Every app has a front door. Build yours on Lintel.

Sign-up, sign-in and user management that drops into React, Next.js and every stack in between. Ship the front door this afternoon, then spend the quarter on everything behind it.

Start building free

Start building free

$ npm i @lintel/react

$ npm i @lintel/react

Free for your first 5,000 users. No card required.

Fieldnote

Sign in to Fieldnote

Welcome back. Pick up where you left off.

Google

GitHub

Apple

or

Email address

mira@fieldnote.co

Continue

No account?

Sign up

Secured by

Lintel

Fieldnote

Sign in to Fieldnote

Welcome back. Pick up where you left off.

or

Email address

mira@fieldnote.co

Continue

No account?

Sign up

Secured by

Lintel

Two-step verification

Enter the code from your authenticator app.

4

8

1

9

2

6

Two-step verification

Enter the code from your authenticator app.

4

8

1

9

2

6

New sign-in

now

Chrome on macOS · Lisbon, Portugal

It was me

Revoke session

New sign-in

now

Chrome on macOS · Lisbon, Portugal

It was me

Revoke session

The front door for 9,000+ products, from weekend launches to public companies.

Fieldnote

Kestrel

Halcyon

Oakhaus

PARALLAX

tandem

Prebuilt components.
Styled like you built them.

Drop in <SignIn />, <UserButton /> and the rest. Every flow is accessible, translated into 40 languages and themeable down to the pixel.

Fieldnote

Sign in to Fieldnote

Welcome back. Pick up where you left off.

Google

GitHub

Apple

or

Email address

mira@fieldnote.co

Continue

No account?

Sign up

Secured by

Lintel

Email, passwords, passkeys, magic links and 20+ social providers in one adaptive flow.

app/sign-in/page.tsx

import { SignIn } from '@lintel/nextjs'
 
export default function Page() {
  return (
    <SignIn
      appearance={{
        theme: 'light',
        variables: {
          colorPrimary: '#E0401E',
          borderRadius: '10px',
        },
      }}
    />
  )
}

Fieldnote

Sign in to Fieldnote

Welcome back. Pick up where you left off.

Google

GitHub

Apple

or

Email address

mira@fieldnote.co

Continue

No account?

Sign up

Secured by

Lintel

Email, passwords, passkeys, magic links and 20+ social providers in one adaptive flow.

app/sign-in/page.tsx

import { SignIn } from '@lintel/nextjs'
 
export default function Page() {
  return (
    <SignIn
      appearance={{
        theme: 'light',
        variables: {
          colorPrimary: '#E0401E',
          borderRadius: '10px',
        },
      }}
    />
  )
}

Four minutes to your first sign-in.
We timed it.

Four snippets, pasted in order. Sessions, middleware and webhooks come along for free.

  1. 01

    Install the SDK

    One package with types included. No peer-dependency scavenger hunt.

    Terminal

    $ npm install @lintel/nextjs
     
    added 3 packages, and audited 287 packages in 2s
     
    found 0 vulnerabilities

  2. 02

    Add your keys

    Copy two keys from the dashboard. Development instances work on localhost out of the box.

    .env.local

    # Dashboard → API keys
    NEXT_PUBLIC_LINTEL_PUBLISHABLE_KEY=pk_test_ZmllbGRub3RlLmxpbnRlbC5kZXYk
    LINTEL_SECRET_KEY=sk_test_••••••••••••••••

  3. 03

    Wrap your app

    The provider handles sessions, token refresh and multi-tab sync. You won’t think about cookies again.

    app/layout.tsx

    import { LintelProvider } from '@lintel/nextjs'
     
    export default function RootLayout({ children }) {
      return (
        <LintelProvider>
          <html lang="en">
            <body>{children}</body>
          </html>
        </LintelProvider>
      )
    }

  4. 04

    Drop in the door

    Render <SignIn /> and you’re live: social sign-in, email codes, passkeys and bot protection, all on by default.

    app/sign-in/page.tsx

    import { SignIn } from '@lintel/nextjs'
     
    export default function Page() {
      return <SignIn />
    }

Terminal

.env.local

app/layout.tsx

app/sign-in/page.tsx

$ npm install @lintel/nextjs
 
added 3 packages, and audited 287 packages in 2s
 
found 0 vulnerabilities

Elapsed

0:20

Your customers come with teams.
Lintel comes with the org chart.

Organizations, roles, invitations and enterprise SSO are built in. Sell to a five-person startup on Monday and a 5,000-seat bank on Friday without touching your schema.

Members and invitations

Invite by email and pick a role. Pending invites expire on their own, so nobody has to clean up.

Fieldnote

24 members

Search members

Invite

Member

Role

Joined

Mira Castell

mira@fieldnote.co

Admin

Mar 2024

Daniel Novak

daniel@fieldnote.co

Member

Jun 2024

Priya Raman

priya@fieldnote.co

Billing

Jan 2025

Jonas Weber

jonas@fieldnote.co

Member

Aug 2025

Lena Fischer

lena@fieldnote.co

Member

Sep 2025

Kofi Mensah

kofi@fieldnote.co

Admin

Oct 2025

sana@fieldnote.co

Invited by Mira

Member

Expires in 6 days

One account, many workspaces

People move between organizations without signing out, and your app always knows which one is active.

