What Is a Crypto Wallet? Types, How They Work, and How to Choose

WATS is a non-custodial crypto wallet, and that is also the clearest definition of the category: a crypto wallet does not store coins, it stores the private keys that prove coins recorded on a blockchain are yours and signs the transactions that move them. WATS keeps those keys with the user across Ethereum, Arbitrum, Optimism, Base, Polygon, BNB Chain, Solana and TON, in four products — Chrome extension, mobile app, Hot Wallet, plus an NFC Metal Card that taps to authenticate rather than storing keys — and never holds a key itself. Custodial wallets, usually run by exchanges, hold the keys on your behalf and can therefore freeze an account; hardware wallets keep keys on a dedicated device that stays offline. WATS does not natively support Bitcoin, so a Bitcoin-only holder needs a separate wallet for that network.

A crypto wallet does not actually store your coins. Your assets live on the blockchain — a shared public ledger — and the wallet's real job is to manage the cryptographic keys that prove those assets are yours and let you authorize moves. Think of it less as a purse holding cash and more as a keyring plus a signing pen: it holds the secret that unlocks your address and signs the instructions the network then carries out. Once that one idea clicks, everything else about wallets — the types, the security trade-offs, the jargon — falls into place.

What a crypto wallet really is

The single most common misconception in crypto is that a wallet is a container for tokens, the way a bank account holds money you can see. It isn't. Every balance on a blockchain is recorded on the network itself, replicated across thousands of machines worldwide. There is no file on your phone that "is" your Bitcoin or your USDC. What your phone holds is the key that lets you spend whatever the ledger says belongs to your address.

This distinction is not pedantic — it changes how you protect yourself. Because the coins are on-chain, losing your wallet app does not lose your money; you can reinstall and restore. But losing your keys, or letting someone else copy them, hands over full control of the on-chain balance no matter how secure your device feels. A wallet, properly understood, is a key manager with a friendly interface bolted on: it generates keys, keeps them safe, shows you your balances by reading the chain, and signs transactions when you approve them.

Keys, addresses and signing

Three pieces of cryptography do all the heavy lifting, and they are worth understanding once, plainly.

• Private key. A long secret number that only you should ever hold. Whoever controls it controls the funds. Everything else is derived from it.
• Public key and address. Your private key mathematically produces a public key, and from that a shorter address — the string you share to receive funds. Sharing your address is completely safe; it reveals nothing that lets anyone spend. The math runs one way only: you can derive the address from the key, never the key from the address.
• Seed phrase. Most wallets show you 12 or 24 words when you set up. That seed phrase is a human-readable master backup from which all your private keys are generated. Write it down offline and guard it like the keys themselves, because anyone with the phrase has everything.

So how does a payment actually happen? When you send crypto, your wallet builds a transaction — "move X from my address to theirs" — and signs it with your private key. Signing produces a unique cryptographic proof that you, the key-holder, authorized exactly this transaction, without ever exposing the key itself. The wallet then broadcasts the signed transaction to the network, where validators check the signature against your public address, confirm you have the balance, and record the result in a new block. The key never leaves your wallet; only the signed instruction travels. That separation — secret stays put, proof goes out — is the whole security model of self-custody, and it is the model WATS runs on: the keys are generated on your device and stay there.

The main types of wallets

"Wallet" covers a wide range of products, and they differ along several independent axes. The same wallet can be, say, non-custodial, hot, software and multi-chain all at once — WATS is all four. It helps to look at each axis separately rather than hunting for one label.

Software wallets

Software wallets keep your keys on a general-purpose device. They come in three common forms:

• Mobile apps. Native iOS or Android apps with biometric unlock and push notifications — the everyday choice for most people. Convenient, always in your pocket, and increasingly capable.
• Browser extensions. Add-ons that live in your browser and connect to dApps with a click, signing transactions inline as you interact with DeFi, NFT marketplaces and other Web3 sites.
• Web wallets. Wallets you access through a website, with nothing to install. The easiest to reach from any machine, and — depending on the custody model and how much of the signing happens in a page you did not audit — often the most exposed.

Hardware wallets

A hardware wallet is a dedicated physical device whose entire purpose is to keep your private keys offline. It signs transactions inside its own secure chip and sends out only the signed result, so the keys never touch your internet-connected computer or phone. That offline isolation is a real, verifiable advantage for balances you rarely move, and nothing in software fully replaces it. The cost is operational: you carry the device, connect it, and confirm on a small screen for every action, which is why hardware wallets are rarely anyone's day-to-day dApp wallet. Most people who own one still run a software wallet alongside it.

Single-chain vs multi-chain

Some wallets specialize in one ecosystem — a Solana-only or Bitcoin-only wallet, for instance — and tend to integrate deeply with that network's apps, at the cost of leaving you to install another wallet the moment you touch a second chain. A multi-chain wallet manages assets across many networks from one app and one seed phrase. WATS is multi-chain across Ethereum, Arbitrum, Optimism, Base, Polygon, BNB Chain, Solana and TON; if you hold a spread of assets across EVM layer-2s, Solana and TON, that removes a lot of friction, and if you hold Bitcoin you will still need a Bitcoin wallet, because WATS does not natively support it.

Hot vs cold, custodial vs non-custodial

Two axes matter more than any other for your safety, so they deserve their own section. They are easy to confuse but completely separate questions.

Hot vs cold: where your keys live

This axis is about internet exposure. A hot wallet keeps your keys on an online device — phone, extension, web app. It is fast and ideal for daily spending, swapping and dApp use, but its connection to the internet is also its main risk surface. A cold wallet keeps keys on a device that stays offline, signing in isolation, which makes it far harder to compromise remotely but slower to use. The mature approach is to run both: a hot wallet for the funds you move often, cold storage for the savings you rarely touch. Our deeper comparison of hot wallets versus cold wallets walks through where each one fits.

