Due to historical developments, numerous data formats exist for the exchange of data between the various real estate brokerage software vendors and online real estate portals. Some companies are already considering a standard and have developed initial ideas. Attempts to achieve standardization through central databases have remained unsatisfactory. In many industries worldwide, the XML language has proven to be an effective solution.
In November 2001, the first version of the standard was adopted, and the first implementations of the XML interface began. The initial working title combined the terms “Immo” with the underlying technology “XML.”
In April 2002, it was decided to establish a supporting association for the continued maintenance and development of the standard. Since early 2003, the initiative has been operating under the name “OpenImmo.” To date, OpenImmo is used in over 10 countries. The XML specification has been downloaded over 15,000 times.
The page gives a short info about OpenImmo in several Languages
OpenImmo e.V. is supported by approximately 40 supporting members.
These members come from the real estate industry and include CRM providers, portals, and service providers.
Many of the founding members from 2002 are still active today. In addition to companies from Germany, members from Austria, Switzerland, and France (AVIV Group) have also joined.
Here you will find the complete list of supporting members
More details on the organization’s founding, its goals, and the benefits of membership
OpenImmo e.V. has introduced the option of voluntary licensing for the XML version.
Licensees receive additional information and the opportunity to participate more actively.
A different licensing model will be in place starting in 2027 with the availability of the REST API. Existing licensees will retain their status.
Here you will find the list of licensees
At the time OpenImmo was launched, the XML description language—with its definition in the XML schema—represented the state of the art.
The XML version contained approximately 250 attributes in the elements and attributes typical of XML.
In most cases, images and other media files were zipped together with the XML description.
These were then transferred via FTP from the sender to the recipient.
The descriptions of the elements are in German. However, OpenImmo is used in many countries. In Austria, there is a dedicated “UserGroup” that addresses specific requirements.
As the REST API grew in popularity, there was a growing demand for a true “interface.” Some time ago, the OpenImmo Group began planning the new, incompatible Version 2.x. The data structures were revised, and the number of elements was reduced and updated. Country-specific sections were added to accommodate the growing international adoption. The first beta version of OpenImmo 2.x was completed at the end of 2021.
- The data structure is described in English
- The data format is now JSON
- Data is transmitted via a REST API
- Data and the REST API are now described in OpenAPI 3.0
- Data types and formats have been added
- Recommendations and instructions for data processing have been added
- Country-specific sections have been added in areas such as price, square footage, features, etc.
The final version 2.0 is expected to be released at the end of 2026.
Please send inquiries by email to support - at - openimmo.de
Please note that OpenImmo e.V. does not have its own support department. Likewise, telephone support is not available. As a CRM or portal provider, please download the information about the interface from the website or via the link to the OpenImmo 2.0 REST API.
An FAQ for the REST API is currently in the works.
Information about OpenImmo e.V.
OpenImmo e.V., an association promoting data exchange in the real estate industry
Mailing Address, Office: Kamillenweg 24, 50858 Cologne
Phone: 0221-9520559
The phone number is included here solely for the sake of completeness in the legal notice.
Please direct all questions regarding OpenImmo via email to the office.
office - at - openimmo.de
This is the only way we can provide you with a qualified response