Causeway by Larkspur

The passwordless future is already shipping. Lift conversion on your customer-facing apps and websites with a faster, safer sign-in built on passkeys.

Talk to an engineer Get started with Causeway
Two colleagues working side by side on laptops at a shared wooden table — photo by MART PRODUCTION on Pexels

Turn a passkey-powered sign-in into your best conversion lever

Replace the friction passwords create with a login your customers finish on the first try. Causeway drops passkey support into the auth flow your site or app already runs, usually in an afternoon.

Move the conversion metrics that actually pay rent

Close to 31% of online purchases stall at checkout because someone cannot remember a password. Passkeys change that: creating an account and signing back in runs about four times faster than typing a credential, and that speed shows up as completed signups.

Havenly Homes BuySellRent RegisterLog in
Find the home that fits the life you are building
×
Sign in without a password
rowan.mercer@mailbox.com
Use the passkey already stored on this device to unlock your account.
Change emailSend a one-time link
BuySellRent Havenly Homes
Account settings
Personal info
Sign in & security
Manage account
Signed in successfully
rowan.mercer@mailbox.com

Retire the reset email and the SMS code bill

Give your support queue back its afternoons: no more reset tickets, no more one-time codes charged per message. A passkey carries two factors inside it, so the second step is already handled by the device your customer is holding.

Roll passkeys out gradually and watch adoption climb

Building a login that understands passwordless credentials is genuinely hard work. Causeway hands you a rollout that already works — enrolment prompts, fallbacks, and readiness reporting — paired with an experience your customers do not have to be taught.

Causeway AppsReadinessDocsSupport
Passkey readinessOpen integration guide
Share of customer sessions on devices that already support passkeys
Readiness over time across signed-in traffic
Readiness by platform
Readiness by region
Causeway
Quickstart
Overview
Authentication
Login settings
Registration
Sessions
Methods
Automation
Users
Events
Branding
Settings
Authentication
MethodsLoginRegistrationSessions
Identifier types
Email address
Phone number
Passkeys
Prompt at first sign-in
One-time links
Email fallback
Federated sign-in
Workspace directory
Developer platform
Device account

Raise the floor on account security and shut down phishing

Passkeys are not only quicker than a password — they are bound to your domain, so a convincing lookalike page has nothing to steal. Use Causeway to harden the accounts your customers trust you with, and keep credential stuffing out of your logs.

Take the work out of going passwordless

Ready for passkeys? With Causeway by Larkspur you can support passwordless sign-in at whatever pace suits your roadmap and your customers.

Havenly Homes BuySellRent RegisterLog in
The listings worth your Saturday
×
Log in
rowan.mercer@mailbox.com
Or sign in without a password using the passkey on this device.

Causeway Bridge

Add passkey logins alongside the password flow you already run, so customers choose how they sign in and your team keeps a familiar fallback while adoption builds.

  • Drops into your existing auth stack
  • Scales up as passkey adoption grows
  • Sets the bar for sign-in in your category
Try Causeway Bridge Book a walkthrough
Ridgeway Clinic CareBilling Patient portal
Treatment plans built around your week
×
Sign in without a password
delia.okafor@mailbox.com
Unlock your chart with the passkey saved on this device.
Change emailEmail me a link

Causeway Harbor

Take the security, cost, and experience win in one move by replacing passwords outright with a full identity and authentication layer running on passkeys.

  • Fully passwordless from day one
  • Recovery flows that stay phishing-resistant
  • Identity, sessions, and audit in one place
Try Causeway Harbor Book a walkthrough

Why teams stay on Causeway

“Wiring it into our own application was genuinely simple, and I had a solid passwordless login running before the end of the afternoon.”
Marisol TrevinoEngineering lead
Portrait of Marisol Trevino — photo by Jake Nackos on Unsplash
“Signing in without a password is the part of our product people mention unprompted. It is convenient and it just gets out of the way.”
Priya RaghunathanChannel manager
Portrait of Priya Raghunathan — photo by Foto Sushi on Pexels
“Incredibly straightforward to work with, and the documentation covers a wide enough range of languages that nobody on my team got stuck.”
Desmond AchebeSenior software developer
Portrait of Desmond Achebe — photo by Korede Adenola on Pexels

Built for developers,
by developers

Add first-rate passkey authentication to your product in an afternoon, then go back to building the thing you actually care about.

APIs and SDKs you can read

Drop it into the stack you already run: JavaScript, TypeScript, Python, Ruby, Go, and a dozen more.

Migration without a big bang

Bulk-import the accounts you have, or provision them just in time as people return. Our team will sit in the planning call.

Support when it is on fire

Real engineers on the other end, ready to help you launch and quick to answer when something breaks at 2am.

Causeway products

Pricing that fits your websites and apps

Verify it is you
Tired of passwords?
Sign in with the method your device already uses to unlock.
Browser
Confirm your identity to continue.

Causeway Bridge

Add passkey logins to the authentication flow you already have.

Pricing
  • First 1,200 monthly actives — free
  • Beyond that — $0.03 per active / month
  • Enterprise — talk to us about volume
Features
  • Works with existing auth solutions
  • Supports passkeys and passwords together
  • Transition at your own pace
Start building
Northline Market login
Enter the code below to sign in. It expires in five minutes.
418 209
Register with a passkey
Passkeys are a simpler, safer alternative to passwords.
Check your messages
A one-time link is on its way to your phone.

Causeway Harbor

Go fully passwordless with a standalone authentication service.

Pricing
  • First 1,200 monthly actives — free
  • Beyond that — $0.06 per active / month
  • Enterprise — talk to us about volume
Features
  • Replaces the auth service you run today
  • Passkeys first, with passwordless fallbacks
  • User and identity management included
Start building

Dive deeper into Causeway by Larkspur

Causeway documentation

How Causeway works end to end, and how to get Bridge or Harbor running inside your own product.

Read the documentation

Growth after the password

What happens to funnel metrics when the friction of a forgotten credential leaves the checkout entirely.

Watch the session

Passkey FAQs

What are passkeys?

A passkey is a login credential that takes the place of a password entirely. It lets someone sign in to an account on any of their devices using the biometric or screen lock that device already has.

Under the hood every passkey is two halves. The private half never leaves the customer's device and is never shared with the site they are signing in to. The public half is safe to hand over, which is the part your application stores.

Why are passkeys better than passwords?

Nothing reusable is typed, sent, or stored, so there is no credential to phish, stuff, or leak in a breach. They are also bound to your domain, which means a lookalike page cannot collect anything usable.

What other kinds of passwordless sign-in does Causeway support?

Alongside passkeys, Causeway ships one-time email links, one-time codes over SMS, and federated sign-in through your workspace directory — useful as fallbacks while a device catches up.

What is the difference between Causeway Harbor and Causeway Bridge?

Bridge layers passkeys onto the authentication service you already operate. Harbor replaces it, taking over identity, sessions, and recovery so that no password exists in the system at all.

Ready to embrace passkeys?

Give your customers the passwordless sign-in they already expect. Causeway simplifies the login, lifts conversion, and takes cost out of your support queue.

Get started with Causeway