Because this question comes up again and again, I would like to document the answer here in a little more detail.
A garden house that was added two months ago to the OSM database is not displayed on a map at certain zoom levels, even though the underlying map data should actually be up to date. In my example, the problem was reported both in the GitHub repository of the map and in the GitHub repository of the German map style.
However, the map at karte.openstreetmap.de requests the tiles in exactly the same way as any other map that uses tiles from tile.openstreetmap.de: it retrieves them from the tile server tile.openstreetmap.de.
So, if you can rule out problems such as a local browser or map cache, troubleshooting continues at tile.openstreetmap.de.
New OpenStreetMap data should ideally become visible on tile.openstreetmap.de within a few minutes. After all, one of the most important tasks of the German tile servers is to show OpenStreetMap contributors as quickly as possible whether their changes have correctly arrived in the database.
This happens in two steps.
Keeping OSM data up to date
Database
The databases of the German tile servers are continuously updated via osm2pgsql using the latest OpenStreetMap data.
The current state of the database update can be seen directly below the map.
The displayed time is UTC. In Germany, this means that during daylight saving time the displayed time is two hours behind local time, and during standard time it is one hour behind.
It is also worth knowing that, for redundancy reasons, two servers are behind tile.openstreetmap.de. Currently these are Cassini and Bonne. The website indicates in its heading which server you have reached.
This is important when troubleshooting: a problem can occur on only one of the two servers while everything is already displayed correctly on the other. This can be particularly confusing.
Prerendering
Even if the database is up to date, this does not necessarily mean that every map tile being served contains the latest data.
The reason is so-called prerendering: map tiles are not rendered from scratch every time they are requested. Once a tile has been rendered, it is reused until a database update determines that it needs to be rendered again because of a change.
An outdated tile is not deleted immediately. Instead, it is marked as dirty.
When a tile is marked as “dirty,” a technically very simple but efficient trick takes place: the system does not delete the tile; instead, it changed its age on the server’s filesystem. When a tile is generated normally, the server stores it with the current timestamp. A tile marked as dirty, however, suddenly has the file date January 1, 1970, while remaining in the same directory. When a user scrolls to exactly this region in the browser, the following happens:
[Browser requests tile]
│
▼
[mod_tile checks file]
│
├──► Is the file date newer than the last DB update? ──► [Serve immediately]
│
└──► Is the file date older (e.g. Jan. 1, 1970)? ──────► [Tile is DIRTY!]
│
▼
[Send render command to Tirex]
This has an important advantage: if the servers are heavily loaded, they can continue to serve existing, even if potentially outdated, tiles.
This keeps the map display as performant as possible even under heavy server load and avoids unnecessary blank areas.
For most users, this is a sensible compromise. Sometimes, however, a mapper needs to see the current state of a particular location immediately.
Requesting new OpenStreetMap.de tiles
When I read the issue linked above, I therefore looked at the affected location directly on both tile servers:
The shed was not visible on cassini:
On bonne, however, it was already visible:
This is not ideal. As described above, however, it is a deliberate compromise. If the servers are heavily loaded, not every change can be rendered immediately on every server. Otherwise, significantly more computing resources would be required, or one would have to accept that the map becomes slower more frequently or that areas that have not yet been rendered appear as blank areas.
Sometimes, however, a mapper needs to see the current state of a particular location. To do this, they can request more infos of the corresponding tile via the context menu on tile.openstreetmap.de.
Update tile
When viewing a particular tile on tile.openstreetmap.de, you can open a context menu with the right mouse button. It provides an option to retrieve further information about the tile.
Clicking Kachelinfos shows detailed information about the tile:
The tile on Cassini was rendered in May:
https://cassini.openstreetmap.de/19/275933/172159.png/status: Tile is clean. Last rendered at Mon May 11 14:10:07 2026. Last accessed at Fri Oct 02 18:14:45 2026. Stored in file:///var/cache/tirex/tiles/osmde/19/66/58/80/215/136.meta (Dates might not be accurate. Rendering time might be reset to an old date for tile expiry. Access times might not be updated on all file systems).
The tile is therefore indeed still based on an old data set.
The behavior (Do not regenerate it immediately if the server is under heavy load.
) can also be understood from the source code of mod_tile.
Conclusion
On the German OpenStreetMap tile servers, mappers have the option of requesting infos for a specific tile.
The OpenStreetMap data is continuously imported into the database.
Changes invalidate the affected tiles and mark them as dirty.
When the servers are heavily loaded, older, already existing tiles continue to be served.
So if a change is not yet visible, this does not necessarily mean that the OpenStreetMap data has not yet been updated or that there is another problem. It may simply be that the server is currently busy.
German see https://astrid-guenther.de/digitaleKartenAktualisieren/
OpenStreetMap Blogs
OpenStreetMap Blog
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