> 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/app-initialization.md).
# App Initialization
**Objective**
This section defines the **minimum requirements** for the application startup flow, ensuring that the device environment is suitable and secure to process proximity-based payments (Tap to Pay).
**Insights**
* Using friendly illustrations is recommended to **reduce friction** during verification.
* The “Continue” button must be visually and functionally linked to a successful security validation.
* This step is **mandatory** to ensure compliance with proximity payment security best practices (e.g., PCI MPoC).
***
## Welcome Screen
### 01 - Illustrative icon
Must represent the store context. Custom branding is allowed, as long as it maintains legibility and proper contrast.
### 02 - Welcome message
Must include the store name and a short message guiding the user through the app.
### 03 - “Enter” button
Must be clearly highlighted as the main action. Triggers the mandatory security check before granting access to the app.
{% hint style="success" %}
**Mandatory:**
A clear and visible button must be available to start the environment verification before enabling the payment functionality.
{% endhint %}
***
## Security Checklist
### 04 - Magnifying glass illustration
Optional visual element. Recommended to indicate inspection or safety check.
### 05 - Verification checklist
Must include all items that are checked during the security scan.
{% hint style="success" %}
**Mandatory:**
Each item must visibly show either valid or invalid, so the user can clearly understand which requirements are met.
{% endhint %}
***
## Environment Ready
### 06 - All items marked as checked
All conditions must be positively validated.
### 07 - “Continue” button (enabled)
Must be displayed as the main action and only enabled when all conditions are fulfilled.
{% hint style="success" %}
**Mandatory:**
The “Continue” button should only become available when all items in the checklist are validated. The action must lead to the sales interface.
{% endhint %}
***
## Environment with Restrictions
### 08 - Invalid item highlighted in red
Example: NFC deactivated. The item must be visually emphasized with a red icon and clear explanatory label.
### 09 - “Continue” button (disabled)
The button must be clearly inactive (greyed out) and non-clickable while any item in the checklist is not satisfied.
{% hint style="success" %}
**Mandatory:**
The "Continue" button must remain disabled until all checklist requirements are met.
{% endhint %}
{% hint style="info" %}
**Recommended:**
Display contextual guidance for the user, such as “Activate NFC to continue.”
{% endhint %}
***
## Expected Behaviors
* The checklist must run automatically after pressing “Enter”.
* Immediate visual feedback must be provided (green or red icon) for each checklist item.
* If any requirement fails, the interface must **clearly inform** the user in non-technical language.
* The “Continue” button must **only** be available once all validations return.
## Mandatory Messages
* When NFC is deactivated:
> **NFC is deactivated. Please activate NFC to continue using Tap to Pay.**
* When the app is running in a suspicious environment:
> **Unsecure environment detected. Please check your device's integrity.**
---
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