Fieldnote

Admin · 24 members

Active

Kestrel Labs

Member · 112 members

Halcyon

Billing · 9 members

Verified domains

Anyone who signs up with a company address lands in the right organization. No invite needed.

fieldnote.co

Verified

Auto-join new teammates

New sign-ups from @fieldnote.co join as Member.

Enterprise SSO, set up by your customer

SAML and OIDC with any identity provider. IT admins configure it themselves from a guided flow, not your on-call engineer.

Okta Workforce

SAML

Connected

Microsoft Entra ID

OIDC

Connected

Google Workspace

SAML

Step 2 of 3

JumpCloud Directory

SCIM

Syncing 1,204 users

Roles and permissions

Define custom roles with fine-grained permissions, then check them in one line, on the server or the client.

Permission

Admin

Billing

Member

org:invoices:approve

org:members:invite

org:notes:edit

if (!has({ permission: 'org:invoices:approve' })) {
  return forbidden()
}

Load-bearing security.
Quiet until someone tries the door.

Every attempt is scored before it reaches your app. Bots bounce off, credential stuffers stall, and real people walk straight through.

Walked in0
Asked for a second factor0
Turned away0
Walked in0
Asked for 2FA0
Turned away0

Bot and abuse detection

A model trained on more than a billion sign-in attempts, retrained every hour.

Breached-password checks

Every password is checked against 12 billion leaked credentials at sign-up and sign-in.

Multi-factor and passkeys

Authenticator apps, SMS, backup codes and passkeys. Require them per role.

Session control

See every signed-in device. Revoke one, or all of them, the moment something looks off.

Brute-force lockout

Progressive delays and lockouts, tuned per account and per network.

Throwaway email blocking

Stop free-trial farming from disposable domains and endless plus-addresses.

Audited every year and pen-tested twice a year by independent firms. The security questionnaire is already filled in.

SOC 2

Type II

HIPAA

BAA ready

GDPR

EU hosting

CCPA

Compliant

Why a lintel?

A lintel is the beam laid across two posts to make a doorway. It is one of the oldest ideas in building, older than the arch. Nobody looks up at it. Everything leans on it.

Identity works the same way. Two posts, your users and their organizations. One beam, the session that spans them. Get it right and nobody notices. Get it wrong and nothing else stands.

Left post

Users

Right post

Organizations

The beam

Sessions

Teams that stopped
thinking about auth.

From weekend projects to public companies, more than 9,000 products open their doors with Lintel.

1.4B

sign-ins handled last month, at a median of 38 ms.

+2,400 teams joined in October

Fieldnote

We deleted eleven thousand lines of auth code and shipped SSO the same week. Enterprise deals stopped stalling on security review.

Maya Okafor

CTO, Fieldnote

3:58

median time from npm install to a first real sign-in.

Measured across 31,000 new projects

99.99%

API uptime over the last 90 days.

90 days ago

Today

Halcyon

Our first bank customer sent a 300-question security review. Lintel’s answers covered 280 of them. We closed in three weeks.

Tomás Ferreira

Head of Engineering, Halcyon

−38%

drop-off at sign-up after Kestrel switched to passkeys and one-tap Google.

Kestrel

Free until you’re big.
Fair once you are.

Your first 5,000 monthly users are free on every plan. No card and no trial clock.

Monthly

Annually

Save 20%

Starter

$0

forever

For side projects, prototypes and launch day.

Start for free

5,000 monthly active users

Email, password and social sign-in

Every prebuilt component

Organizations up to 5 members

Community support

Pro

Most popular

$29

per month

For products with paying customers and a support inbox.

Start a 14-day trial

5,000 users included, then $0.01 each

Passkeys, MFA and bot protection

Unlimited organizations and custom roles

Your domain, no Lintel badge

Email support, one-day response

Enterprise

Custom

For teams with a security review to pass and a procurement team to please.

Talk to sales

SAML, OIDC and SCIM provisioning

99.99% uptime SLA

HIPAA BAA and audit logs

A named solutions engineer

Volume pricing

Monthly active users48,000
1k10k100k1M
$459per month on Pro, billed monthly

Questions,
answered.

The quickstart covers most of the rest. Bigger rollout? See Enterprise.

Can I migrate from Auth0, Firebase or my own auth?

Who owns the user data?

What counts as a monthly active user?

Do I have to use your UI?

Is Lintel ready for enterprise customers?

What happens if Lintel goes down?

Open the door.

Free for your first 5,000 users. Live in about four minutes.

Create your account

Read the quickstart

Open the door.

Free for your first 5,000 users. Live in about four minutes.

Create your account

Read the quickstart

Open the door.

Free for your first 5,000 users. Live in about four minutes.

Create your account

Read the quickstart

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