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Fair Use Policy – Onroerend Erfgoed APIs

Last updated: 15 September 2026

Scope​

This Fair Use Policy applies to all public APIs offered by Onroerend Erfgoed (the Flanders Heritage Agency) via developers.onroerenderfgoed.be and the underlying API domains (e.g. inventaris.onroerenderfgoed.be/api_doc). By using these APIs you agree to this policy.

Open access, no registration​

Our public APIs are freely accessible without an API key or registration. This open access is a service we provide in the interest of transparency and reuse of public-sector data, and it assumes responsible use by everyone who relies on it.

Reasonable use​

  • Match the volume and frequency of your requests to what your application actually needs. Avoid unnecessary repeated requests (e.g. high-frequency polling) where periodic or cached access would do.
  • Cache results on your side where possible instead of repeatedly requesting the same data.
  • Design your application to handle temporary unavailability or errors gracefully (e.g. retry with backoff rather than retrying immediately).
  • We do not currently enforce a fixed requests-per-minute limit, but we reserve the right to throttle or temporarily block traffic that degrades the service for other users.

Not permitted​

  • Using API traffic to overload or disrupt Onroerend Erfgoed's infrastructure (e.g. through automated attacks or unreasonably high parallel load).
  • Attempting to circumvent security measures, or seeking access to data or systems not explicitly exposed through the API.
  • Using the APIs for unlawful purposes, or in a way that damages the reputation of Onroerend Erfgoed or the Flemish government.
  • Falsely presenting an application as an official Onroerend Erfgoed product, unless explicitly agreed.

Data licensing​

Data exposed through our APIs is subject to the license terms stated per dataset or API (e.g. the Flemish "Modellicentie Gratis Hergebruik" or a comparable open license). Check the specific API's licensing information before reusing, publishing, or processing the data.

Availability​

We aim to keep the APIs available and performant, but we do not currently offer a guaranteed uptime (SLA) for the public APIs. Maintenance, changes, and breaking changes are announced via the changelog on this portal — we recommend subscribing if you're building a production integration on our APIs.

Changes to this policy​

We may update this policy from time to time. Material changes will be announced via the portal's changelog.

Enforcement​

In case of misuse or violation of this policy, we may, at our discretion and without prior notice in serious cases, limit or block API access for the traffic involved.

Contact​

Questions about this policy, or want to report suspected abuse? Contact us at ict@onroerenderfgoed.be.