API-Entwicklung

Development of RESTful APIs and GraphQL interfaces to connect different systems. We build flexible, documented interfaces for your applications.

Overview

Our API development connects applications, services and third-party providers securely, at scale and with good performance. We build both REST and GraphQL interfaces, focusing on clear specification, documentation, security and long-term maintainability. The goal is APIs that extend flexibly, integrate easily and are ready for high load.

Benefits

System integration — well-structured APIs connect internal and external systems seamlessly and to a standard.

Scalability — our APIs are designed to handle heavy load and large data volumes with good performance.

Built to last — versioning and clean API design make later extensions possible without breaking changes.

Security and control — authentication mechanisms such as OAuth2, JWT and rate limiting protect your APIs reliably.

Developer-friendly — automatic Swagger/OpenAPI documentation lets internal and external teams integrate quickly.

Standardisation — consistent API conventions across every endpoint for uniform integration.

Our Process

Requirements Analysis

Together we define the systems to be integrated, interfaces and business processes.

API Design

We design a clean and documented API schema – REST or GraphQL – tailored to your use cases.

Implementation

The API is developed with robust frameworks like Express or NestJS and secured with tests.

Documentation

Automatically generated or manual API documentation enables quick integration by developers.

Tests & Monitoring

We test the interfaces automatically and use runtime monitoring to track availability and errors.

Frequently Asked Questions

What is the difference between REST and GraphQL?

REST is resource-oriented — each URL represents a resource. Simple to understand and cache. GraphQL is query-oriented — the client defines exactly what data it needs, avoiding over- and under-fetching. We recommend REST for simple CRUD APIs and public APIs, GraphQL for complex, connected data and mobile apps.

How is my API secured?

We implement multiple security layers: JWT bearer tokens for stateless auth, OAuth2 for delegated authorization, API keys for internal service communication, rate limiting against DDoS/brute-force, HTTPS-only, input validation and CORS configuration.

Do you also offer integration with third-party systems?

Yes, third-party integration is an important part of our API work: payment providers (Stripe, PayPal), CRM systems (Salesforce, HubSpot), ERP systems, email services (SendGrid, Mailgun), cloud storage (AWS S3) and many more.

How do you document the interfaces?

We use OpenAPI 3.x (Swagger) for complete API documentation. In NestJS, endpoints are documented with decorators — Swagger UI generates automatically. We also create Postman collections for manual testing. Versioning via URL paths ensures backward compatibility.

Interested?

Interested in our API-Entwicklung service? Contact us for a free initial consultation.

Get in touch

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