Most German rental and sale inquiries start on a small number of portals, ImmoScout24 first among them, with Immowelt and Kleinanzeigen carrying most of what is left. Below that sit dozens of smaller, regional and niche portals that any given landlord may or may not need, depending on the asset and the market. The practical question is not how many portals exist, it is how many of them you can actually reach without building a bespoke connector for each one.
OpenImmo is the standard most of that traffic already speaks
OpenImmo is the XML exchange format the German portal market settled on, and OpenImmo vs the ImmoScout24 API covers the mechanics in full. The short version for this piece: any portal built to accept an OpenImmo feed can take a listing without a custom integration written specifically for it, which is how a single export reaches Immowelt, Kleinanzeigen and a good part of the long tail underneath them at the same time.
ImmoScout24 gets its own API for a reason
ImmoScout24 is large enough, and central enough to how German property search actually works, that REPM connects to it through a dedicated API rather than relying on OpenImmo alone: publish, update and withdraw a listing directly, with inquiries routed back rather than batched. The integrations page has the specifics. Everything else in this piece is about the portals below that one.
Where a fixed-connector platform still wins
OpenImmo export is broad, but it is not the same as maintaining 150 individual portal connectors the way onOffice does, and it is worth saying so plainly rather than pretending the gap does not exist. If a specific regional or niche portal needs a fixed interface rather than an OpenImmo feed on day one, onOffice is ahead there today. The fuller feature-by-feature picture, including where that gap does and does not matter, is in REPM vs onOffice.
What happens after someone clicks
A syndicated listing is only half the job. When an inquiry comes back from Immowelt, Kleinanzeigen or ImmoScout24, it lands on the same property record the listing came from, not a separate CRM inbox that has to be manually matched back to the unit later. That matters more at volume than the portal count does: a landlord running twenty units across four portals generates a lot of inbound messages, and the cost of losing track of which listing a message belongs to is higher than the cost of not being on the twelfth portal down the list.
See your own listings syndicate. Start a free REPM Lite trial at app.repm.cloud and publish a unit to see where the inquiry lands.
FAQ
Does REPM connect directly to Immowelt and Kleinanzeigen?
Through OpenImmo export rather than a bespoke connector for each. Any portal that accepts an OpenImmo feed, which includes Immowelt, Kleinanzeigen and much of the long tail below them, is reachable this way.
What is the difference between OpenImmo and the ImmoScout24 API?
OpenImmo is a shared XML export format many portals accept; the ImmoScout24 API is a dedicated, direct integration specific to that one portal. OpenImmo vs the ImmoScout24 API covers the practical difference in full.
Does REPM reach as many portals as onOffice?
Not in fixed-connector count. onOffice maintains more than 150 dedicated portal connectors, which is a real advantage for specific regional or niche portals on day one. REPM reaches the broader market through OpenImmo plus a first-class ImmoScout24 API. REPM vs onOffice has the full comparison.
Where do portal inquiries end up?
On the same property record the listing was published from, so a message from any portal is already attached to the correct unit rather than sitting in a separate inbox waiting to be matched up.