You send, you're in!

A straightforward authentication flow: your app requests a session, you send a short code from your email or WhatsApp, Sendity matches the sender to the session — and you're in. Fast to use, easy to integrate, and secure by design.
See how it worksGet the source code

How Sendity works

Simple, clear steps. No passwords, no magic links. Just send a short code from your address or number so we can verify it's you.
You click Sign in
Your app asks the Sendity server to start an authentication and receives a session ID and a one-time code.
Session + code are created
The code is bound to your session on the server and shown to you in the browser.
You send the code
Send the code to Sendity via WhatsApp or email. Links under the code open your WhatsApp or email client with the code pre-filled.
Sendity receives your message
We extract the sender (phone number or email) and look up the session using the code.
Identity is verified
If the code matches the session, the app is informed and you are signed in.

It's fast, easy and secure

Designed to be obvious for users and straightforward for developers.
  • Fast for users
    No sign-up form, no forgotten passwords. Sending one short code typically takes under 10 seconds.
  • Easy to integrate
    Embed a tiny client from npm in your app and talk to a Docker-hosted server. Minimal API surface.
  • Secure by design
    One-time code, session binding and sender verification. No password storage, reduced attack surface.
  • Works with almost any app
    Web, mobile, or backend flows — Sendity integrates wherever email or WhatsApp is available.
  • Open source
    Use it as-is, audit it, or self-host. Contributions welcome.