Security
OAuth2, JWT tokens, API keys, IP whitelisting and encrypted connections. Your data is protected against unauthorised access.
Schedule a call APIs That Seamlessly Connect Your Systems
Robust REST APIs that connect your CRM, ERP, webshop, app and external platforms. Secure, fast and built to scale to millions of requests.
System Integration Through Powerful APIs
No more manual data entry — your systems share data automatically through a well-built API.
Organisations work with dozens of systems: a CRM, ERP, webshop, accounting package, inventory management and external platforms. Without proper connections, this leads to duplicate data, manual re-typing and errors that cost time and money. A well-designed API solves this problem structurally.
We build REST APIs that seamlessly connect your systems. Whether it is linking your webshop to your ERP, exposing data for a mobile app or integrating an external platform — we deliver APIs that perform reliably, are secure and easy for other developers to use.
Our APIs are built according to modern standards. OpenAPI documentation, versioning, rate limiting, authentication via OAuth2 or API keys and comprehensive logging. You get not just a working API, but a professional product ready for years of use.
- REST APIs following OpenAPI specification
- Secure authentication with OAuth2, JWT or API keys
- Comprehensive API documentation for developers
- Rate limiting and monitoring for stable performance
- Scalable from hundreds to millions of requests per day
Why Invest In Professional API Development
The operational benefits of well-built system connections.
Many organisations start with simple connections — a script that transfers data, a manual export or a standard integration from a marketplace. These solutions work for a while, but do not scale. When a system is updated, they break, there is no documentation and nobody knows how they work. Dependency on one person who built it once is a serious risk.
Professional API development solves this. A well-documented API with versioning ensures connections remain reliable, even when systems are updated. Developers can integrate on their own without intervention from your IT department. And monitoring provides insight into usage, performance and potential issues before they have an impact.
Moreover, a professional API makes your organisation more flexible. Adding new systems? Building a mobile app? Opening a new sales channel? With a solid API foundation, it is all possible without having to overhaul your entire infrastructure.
- Reliable connections that do not break during system updates
- Developer self-sufficiency through good documentation
- Monitoring and alerts for proactive management
- Flexibility to add new systems and channels
- Elimination of dependency on individual developers
What Sets Our APIs Apart
Technical quality and thoughtful design at every layer.
High Performance
Optimised for speed with caching, connection pooling and efficient queries. Response times under 100ms for most endpoints.
Schedule a call API Documentation
Full OpenAPI/Swagger documentation with examples, error codes and test environment. Developers can start integrating immediately.
Schedule a call Monitoring & Logging
Real-time insight into API usage, response times and error rates. Alerts on deviations so issues are resolved quickly.
Schedule a call Versioning
API versions ensure existing integrations do not break during updates. Backward compatibility is guaranteed as standard.
Schedule a call Rate Limiting
Protection against overload with smart rate limiting. Configurable per client or per endpoint for fair usage.
Schedule a call APIs For Every Integration
We build API solutions for a wide range of integration challenges.
ERP & Accounting
Connections with Exact, Twinfield, AFAS, Visma and other ERP systems. Real-time synchronisation of orders, customers and inventory.
Schedule a call E-commerce & Webshops
APIs for product data, order processing, inventory management and shipping integrations. Connections with Mollie, Sendcloud and other platforms.
Schedule a call Mobile Applications
Backend APIs for mobile apps with authentication, push notifications and real-time data. Optimised for mobile networks.
Schedule a call CRM & Customer Portals
API layer for customer portals and CRM systems. Customer data, order statuses, documents and tickets exposed through a unified interface.
Schedule a call Logistics & Tracking
Connections with carriers, track-and-trace systems and inventory platforms. Real-time shipping statuses and delivery information.
Schedule a call Third Parties & Platforms
Integration with external services such as payment providers, email platforms, accounting systems and industry-specific solutions.
Schedule a call How We Build an API
A proven process from analysis to production — focused on reliability and scalability.
01
Introduction & Analysis
We discuss which systems need to be connected, what data will be exchanged and what the desired performance requirements are. We map the integration landscape.
02
API Design
We design the API structure with endpoints, data models, authentication and error handling. You receive an API specification before we start building.
03
Development
Our development team builds the API with modern technologies like Python/FastAPI or PHP. Every endpoint is tested for correctness, speed and security.
04
Documentation
We deliver full OpenAPI documentation with examples, error codes and a test environment. Developers can start integrating immediately without back-and-forth.
05
Integration & Testing
We connect the API to your existing systems and test the full data flow. Load testing verifies the API performs under expected and peak loads.
06
Monitoring & Launch
We set up monitoring with alerts on deviations and bring the API live in production. You have real-time insight into usage and performance.
07
Aftercare & Further Development
Even after launch, we remain available for maintenance, new endpoints and optimisation. We monitor performance and advise on improvements.
Why Choose Speedy Systems
We combine API expertise with broad integration knowledge.
Speedy Systems is not a standard web agency. We are a software company that builds APIs with the same technical depth as our custom software. That means: clean code, thoughtful architecture and solutions that scale to millions of requests per day.
Our team has extensive experience with system integration in complex environments. We have built APIs for wholesalers with thousands of SKUs, healthcare institutions with sensitive patient data and e-commerce platforms with peak loads during promotions. You benefit from this experience without having to reinvent the wheel.
We believe in long-term relationships. Many of our clients have been working with us for years — not because they are tied to a contract, but because they value the quality and reliability we deliver.
- Deep experience with REST API architecture and integrations
- Modern tech stack with Python/FastAPI and PHP
- Transparent communication with dedicated contact persons
- Comprehensive testing including load and security tests
- Ongoing support and maintenance available
- Scalable architecture that grows with your organisation
Frequently Asked Questions About API Development
Answers to the questions we receive most often.
What is a REST API?
A REST API is a standardised way for systems to communicate with each other via the HTTP protocol. It is the most widely used form of system integration in the world and forms the backbone of virtually all modern connections between software, apps and platforms.
How long does it take to develop an API?
A standard API with 10 to 20 endpoints is delivered within 4 to 8 weeks. More complex APIs with extensive authentication, real-time synchronisation or multiple system connections take 10 to 16 weeks. The exact timeline depends on the number of integrations and the complexity of the data flows.
What does API development cost?
API development starts from €5,000 for a basic integration with limited endpoints. Extensive APIs with multiple system connections, authentication and monitoring start from €12,500. We always provide a custom quote after a no-obligation conversation.
Can my existing ERP or CRM be connected?
Yes. We build connections with all common systems such as Exact, Twinfield, AFAS, Visma, Salesforce and SAP Business One. Integrations with custom systems, databases and external platforms are also available.
How is the API secured?
Our APIs are secured with OAuth2 or JWT authentication, encrypted connections (TLS), IP whitelisting and rate limiting. Every request is validated and logged. We follow the latest security standards to prevent unauthorised access.
Will I receive documentation with the API?
Absolutely. We provide full OpenAPI/Swagger documentation as standard, including example requests, error codes, authentication instructions and a test environment. Developers can start integrating immediately without back-and-forth with your internal team.
What if the number of requests increases?
Our APIs are designed to scale. With caching, connection pooling and efficient database queries, they perform well even with increasing traffic. Monitoring provides insight into usage, so we can proactively scale up when needed.
Do you also offer maintenance for APIs?
Yes. We offer maintenance contracts including monitoring, security updates, performance optimisation and new endpoints. We proactively monitor performance and respond to changes in connected systems.
Related Services
Services often combined with API development.
Ready to Have APIs Developed?
Let's discuss how we can connect your systems. Receive a custom proposal with no obligation.