With the arrival of the Vercel AI SDK, Next.js has become one of the strongest frameworks for building AI-powered web apps. If you want to share a Next.js AI application privately inside your company, you need to add user authentication. This article compares popular services and techniques that minimize implementation effort (rather than building an auth server from scratch).

Authentication for internal apps differs from that for public apps in several key ways:

Signup must be restricted

If anyone can self-sign-up, a third party who discovers the URL could create an account. Internal apps therefore need signup disabled or invite-only access.

Complex, per-app role management

Most companies run more than one internal app. A robust identity layer must let you grant different permissions in each app—crucial for data governance.

Log collection and monitoring

For compliance and auditing you must track who does what. Access logs and user actions should be stored together so you can trace behavior back to individual people.

Squadbase – Built-in Auth & Roles with a Modern DX

Squadbase is a delivery platform with built-in authentication for internal apps. It supports Next.js, and also frameworks such as Streamlit and Ollama.

Built-in authentication

Apps deployed to Squadbase are accessible only to team-mates you invite from the Squadbase dashboard. Because auth is part of the platform, you write zero extra code.

Simply connect a GitHub repo to enable continuous deployment in a secure runtime—similar to Vercel or Netlify, but purpose-built for internal software.

Role assignment

Squadbase lets you define:

• Team roles – who can deploy or administer the platform
• Project roles – per-app permissions usable in your code via the SDK

import { createClient } from "@squadbase/sdk/nextjs"

const squadbase = await createClient(
  process.env.NEXT_PUBLIC_SQUADBASE_PROJECT_ID,
  {
    mockUser: { /* … */ }
  }
)

export default async function ServerComponent() {
  const { data: user, status } = await squadbase.getUser()

  if (status === "error") {
    return <p>error</p>
  }

  return <p>Hello, {user.username}</p>
}

Because roles are set per project, one platform can manage auth for many apps.

Log monitoring & user analytics

Squadbase automatically collects runtime logs and access logs. Aggregated analytics are available in a dashboard, helping you operate and improve internal tools.

(Analytics screenshot)
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Clerk – Gorgeous UI Components

Clerk has exploded in popularity as an auth solution for Next.js. Alongside the backend, it ships a polished UI kit you can integrate in a few lines.

Features useful for internal apps

• Signup restrictions – Set “Restricted” mode so only invited users can sign up (invites are sent from the Clerk dashboard).
• Auth-flow UI – Prebuilt screens for sign-up / sign-in, profile, social-account linking, etc.
• SSO – Enable OAuth or SAML single sign-on with a few dashboard clicks.

Caveats

• Pricing – Free for up to 10 000 MAUs. But features like Organizations (needed for role assignment) and block-lists start at $25 / month. Realistically, budget at least that much.
• Multiple apps – If a marketing manager needs admin rights in the marketing app but read-only rights in the company-wide app, you’ll have to model that with Organizations or run multiple Clerk projects.

Auth0 – Enterprise-Grade Reliability

Auth0 offers a battle-tested identity platform that balances enterprise requirements with good DX.

Internal-app highlights

• SSO – Configure OAuth or SAML providers, including seamless Okta integration, straight from the dashboard.
• Role management – Assign roles to individual users via the UI or API.

Caveats

• Signup restrictions – You can disable signup and create granular invite flows, but only certain connection types support it, and you’ll likely need to script the Management API.
• Multiple apps – Per-app roles require either multiple tenants or a carefully designed role scheme that encodes app scopes—both add operational complexity.

IP-Based Restriction via Middleware

If you don’t need per-user authentication and just want to block outsiders, you can implement a simple IP allow-list in Next.js middleware.

// middleware.ts

import { NextRequest, NextResponse } from 'next/server'

const IP_WHITELIST = ['xxx.xxx.xxx.xxx', 'yyy.yyy.yyy.yyy'];

export async function middleware(request: NextRequest) {
  const res = NextResponse.next();

  let ip: string = request.ip ?? request.headers.get('x-real-ip') ?? '';

  if(!ip && forwardedFor){
    const forwardedFor = request.headers.get('x-forwarded-for');
    ip = forwardedFor.split(',').at(0) ?? 'Unknown';
  }

  if(!IP_WHITELIST.includes(ip)){
      return NextResponse.redirect('/access-denied');
  }

  return res;
}

Final Thoughts

Choose the option that fits your security needs, operational capacity, and budget—then ship that AI-powered Next.js app with confidence.