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Basics

Interface / Integration

An interface (API/interface) defines how two software systems communicate. Integration is the process of connecting those systems and exchanging data automatically.

In modern IT no system works in isolation. ERP talks to the online shop, CRM syncs with the email tool, and accounting receives invoice data automatically. Interfaces are the invisible bridges that make this data exchange possible. Without well-designed integrations you get data silos, duplicate data entry and error-prone processes.

What is Interface / Integration?

An interface (in English: interface or API – Application Programming Interface) is a defined communication layer between two software components. It specifies which data is exchanged in which format, which operations are possible and how authentication works. Integration is the process of connecting different systems via interfaces so that data flows automatically in real time or on a schedule. Modern interfaces are mostly REST APIs or GraphQL and use JSON. For complex scenarios, middleware or Enterprise Service Buses (ESB) are used.

How does Interface / Integration work?

System A sends structured data to System B’s interface via HTTP (e.g. GET, POST). System B processes the request, performs the operation and returns a response. Authentication typically uses API keys, OAuth tokens or certificates. For real-time data, webhooks or WebSockets send notifications when something changes. Middleware orchestrates complex integrations, transforms data formats and monitors exchange.

Practical Examples

1

ERP–shop integration: Order and stock data are synced in real time between ERP and online shop so stock levels are always correct.

2

CRM–email sync: Every email and customer contact is recorded in the CRM automatically so sales staff do not have to create entries manually.

3

Payment processing: A shop integrates Stripe or PayPal via their APIs to process payments and post transactions automatically.

4

HR system integration: New employees are created in the HR tool and automatically provisioned in Active Directory, email and internal tools.

Typical Use Cases

Automating business processes: Data flows between ERP, CRM, accounting and logistics without manual input

E-commerce: Real-time sync of product data, orders and stock across channels

Data consolidation: Combining information from multiple sources for BI and reporting

Partner integration: Automated exchange with suppliers, logistics or authorities

SaaS integration: Connecting cloud tools to existing on-premise systems

Advantages and Disadvantages

Advantages

  • No duplicate manual entry and fewer errors
  • Real-time data across all connected systems
  • Faster processes through automated exchange
  • Better decisions from consolidated, up-to-date data
  • Flexibility: new systems can be added via standard interfaces

Disadvantages

  • Initial complexity: Different systems have different data models and formats
  • Dependency on third-party APIs; their changes can cause breaking changes
  • Security: Every interface is a potential attack surface and must be secured
  • Maintenance: Integrations must be updated and tested when systems change

Frequently Asked Questions about Interface / Integration

What is the difference between API and interface?

Strictly, an API (Application Programming Interface) is one type of interface for communication between software systems. Interface is broader and can mean hardware (USB, HDMI) or user interfaces. In practice the terms are often used interchangeably in software.

How secure are API integrations?

Security depends on implementation. Best practices: OAuth 2.0 for authentication, HTTPS for transport, rate limiting against abuse, input validation against injection. Regular security reviews and API monitoring are also important.

How long does a typical system integration take?

It depends on complexity. A simple API integration (e.g. payment provider) takes 1–2 weeks. A full ERP–shop integration can take 2–4 months. Key factors are API quality, data complexity and requirements for real-time sync.

Related Terms

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What is an Interface (API)? Integration Explained