> ## Documentation Index
> Fetch the complete documentation index at: https://docs.paycashless.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Definitions

Below are essential terms you’ll encounter while integrating Paycashless. Understanding these will help ensure smooth implementation, testing, and reconciliation of transactions.

## Authentication & Security

#### API Key

A private credential used to authenticate API requests. This key is passed in request headers when calling Paycashless endpoints.

#### API Secret

A private credential used for signing and verifying API requests. You must use your secret to sign requests and validate webhooks for security and integrity.

#### Signing Requests

Paycashless requires all API and webhook requests to be signed using your API Secret. This helps ensure that the request is legitimate and has not been tampered with.

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## Environments

We have two environments in Paycashless

| Environment | Details                                                                                                                                                                                        |
| :---------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Test**    | A sandbox environment used during development and testing. It allows developers to simulate payment flows and API interactions without using real money. No actual transactions are processed. |
| **Live**    | The production environment where real transactions occur. It is used to process actual payments and should only be accessed with secure, verified credentials.                                 |

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## Payments

#### Virtual Account

A unique bank account number assigned to a business or end-customer, enabling direct transfers and automatic matching of funds.

#### Pay with Transfer

A payment method that allows customers to complete transactions by transferring funds to a virtual account, instead of using cards.

#### Settlement

The transfer of collected funds from Paycashless into your business’s payout account. This typically happens within a configured settlement schedule.

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## Integration Terms

#### Webhook

A real-time notification sent to your server when certain events occur (e.g., payment received, settlement completed). You’ll pass a callback URL to receive these.

#### Callback URL

The endpoint on your system where Paycashless sends webhook events. It must be accessible over HTTPS.

#### Sandbox Environment

A testing environment with mock data and test keys. Use it to simulate real-world scenarios safely before going live.

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## Checkout

#### Checkout Widget

An embeddable payment UI for websites and apps. Fully brandable and supports “Pay with Transfer” out of the box.