networks, a token can currently only move within that same network — sending it elsewhere isn't available yet. Sigma9 only ever offers a route that actually works, so you never end up stuck with money you can't move.

What's USDT0, and is it different from USDT?

USDT0 is Tether's own official "omnichain" version of USDT. It moves natively across many blockchains using a cross-chain standard called LayerZero, instead of relying on a wrapped or separately-bridged copy — and it's always worth exactly one USDT, 1:1, no exceptions. Ethereum still holds the original, canonical USDT that everything else is anchored to.

Sigma9 simply shows whichever version a given network actually uses — classic USDT on some chains, USDT0 on others. Either way it's the same dollar: send, receive, and check your balance exactly as you always would. If you ever see "USDT0" in the app, there's nothing to worry about — it isn't a different or lesser token, just Tether's name for USDT on that network. And as above, on a few of those networks USDT can currently only be sent within that same network, not bridged elsewhere yet.

Is Sigma9 self-custody?

Yes. Your keys are encrypted locally on your device and decrypted only in memory to sign a transaction — they are never sent to a server. Sigma9 has no analytics or tracking.

Can a malicious website drain my Sigma9 wallet?

No. Sigma9 does not connect to dApps or inject a wallet provider into web pages, and it never asks you to sign an unknown smart-contract transaction or grant a token approval. It only sends, receives and bridges the assets it supports, so the common connect-wallet-and-drain-it attack has no way in.

Is there a sign-up or account?

No. Sigma9 is self-custody — it's yours. Your keys stay on your device, and nothing is stored on a server.

Want more detail? How gasless USDC works → · Gasless USDC on Monad → · Kora relayer for gasless Solana →

Sigma9 — gasless USDC only. Keys stay on your device.