# 11.1 Passwordless SaaS Login

*How PTERI is applied in real systems*

> This section shows **how PTERI’s single trust model is applied across different scenarios**, without changing primitives or introducing special cases.

Each use case uses the same flow: **Wallet → Signature → Verification → Outcome**

***

#### Problem

Traditional SaaS login relies on:

* Passwords
* Email resets
* MFA add-ons

These increase friction and expand the attack surface.

#### PTERI Approach

* User requests login
* Backend issues a challenge
* Wallet signs the challenge
* Backend verifies and issues session/JWT

There are:

* No passwords to store
* No recovery emails
* No OTP codes

Login becomes a **cryptographic proof of authority**.

***


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.kakrlabs.com/11.-use-cases/11.1-passwordless-saas-login.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.