+### Language of results
+
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| accept-language | browser language string | content of "Accept-Language" HTTP header |
+
+Preferred language order for showing search results. This may either be
+a simple comma-separated list of language codes or have the same format
+as the ["Accept-Language" HTTP header](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Language).
+
+!!! tip
+ First-time users of Nominatim tend to be confused that they get different
+ results when using Nominatim in the browser versus in a command-line tool
+ like wget or curl. The command-line tools
+ usually don't send any Accept-Language header, prompting Nominatim
+ to show results in the local language. Browsers on the contratry always
+ send the currently chosen browser language.
+
+### Result restriction
+
+There are two ways to influence the results. *Filters* exclude certain
+kinds of results completely. *Boost parameters* only change the order of the
+results and thus give a preference to some results over others.
+
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| countrycodes | comma-separated list of country codes | _unset_ |
+
+Filer that limits the search results to one or more countries.
+The country code must be the
+[ISO 3166-1alpha2](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) code
+of the country, e.g. `gb` for the United Kingdom, `de` for Germany.
+
+Each place in Nominatim is assigned to one country code based
+on OSM country boundaries. In rare cases a place may not be in any country
+at all, for example, when it is in international waters. These places are
+also excluded when the filter is set.
+
+!!! Note
+ This parameter should not be confused with the 'country' parameter of
+ the structured query. The 'country' parameter contains a search term
+ and will be handled with some fuzziness. The `countrycodes` parameter
+ is a hard filter and as such should be prefered. Having both parameters
+ in the same query will work. If the parameters contradict each other,
+ the search will come up empty.
+
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| layer | comma-separated list of: `address`, `poi`, `railway`, `natural`, `manmade` | _unset_ (no restriction) |
+
+The layer filter allows to select places by themes.
+
+The `address` layer contains all places that make up an address:
+address points with house numbers, streets, inhabited places (suburbs, villages,
+cities, states tec.) and administrative boundaries.
+
+The `poi` layer selects all point of interest. This includes classic POIs like
+restaurants, shops, hotels but also less obvious features like recycling bins,
+guideposts or benches.
+
+The `railway` layer includes railway infrastructure like tracks.
+Note that in Nominatim's standard configuration, only very few railway
+features are imported into the database.
+
+The `natural` layer collects feautures like rivers, lakes and mountains while
+the `manmade` layer functions as a catch-all for features not covered by the
+other layers.
+
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| featureType | one of: `country`, `state`, `city`, `settlement` | _unset_ |
+
+The featureType allows to have a more fine-grained selection for places
+from the address layer. Results can be restricted to places that make up
+the 'state', 'country' or 'city' part of an address. A featureType of
+settlement selects any human inhabited feature from 'state' down to
+'neighbourhood'.
+
+When featureType ist set, then results are automatically restricted
+to the address layer (see above).
+
+!!! tip
+ Instead of using the featureType filters `country`, `state` or `city`,
+ you can also use a structured query without the finer-grained parameters
+ amenity or street.
+
+| Parameter | Value | Default |
+|-----------| ----- | ------- |
+| exclude_place_ids | comma-separeted list of place ids |