Source: Post by Paul Norman on community.osm.org, information copied below.
On Sunday January 22nd 2023 between 10:00 and 15:00 UTC/GMT the API database servers will be unavailable due to maintenance. You can see this in your local time zone at Event Time Announcer - OpenStreetMap API Maintenance
We are planning to upgrade the software which runs the main OpenStreetMap database. Unfortunately, we cannot do this without some downtime.
The following services WILL be affected:
- www.openstreetmap.org web site WILL NOT allow edits,
- API will NOT allow map editing (using iD, JOSM, etc), and
- replication updates will be paused (minutely updates and changeset replication).
We expect that the database upgrade will not take the full duration, and we will try as far as possible to keep the API available in read-only mode, but the API may be briefly unavailable.
At times you may be unable to login to services which requires openstreetmap.org authentication (e.g. community, forum, and help)
Other OpenStreetMap provided services should not be affected except for login - all of the following are expected to function normally:
- Map viewing on www.openstreetmap.org
- nominatim (search)
- standard tile layer
- mailing lists
- Distribution of planet file and existing diffs
Services not run by the OSMF will not be impacted, except there will be no updates from OSM.
Technical details are at Plan API database PostgreSQL upgrade · Issue #548 · openstreetmap/operations · GitHub