Username

Username sign-in is part of EmailPasswordPlugin.

Setup

better-auth-rs generate --plugins username -o src/auth_schema.rs

Apply the schema changes, then enable username support:

use crate::auth_schema::AppAuthSchema;
use better_auth::plugins::EmailPasswordPlugin;
use better_auth::sqlx::SqlxStore;
use better_auth::{AuthConfig, AuthResult, BetterAuth};

async fn build_auth(
    config: AuthConfig,
    store: SqlxStore<AppAuthSchema>,
) -> AuthResult<BetterAuth<AppAuthSchema>> {
    BetterAuth::<AppAuthSchema>::new(config)
        .store(store)
        .plugin(EmailPasswordPlugin::new().enable_username(true))
        .build()
        .await
}

Options

Sign-in uses /sign-in/username; email signup also accepts a username. The default policy lowercases ASCII usernames and allows 3–30 characters.

Use username_config to change length bounds, normalization, validators, or input policies. Validation order depends on the selected pre/post-normalization policy; see the username implementation for the complete options.

Frontend

See the official username guide.