> For the complete documentation index, see [llms.txt](https://ftcoders.first-tech.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ftcoders.first-tech.com/first-tech-ttp-sdk/login-and-authentication.md).
# Login and Authentication
**Objective**
This section defines the **minimum requirements** for the login and **two-factor authentication (2FA)** flow, ensuring secure, clear, and accessible access to the sales environment, based on UX best practices and data protection standards.
Insights
* Authentication structure should be compatible with **offline contexts** (e.g., reconnection handling, secure caching) **where applicable**.
* This flow must comply with security regulations required for proximity-based payments via NFC (e.g., PCI MPoC).
***
## Login Screen with Empty Fields
### 01 - Email and password fields
Must appear empty with clear placeholders (e.g., `example@email.com`, `Password123@`)
{% hint style="success" %}
**Mandatory:**
The “Login” button must only be enabled when both fields are correctly completed.
{% endhint %}
{% hint style="info" %}
**Recommended:**
Include a “Forgot your password?” link for recovery.
{% endhint %}
***
## Login Screen with Credentials Filled
### 02 - “Login” button (enabled)
Must be visually highlighted. Tapping it initiates sending a verification code to the registered email.
{% hint style="success" %}
**Mandatory:**
Provide immediate visual feedback when the button is tapped (e.g., loading animation).
{% endhint %}
{% hint style="info" %}
**Recommended:**
Include a confirmation cue (visual or audio) after login attempt.
{% endhint %}
***
## Two-Factor Authentication (2FA) Code Entry
### 03 - Security info message
Must inform the user that a verification code has been sent to their email, partially masked (`us****@email.com`)
### 04 - Code input fields (6 digits)
Must support auto-advance on input and visual feedback per digit.
{% hint style="success" %}
**Mandatory:**
Show countdown timer to resend the code (e.g., “Resend code in 00:30”)
{% endhint %}
{% hint style="info" %}
**Recommended:**
Automatically validate the code once all digits are entered.
{% endhint %}
***
## Code Fully Entered
### 05 - Complete 2FA code
Must automatically enable the “Login” button once all digits are valid
{% hint style="success" %}
**Mandatory:**
After code validation, user must be redirected to the sales environment.
{% endhint %}
{% hint style="info" %}
**Recommended:**
Use smooth visual transitions to reinforce successful authentication.
{% endhint %}
***
## Access to Sales Environment
Show the sales home screen. This screen must display:
* Vendor name and photo
* Search bar
* Product list with name, category, price, stock
* Bottom navigation bar with visible sections: Home, Cart, Charge, User
{% hint style="success" %}
**Mandatory:**
Navigation is only accessible after full credential + code validation.
{% endhint %}
{% hint style="info" %}
**Recommended:**
Customize this screen with relevant info based on vendor profile.
{% endhint %}
> **Each component and user experience of the sales screen will be discussed in more detail in the next session.**
***
## Mandatory Messages
* When the code is incorrect:
> Invalid code. Please check the number sent to your email and try again.
* When the code expires:
> Code expired. Please request a new one to continue.
***
## Expected Behaviors
* The app must provide **visual and/or audio feedback** at each stage.
* The “Login” button must respect validation logic.
* Two-factor authentication is **mandatory** before accessing the sales system.
* Sensitive data (email, password) must be handled with **masking and encryption**, in accordance with LGPD and PCI standards.
---
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