SvelteKit Authentication

Login, route protection, sessions, and user management in your SvelteKit app. Paste one prompt into your AI agent, or wire it yourself with one call in your root layout.

Quickstart in minutes

Enterprise-grade & compliant by default

Add auth to my SvelteKit app using The Bridge.

Your SvelteKit app, wired in

Login handledVisitors without a session are sent to the hosted login and brought back.
Routes locked by defaultdefaultAccess: 'protected' guards everything; you list what is public.
Sessions handledSigned tokens issued, verified, and renewed for you.
One reactive user store$user in any component, with plan and roles on the same object.

The fastest way to integrate

Auth by asking.

The Bridge is agent-native. Install the Bridge CLI, paste one prompt, and your coding agent wires authentication into your SvelteKit app.

✦ CLI-nativeClaude CodeCursorAny coding agent

Your agent does the wiring, you ship the product

Install the Bridge CLI, then paste the prompt below into your agent. It authorizes the CLI in your browser (creating your account right there if you are new), detects Svelte, installs the SDK, wires the layout, and registers the settings your app needs.

Prefer to wire it yourself? See the SDK and CLI paths below.

Why The Bridge for SvelteKit

Everything after login, already there

The login form is the visible part. The wins are everything you no longer have to build behind it.

Every sign-in method

Email, passkeys, magic link, and Google, toggled from the Control Center with no redeploy.
UX
Routes locked by default

Public routes are declared; everything else needs a session before it renders.
Security
Enterprise SSO ready

When the security questionnaire arrives, connect their identity provider and keep your architecture.
Enterprise
Authorization built in

Roles, plan, and feature flags ride the same user object, and route rules can gate by feature flag.
RBAC
Built for teams

Multi-tenant user management out of the box: workspaces, invites, and roles included.
B2B
Session management

Sessions issued, renewed, and revoked centrally. Block a user and they are out on the next request.
Control
MFA included

Multi-factor authentication ships with the platform, no extra vendor to integrate.
Trust
API tokens for machines

External services and scripted callers authenticate with API tokens you can revoke at any time.
M2M

Prefer to wire it yourself?

Pick the workflow that matches how you build.

SDK

// src/routes/+layout.ts
import { bridgeBootstrap } from '@nebulr-group/bridge-svelte';

export const load = async ({ url }) => {
  await bridgeBootstrap(
    url,
    { appId: BRIDGE_APP_ID },
    { rules: [{ match: '/', public: true }],
      defaultAccess: 'protected' },
  );
  return {};
};

Read the full quickstart in the docs →

And of course

First-class SDKs for every stack

Type-safe, batteries-included SDKs with drop-in components, and the same clean user object everywhere.

Next.js

Svelte

Astro

Node

FastAPI

Laravel

Flutter

React

Angular

Nuxt

Deno

Python

Rust

Ruby

Kotlin

Vue

SolidJS

Remix

Bun

Django

PHP

.NET

NestJS

…and 24+ frameworks & languages supported. Hover to pause, drag or swipe to explore.

Check out our Svelte SDK on GitHub

Hand-Rolled SvelteKit Authentication vs. The Bridge

What a hand-built SvelteKit auth stack actually costs you, versus one call in your root layout.

Building it yourself

Write your own route guard, auth stores, and refresh logic
Stand up login, session, refresh, and logout endpoints
Store tokens safely and handle renewal and revocation
Add SSO, more sign-in methods, and user management when customers ask

With The Bridge

One bootstrap call, routes locked by default
Login hosted for you or dropped into your UI, no pages to build
Sessions issued, verified, and renewed for you
SSO and multi-tenant user management on the same user object

Common questions

How can I implement authentication in SvelteKit?

With The Bridge it is one call in your root layout, wiring login, sessions, and route protection in a single load function, and one layout component that keeps guarding as users navigate. Visitors without a session are sent to the hosted login and brought back to the page they wanted, or to your own in-app login if you configure one. The quickstart walks through both files.

How do I protect routes in SvelteKit?

You list which routes are public in one rules array, and every other route requires login automatically because the default is protected. New routes are born protected, so nobody can forget to guard one. The route guards docs show the exact setup.

Does this work with plain Svelte or only SvelteKit?

The SDK is built for SvelteKit: the current @nebulr-group/bridge-svelte 0.4.x line supports SvelteKit 2 with Svelte 5. If you are on plain Svelte, SvelteKit is the supported path. Check the quickstart for the currently supported range.

Does this use JWT authentication?

Yes. Sessions are standard signed JSON Web Tokens issued by The Bridge and verified against published public keys, so your own backend can verify them too. To see what lives inside a token and how verification works, read JWT authentication explained.

Do I get a login page or do I build one?

You get one. By default unauthenticated visitors are redirected to The Bridge's hosted login, which carries every sign-in method you have enabled. If you want the form inside your own app instead, the SDK ships components for that too, including login, signup, magic link, and passkeys.

How do I read the logged-in user in a component?

Through a reactive store the SDK exports: read the user anywhere in your components, with fields like email, role, and workspace, and everything updates on login and logout without any wiring. The user token docs show the exact code.

How do I handle authorization and roles in SvelteKit?

Configure roles and permissions in the Control Center and they arrive inside the signed token, as claims on the same user object your login returns. Branch on the user's role in your components, gate whole routes by feature flag in the same rules array, and let your API authorize from the same source. The roles docs cover the setup end to end.

Where does server-side rendering fit in?

The SDK does its work in the browser: the quickstart sets ssr = false so the route guard and session run client-side, which is the natural fit for an app behind a login. Your server-side API still verifies the same signed tokens, so protected data stays protected regardless of where rendering happens.