How to use a Web3 wallet for authorization

Authorization through a Web3 wallet is a login to the service without a password, where you confirm ownership of the address with a cryptographic signature. The site requests a signature of a specially crafted message, the wallet shows you the text and domain, you sign - and you get a session. Passwords, confirmation e-mail and SMS are not needed, and phishing risks are reduced if implemented correctly. Below is how it works and how to use it safely.

1) Why log in with a wallet instead of a password

No passwords or leaks. Access is tied to your key, not to the service's password database.

A single "digital business card." Single address/name (ENS/UNS/NFD, etc.) for multiple applications.

Multichain and tolerability. Log in from any device that has your wallet (or seed on the hardware).

Privacy. You choose which data to disclose; by default - only address/signature (if the service does not ask for more).

2) How it works under the bonnet (short)

1. Wallet connection. Through a browser extension (MetaMask/Rabby, etc.) or WalletConnect (QR code).

2. Signature Request (SIWE/EIP-4361). The site forms a human-readable message: domain, your address, goal (login), nonce, expiration date and timestamp.

3. Signature in wallet. You see the text and domain; confirm - the wallet returns the signature.

4. Validation and session. The site checks the signature on your public key and issues a session token (usually a JWT/HTTP cookie).

5. Re-entry. No signature is required while the session is valid. After the deadline - a new request.

💡 Important: this is a signature of the message, not a transfer of funds. There is no network fee.

3) Step by step: how to sign in with a Web3 wallet

1. On the site, click Connect wallet/Sign in.

2. Select Extension or WalletConnect (QR).

3. Check the domain and the requested network (if specified).

4. Confirm the connection; wait for the Sign Message/Sign-In window to appear.

5. Carefully read the message: domain, address, nonce, expiration date.

6. Click Sign. You will see that the interface has changed to an account/profile.

4) Frequent authorization options

SIWE (Sign-In With Ethereum). De facto standard for EVM networks; there are analogues for other networks (Solana Sign-In, TON proof, etc.).

Passkeys + wallet (hybrid). Some wallets support entering the wallet itself via passkey; further - signature as usual.

Account Abstraction (EIP-4337) and session keys. The application can issue a limited "session key" for spam-free activities with signatures.

5) How the service "recognizes" you after signing

The site issues a session token with a lifetime (for example, 1-24 hours) and binds it to nonce and address.

Each time you request the API, the token confirms your authorization.

Unlogged - deleting a token (Logout button), forced - after the expiration/change of the wallet.

6) Security: what to check before signing

Domain. Does the domain in the wallet match the tab domain? (Homographs and subdomain clones are a red flag.)

Message text. There must be a target (login), nonce, chainId (if appropriate), expiration date and domain. No hidden'approve/permit '.

Signature type. This is a Message/Personal Sign, not a Transaction. If you see a gas/commission request - this is not an authorization.

WalletConnect. The DApp name in the request matches an open site; QR - from the official page.

Hardware wallet. For important accounts, confirm the signature on the device screen.

7) Best practices for the user

Split wallets. "Public login/game" vs "cold for storage."

Minimum extensions and a separate browser profile for Web3.

Bookmarks. Go to services only from your bookmarks, not from search/chats.

Regular razlogin. Close sessions on shared/working devices.

Revok is right. Authorization does not issue token rights, but after interacting with DApp, check and revoke unnecessary approve/permit.

Logs. Keep date/domain/login address if critical (corporate cases).

8) Developer/Operator Practices

Strict SIWE format. Include domain, nonce, term, chainId; validation on the backend.

Short sessions + refresh. Less chance of stealing a token. Cookie — HttpOnly, Secure, SameSite.

Binding to the User-Agent/IP (as appropriate) and the ability to recall all sessions.

Multi-chain support. SIWx (EVM), Solana Sign-In, TON-proof; Display the active network.

Anti-phishing. Show a large domain in a modal, add your own anti-phishing phrase in your profile.

Optional AA/Session keys. Limit permissions: time, methods, limits.

9) Typical mistakes and how to avoid them

Signed "something" without reading. Solution: check that it is Message, not Transaction; read domain and target.

WalletConnect to a fake application. Solution: check the name/domain in the modal; scan QR on the official page only.

Eternal sessions on someone else's PC. Solution: exit manually; use private windows/profiles.

Purse mixing. Solution: separate "login/game" and "cold."

Phishing through "bonus verification/airdrop." Solution: authorization is not about 'approve/transfer'. At gas type - cancellation.

10) User checklist (30-60 seconds)

Opened a site from a bookmark, the domain is the same in the browser and in the wallet window.
In the modal - Connect, then Sign message, not "Send/Approve."
The text contains nonce, domain, login, expiration date.
For important accounts I use a hardware wallet.
After work - Logout, close unnecessary tabs/DApp connections.

11) Mini-FAQ

Is wallet authorization free? Yes, this is the signature of the message without gas.

Can the site write off tokens at login? Not if you sign the message. Write-off requires/approve transaction.

What if I lose my wallet? Sessions will expire, but access to accounts on sites will not return without a new key. Make a seed reserve and use "cold."

Can I log in from my phone? Yes: WalletConnect (QR/deep link) or mobile extension/built-in wallet browser.

Is this replacing KYC? No, it isn't. Authorization confirms ownership of the address, KYC - customer law.

Logging in through a Web3 wallet is a convenient and secure way to log in without passwords: you sign a readable message (SIWE), the service checks the signature and issues a session. The main thing is discipline: your bookmarks, checking the domain and signature text, separating wallets, hardware confirmation for important accounts and regular logout. Then Web3 authorization will give both comfort and real security.