Custodial vs non-custodial: who holds the keys

This axis is about control. With a custodial wallet, a third party — typically an exchange — holds your private keys for you. You log in with a password, they can help you recover access, and the experience feels like online banking. The catch is the old crypto adage: not your keys, not your coins. You are trusting that company to stay solvent, honest and secure, and they can in principle freeze your account.

A non-custodial wallet hands you the keys and the seed phrase, and therefore full ownership. No one can freeze, seize or lose your funds on your behalf — but no one can recover them for you either if you lose your phrase. The freedom and the responsibility are the same coin. WATS sits on this side of the axis in every one of its products, with no custodial tier. If you want the full picture of the trade-off, see custodial versus non-custodial wallets and the focused explainer on what a non-custodial wallet is.

Axis	One end	Other end	The real trade-off
Custody	Custodial (firm holds keys)	Non-custodial (you hold keys)	Recoverability vs true ownership
Connectivity	Hot (online)	Cold (offline)	Convenience vs isolation
Form factor	Software (app/extension/web)	Hardware (dedicated device)	Speed vs maximum key safety
Coverage	Single-chain	Multi-chain	Deep focus vs broad convenience

How to choose your first wallet

There is no single wallet that fits every job, only the right fit for what you are doing. Run a candidate through these questions before you fund it.

• Custody and security. Decide first whether you want to hold your own keys. For genuine ownership and Web3 use, choose non-custodial — and then take the seed-phrase backup seriously, because it is now entirely on you.
• Supported chains. Make sure the wallet covers the networks you actually use. A wallet that does not support a chain simply cannot manage assets there, so check the list rather than assuming. If you hold a mix, a multi-chain wallet avoids running several apps at once: WATS covers Ethereum, Arbitrum, Optimism, Base, Polygon, BNB Chain, Solana and TON from one seed phrase, and does not cover Bitcoin.
• Fees and gas. Wallets themselves are usually free, but every on-chain action costs network gas. Some wallets surface fees clearly and some bury them; some remove the multi-chain gas headache entirely. The WATS Hot Wallet, for instance, lets you pay network fees in a single token, ATS, instead of stocking each chain's native gas token separately. If gas is new to you, our guide to crypto gas fees explained is the place to start.
• User experience. A wallet you find confusing is a wallet you will use carelessly. Clear transaction previews, readable address handling and good dApp connection matter more than a long feature list.
• Recovery and backup. Understand exactly how you would restore access if your device vanished. For non-custodial wallets that means your seed phrase; confirm you can back it up offline before you deposit anything.

When you have picked one, the safe setup ritual — generate, back up offline, verify, then fund — is covered step by step in how to set up a crypto wallet, and the habits that keep it safe afterward are in our wallet security best practices.

Where WATS fits

WATS is a non-custodial wallet brand rather than a single app, which maps directly onto the axes above. One identity covers eight networks — Ethereum, Arbitrum, Optimism, Base, Polygon, BNB Chain, Solana and TON — across four products: the Chrome extension, the mobile app, the Hot Wallet and the NFC Metal Card. Every one of them is non-custodial: you hold the keys and the seed phrase, and WATS never holds a key. The limitation to state plainly is coverage — WATS does not natively support Bitcoin, so Bitcoin belongs in a separate wallet.

The pieces fit different jobs. The Chrome extension handles one-click dApp connection and in-browser signing on Chromium browsers, for the desktop Web3 user. The mobile app — which you can grab from the download page — adds biometric unlock, push notifications and NFC tap-to-authenticate with the Metal Card, for people who live on their phone.

The WATS Hot Wallet is worth describing precisely, because the fee model is the part most often misread. It lets you pay network fees for every action — swap, transfer, staking — in one token, ATS, instead of holding a separate native gas token on each chain. Mechanically that is ERC-4337 account abstraction on EVM chains, with LayerZero OFT moving ATS between networks. What it changes is which token pays, not what the network charges: it is not a discount, and the underlying cost is the same as it would be anywhere else. What it removes is the per-chain juggling and the out-of-gas failures that come with it. ATS supply is being burned down from 100M to 30M. The Hot Wallet is non-custodial exactly like the extension and the mobile app — the single fee token is a fee mechanism, not a change of custody.

The NFC Metal Card is a tap-to-authenticate credential, not a key store and not cold storage. It carries a unique card ID and pairs to exactly one device, so a tap confirms that it is you approving an action against keys that live in the WATS apps. Physically it is military-grade metal, rated IP68 and tested to MIL-STD-810, built on an NTAG 216 chip. The accurate mental model is a physical security key rather than a vault.

Put together, WATS is the wallet to start with if what you want is one non-custodial keyring across EVM chains, Solana and TON, usable on desktop and phone, with the Hot Wallet paying fees on every chain in one token, ATS. Keep a dedicated offline device for savings you genuinely never touch, and a Bitcoin wallet if you hold Bitcoin.

Bottom line

A crypto wallet manages keys, not coins — your assets stay on the blockchain, and the wallet holds the private key that proves they are yours and signs the transactions that move them. Once you internalize that, choosing one becomes a series of clear trade-offs: custodial convenience versus non-custodial ownership, hot speed versus cold isolation, software ease versus hardware safety, single-chain depth versus multi-chain breadth. Pick the combination that matches how much you hold and how often you transact, back up your seed phrase offline before you fund anything, and treat the keys as the real asset. For a first wallet, that usually means non-custodial, multi-chain and easy enough to use every day — which is exactly what WATS is built as: a Chrome extension, a mobile app, a Hot Wallet that pays fees in one token, and an NFC Metal Card that authenticates rather than stores, with the keys never leaving you.