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

# POS Systems

> Technical integration guide for POS providers implementing DRP to enable encrypted receipt delivery.

# POS System Integration Guide

This guide covers how POS providers integrate DRP to enable merchants to send encrypted receipts to customers.

***

### Integration Architecture

#### Plugin/Extension Model (recommended for marketplaces)

Build DRP as an optional plugin that merchants enable in your app marketplace. We provide:

* Complete plugin source code templates
* Merchant onboarding flows
* Admin dashboard for key management

#### Native Integration

Build DRP directly into your POS core for seamless merchant experience and tighter integration with receipt generation.

#### Hybrid Approach

Basic DRP support native, with advanced features (analytics, customer matching) as optional plugins.

***

### Technical Requirements

#### Receipt Generation

* Convert existing receipt format to JSON-LD schema
* Add cryptographic signing with merchant private keys
* Encrypt with customer public keys from issuer directory

#### Key Management

* Secure merchant private key storage (HSM recommended)
* Public key distribution to issuer network
* Key rotation protocols

#### Transmission

* Webhook to issuer endpoints
* Optional: batch processing for high-volume merchants
* Retry logic and delivery confirmation

Reference implementations are available for all components.

***

### Developer Resources

#### SDKs for major POS platforms

* JavaScript (web-based POS)
* Swift/Objective-C (iOS POS apps)
* Android/Kotlin (Android POS apps)
* Windows/.NET (desktop POS)

#### Testing & certification

* Sandbox environment with test issuers
* Compliance verification tools
* Certification badge for compliant implementations

#### Support

* Technical documentation
* Developer community forum
* Direct engineering consultation for high-volume integrators

***

### Licensing

DRP is free and open-source. There are no licensing fees, per-transaction costs, or revenue share requirements.

***

### Technical FAQ

<AccordionGroup>
  <Accordion title="What's the typical integration timeline?">
    Most POS systems complete full integration in 2-4 weeks of active development:

    * Week 1-2: Technical discovery and SDK integration
    * Week 3-4: Testing and certification with sandbox issuers
  </Accordion>

  <Accordion title="Do we need to host any DRP infrastructure?">
    No. DRP is stateless. You implement:

    * Receipt generation (converting your format to JSON-LD)
    * Cryptographic signing with merchant keys
    * Encryption with customer public keys
    * Webhook transmission to issuer endpoints

    All components run in your existing POS infrastructure with no additional hosting requirements.
  </Accordion>

  <Accordion title="How do we handle key management for many merchants?">
    We provide reference implementations for secure key management:

    * HSM integration for high-security merchant keys
    * Key rotation protocols and automation
    * Public key distribution to issuer network
    * Recovery procedures for lost/compromised keys

    Most POS systems treat merchant keys similarly to API keys with appropriate security controls.
  </Accordion>

  <Accordion title="What if receipt transmission fails?">
    Receipt transmission is asynchronous and non-blocking. Payment authorization completes normally. DRP includes retry logic and delivery confirmation, but transmission failures don't impact core POS functionality.
  </Accordion>

  <Accordion title="How does DRP certification work?">
    We provide:

    1. **Sandbox environment** with test issuers for development
    2. **Compliance verification tools** to validate implementations
    3. **Certification badge** for compliant POS systems
    4. **Ongoing compatibility testing** as protocol evolves

    Certification is free and demonstrates standards compliance.
  </Accordion>

  <Accordion title="What support is available during integration?">
    * Complete technical documentation and API specs
    * Reference implementations in major languages
    * Developer community forum for peer support
    * Direct engineering consultation for high-volume integrators
    * Integration testing and troubleshooting assistance
  </Accordion>

  <Accordion title="How does DRP handle international merchants and currencies?">
    DRP is currency-agnostic and supports international standards:

    * JSON-LD includes currency codes (USD, EUR, GBP, etc.)
    * Internationalized merchant identifiers
    * Multi-language receipt content support
    * Timezone-aware timestamps

    The protocol works globally with the same security and privacy guarantees.
  </Accordion>
</AccordionGroup>