API Integration

Systems that talk to each other

Running systems in isolation means paying twice: once for the software and once for the manual work that bridges the gaps. API integration connects platforms, tools, and processes into a landscape that works as one. We develop interfaces for websites, web apps, and digital platforms — stable, documented, and maintainable.

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The problem

Systems side by side cost more than systems working together

As a company grows, so does its system landscape. At some point there's a CRM, an ERP, a shop system, and a platform — and none of them talks to the others.

Data is transferred between systems manually
‍because no interface exists.
The last system update broke an existing connection
‍and nobody noticed right away.
A new tool needs to be connected
‍but the current provider doesn't know the required APIs.

Our approach

Connections that hold

We develop API integrations and interfaces for existing systems as well as new platforms. Whether a single service needs connecting or a more complex system landscape needs linking — stability, documentation, and maintainability are the focus from day one.

Interface Development

Clean REST and GraphQL interfaces that integrate into existing architectures without destabilizing them.

Third-Party Integration

Payment providers, shipping providers, CRM and ERP systems, AI APIs: we connect what's needed.

Data Synchronization

Data flows between systems automatically instead of being maintained by hand — consistent and traceable.

Maintenance & Monitoring

Interfaces need care. We set up monitoring and react before a broken API disrupts operations.

Case Study

Challenge

Valiair had to be first to market in the new FAA regulatory segment — with digital processing, worldwide shipping, and automatic payment handling from day one.

Approach

We integrated the UPS API for international shipping options, Stripe for subscription payments, and an FAA database connection for the registration logic into a custom-built web app.

Results

100% digital processing from launch day, no manual rework — and market leadership in the niche.

How we work.

How the collaboration works

Fixed phases, one dedicated contact, and regular feedback loops. Knowledge about the existing system landscape flows directly into architecture decisions — integrations are built to fit reality, not an ideal world.

The hard facts

Flexible monthly hours model (cancellable monthly) or fixed-price project. Full handover guaranteed: code, documentation, and access go to the client. On request, we take over monitoring and ongoing maintenance of the interfaces afterwards.

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Why companies with complex system landscapes choose Webnique for API integration

Most agencies build interfaces as an afterthought — a necessary evil at the end of a project. We factor API integration in from the start, because a platform without stable connections only half works. Our experience from custom development and web app projects means the integrations fit the architecture instead of working against it. And because we have strategy, design, and development under one roof, clients never have to choose between the digital-agency part and the engineering part.

In Detail

From interface analysis to ongoing operations

01.

Requirements Analysis & System Overview

First understand what needs to be connected.

Which systems exist, which APIs are available, which data needs to flow? These questions are answered at the start, not during implementation. A complete system overview prevents dependencies from surfacing only when the first problem hits.

01.

API Concept & Architecture

The data flows, before the code is written.

We document how systems should communicate: endpoints, data models, authentication methods, error behavior. This specification is the foundation for an implementation that stays maintainable.

01.

Interface Development

Clean interface programming for long-term stability.

Whether REST, GraphQL, or webhook-based — we implement to documented standards. The code is written so that another team can read and adapt it later.

01.

Third-Party Integration

External services, cleanly connected.

Payment providers, shipping APIs, ERP systems, AI services: we know the common APIs and their quirks. Where an integration isn't trivial, we document the specifics explicitly.

01.

Authentication & Security

API access that stays under control.

OAuth, API keys, token management, and rate limits are implemented correctly from the start. An insecure interface isn't a cost advantage — it's a risk.

01.

Data Synchronization & Error Handling

Even when something goes wrong, the data stays clean.

We build in retry logic, error logs, and fallback mechanisms. Interfaces that fail silently create inconsistent data — the ones that fail loudly are manageable.

01.

Testing & Quality Assurance

Tested under conditions that resemble reality.

Automated tests check the interfaces under load and at boundary values. Problems are found before they show up in production.

01.

Monitoring & Alerting

Interfaces that report when something is off.

We set up monitoring for all production APIs. If an interface fails or latency exceeds a threshold, an alert goes out — before customers or users notice.

01.

Documentation & Handover

What was built is fully described.

Every interface is documented: endpoints, parameters, example requests, error types. The documentation transfers to the client at handover.

01.

Operations & Further Development

System landscapes change — interfaces have to keep up.

On request, we take over ongoing maintenance and adapt integrations when third-party systems change or new services are added. A team that knows the architecture reacts faster than one starting from scratch.

What needs connecting — and how — we'll clarify in 30 minutes.

An initial conversation narrows down which connections make sense and where the biggest lever lies. Concrete and without obligation.

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Frequently asked questions

FAQs

What does an API integration cost?

The effort depends on the number of systems, the quality of the existing APIs, and the complexity of the data flows. Simple integrations are implemented within a few days; more complex system integrations can take several weeks. The scope is narrowed down concretely in the discovery call.

What is the difference between API integration and API development?

API development means building your own interface — developing an endpoint through which other systems can access a platform. API integration means connecting an existing external API. In practice, the two often go hand in hand.

What is interface development?

Interface development is the technical process of connecting two or more systems so that data is exchanged between them automatically. It covers the concept, the implementation of the connection, and error handling in ongoing operations.

Which APIs can be integrated?

In principle, any API with a documented interface. Typical examples are payment providers (Stripe, PayPal), shipping APIs (UPS, DHL), CRM and ERP systems, AI services (OpenAI, Anthropic), and industry-specific data sources. Even poorly documented or proprietary APIs can be connected in most cases.

What happens when an external API changes?

API changes are inevitable — providers version, deprecate, or modify endpoints. With an ongoing maintenance contract, such changes are monitored and adjustments implemented promptly. Without maintenance, we recommend at least a monitoring setup that flags outages immediately.

Can an existing API integration be taken over or extended?

Yes. A short analysis of the existing implementation clarifies its condition, risks, and sensible next steps. In many cases, an existing integration can be stabilized or extended without rebuilding it from scratch.

How long does an interface integration take?

A simple third-party integration is production-ready within a few days. More complex system integrations with multiple data flows, dedicated error handling, and monitoring typically take two to eight weeks.

Can an AI API be integrated?

Yes. Integrating AI services such as OpenAI or other LLM providers technically works through the same mechanisms as any other API integration — with the difference that prompt engineering, context management, and response processing add extra requirements. If you want to embed AI features directly into your product, you'll find more on our AI Integration page.

For even more impact

More services.

AI Integration

Embed AI services and LLMs directly into platforms and web apps.

Web App Development

When the API integration is part of a larger application.

Client Portal Development

Connect platforms with third-party providers.