+#### NOMINATIM_SERVE_LEGACY_URLS
+
+| Summary | |
+| -------------- | --------------------------------------------------- |
+| **Description:** | Enable serving via URLs with a .php suffix |
+| **Format:** | boolean |
+| **Default:** | yes |
+| **Comment:** | Python frontend only |
+
+When enabled, then endpoints are reachable as `/<name>` as well as `/<name>.php`.
+This can be useful when you want to be backwards-compatible with previous
+versions of Nominatim.
+
+
+#### NOMINATIM_API_POOL_SIZE
+
+| Summary | |
+| -------------- | --------------------------------------------------- |
+| **Description:** | Number of parallel database connections per worker |
+| **Format:** | number |
+| **Default:** | 10 |
+| **Comment:** | Python frontend only |
+
+Sets the maximum number of database connections available for a single instance
+of Nominatim. When configuring the maximum number of connections that your
+PostgreSQL database can handle, you need at least
+`NOMINATIM_API_POOL_SIZE` * `<number of configured workers>` connections.
+For configuring the number of workers, refer to the section about
+[Deploying the Python frontend](../admin/Deployment-Python.md).
+
+#### NOMINATIM_QUERY_TIMEOUT
+
+| Summary | |
+| -------------- | --------------------------------------------------- |
+| **Description:** | Timeout for SQL queries to the database |
+| **Format:** | number (seconds) |
+| **Default:** | 10 |
+| **Comment:** | Python frontend only |
+
+When this timeout is set, then all SQL queries that run longer than the
+specified numbers of seconds will be cancelled and the user receives a
+timeout exceptions. Users of the API see a 503 HTTP error.
+
+The timeout does ont apply when using the
+[low-level DB access](../library/Low-Level-DB-Access.md)
+of the library. A timeout can be manually set, if required.
+
+
+#### NOMINATIM_REQUEST_TIMEOUT
+
+| Summary | |
+| -------------- | --------------------------------------------------- |
+| **Description:** | Timeout for search queries |
+| **Format:** | number (seconds) |
+| **Default:** | 60 |
+| **Comment:** | Python frontend only |
+
+When this timeout is set, a search query will finish sending queries
+to the database after the timeout has passed and immediately return the
+results gathered so far.
+
+Note that under high load you may observe that users receive different results
+than usual without seeing an error. This may cause some confusion.
+