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:

  1. Register for access through the PDOK portal (Dutch national geo-portal)

  2. Read the documentation to understand available endpoints

  3. Start with simple queries to test the connection

  4. 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.