Sign in with Ethereum

SiwePlugin lets users sign in with an Ethereum wallet. The browser asks the wallet to sign an ERC-4361 message that contains a server-issued nonce; the server verifies the signature, links the wallet address to a user and issues a session. The bundled verifier supports externally owned accounts (EIP-191 personal sign); contract wallets and chain-specific checks are your responsibility through the SiweVerifier trait.

Schema

alibi generate --plugins siwe -o src/auth_schema.rs

Adds the wallet_address table (user_id, address, chain_id, is_primary, created_at).

Setup

use crate::auth_schema::AppAuthSchema;
use alibi::plugins::siwe::{Eip191Verifier, RandomSiweNonce};
use alibi::plugins::{SiweConfig, SiwePlugin};
use alibi::sqlx::SqlxStore;
use alibi::{AuthConfig, AuthResult, BetterAuth};
use std::sync::Arc;

async fn build_auth(
    config: AuthConfig,
    store: SqlxStore<AppAuthSchema>,
) -> AuthResult<BetterAuth<AppAuthSchema>> {
    BetterAuth::<AppAuthSchema>::new(config)
        .store(store)
        .plugin(SiwePlugin::new(SiweConfig::new(
            "app.example.com",
            Arc::new(RandomSiweNonce),
            Arc::new(Eip191Verifier),
        )))
        .build()
        .await
}

SiweConfig::new(domain, nonce_provider, verifier); domain is the host wallets show to the user and that the signed message must contain.

Flow and endpoints

Method	Path	Purpose
POST	/siwe/nonce (alias /siwe/get-nonce)	Issue a nonce (valid 15 minutes, single use)
POST	/siwe/verify	Verify { "message", "signature", "email"? } and sign in

1. The client requests a nonce: POST /siwe/nonce with an empty body → {"nonce":"c2Vj…"}.
2. The client builds the ERC-4361 message (domain, address, statement, URI, chain id, nonce) and has the wallet sign it.
3. The client posts {"message":"…","signature":"0x…"} to /siwe/verify. The server checks the domain, nonce and signature, consumes the nonce, finds or creates the user for the address and sets the session cookie.

curl -X POST http://localhost:3000/api/auth/siwe/nonce -H 'Origin: http://localhost:3000'
# {"nonce":"WT7pXf3sQ1uJ8Kc2LmRz0aVbNd4YhEgO"}

Nonces must be 8–250 ASCII alphanumeric characters. A first-time wallet gets a new user whose email is <address>@<email_domain_name> — or <address>@siwe.placeholder.invalid when you set no domain — whose name is the ENS name (when ens_lookup finds one) or the wallet address, and the address is stored as that user’s primary wallet.

Configuration

SiweConfig field	Default	Effect
domain	required	Expected message domain
nonce_provider	required	SiweNonceProvider::get_nonce(); RandomSiweNonce generates 32 random characters
verifier	required	SiweVerifier::verify_message(SiweVerification) — Eip191Verifier for EOAs
email_domain_name	none	Domain for generated emails (<address>@<domain>); without it, <address>@siwe.placeholder.invalid
anonymous	true	true: wallets need no email. false: email is required at verification
ens_lookup	none	EnsLookup::lookup(address) → EnsProfile { name, avatar } to fill the user’s name and image

When anonymous is false, an email is required — and an existing user with that email is never linked to a wallet by the email alone, so a stranger cannot take over an account by claiming its address.

Support contract wallets (ERC-1271)

use async_trait::async_trait;
use alibi::plugins::siwe::{
    Eip191Verifier, SiweCallbackResult, SiweConfig, SiweVerification, SiweVerifier, RandomSiweNonce,
};
use std::sync::Arc;

struct Hybrid;

#[async_trait]
impl SiweVerifier for Hybrid {
    async fn verify_message(&self, input: SiweVerification) -> SiweCallbackResult<bool> {
        // Try the EOA check first; fall back to an `isValidSignature` call over your RPC.
        if Eip191Verifier.verify_message(input.clone()).await? {
            return Ok(true);
        }
        Ok(false) // call your JSON-RPC provider for chain `input.chain_id` here
    }
}

fn config() -> SiweConfig {
    SiweConfig::new("app.example.com", Arc::new(RandomSiweNonce), Arc::new(Hybrid))
}

SiweVerification provides the original message, the signature, the EIP-55 address, the numeric chain_id and a CAIP-122 cacao view. A callback can reject with SiweCallbackError::Api(AuthResponse) for a custom HTTP error or Failed(message) for provider failures, which become a generic 500-style error.

Security notes

• Nonces are bound to the server, expire after 15 minutes and are consumed on verification — replay fails.
• Always show wallet users your domain in the sign-in message; wallets warn on mismatches, and the server rejects them.
• Wallet addresses are case-insensitive hex; the server stores the EIP-55 checksummed form.

Frontend

See the official SIWE guide.