BAG
What Is the BAG API?
The BAG API gives access to the Netherlands' official database of addresses and buildings. BAG stands for "Basisregistratie Adressen en Gebouwen" (Basic Registration of Addresses and Buildings). It's maintained by the Dutch Kadaster (Land Registry Office) and provides reliable information about every address and building in the Netherlands.
What Data Does BAG Contain?
The BAG includes several types of information:
Buildings: Location, purpose, construction year, and status
Addresses: House numbers, street names, postal codes, and cities
Apartments: Individual units within buildings
Houseboats: Registered moorings for water residences
Mobile home locations: Official stands for mobile homes
How to Access BAG Data
The BAG API offers several ways to access the data:
REST API: The modern, easy-to-use interface for most developers
Geographic services: Access to map-based building and address data
Downloads: Complete datasets for offline use
Search functions: Find addresses and buildings using various criteria
Who Uses the BAG API?
Government Organizations
Municipalities for address verification
Emergency services for accurate locations
Urban planners for development projects
Businesses
Delivery companies for address validation
Real estate websites for property information
Insurance companies for building data
Developers
Creating mapping applications
Building address validation tools
Developing location-based services
Getting Started
To use the BAG API:
Register for access through the PDOK portal (Dutch national geo-portal)
Read the documentation to understand available endpoints
Start with simple queries to test the connection
Implement error handling for your application
Key Benefits
Official data: Government-guaranteed accurate information
Complete coverage: Includes every address and building in the Netherlands
Regular updates: Data is updated daily as changes occur
Open data: Available for public use with minimal restrictions
Standardized format: Consistent data structure across the country
Practical Tips
Cache results to reduce unnecessary API calls
Only request the data you need to improve performance
Provide proper attribution to Kadaster as the data source
Consider using Dutch coordinates (RD) for more precise locations
The BAG API is an essential tool for anyone working with Dutch address or building data, offering reliable information from the official government source.
