diff --git a/CHANGELOG.md b/CHANGELOG.md
index c13b70a..5e1c9b3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - You can now click a button in the search bar to search (you can also still just prss enter, of course).
+- You can now filter searches by instance type.
 
 ### Changed
 
diff --git a/backend/lib/backend/api.ex b/backend/lib/backend/api.ex
index 8b3d017..7ba78b3 100644
--- a/backend/lib/backend/api.ex
+++ b/backend/lib/backend/api.ex
@@ -107,52 +107,15 @@ defmodule Backend.Api do
     end
   end
 
-  def search_instances(query, from \\ 0) do
+  def search_instances(query, filters, from \\ 0) do
     page_size = 50
 
     search_response =
-      Elasticsearch.post(Backend.Elasticsearch.Cluster, "/instances/_search", %{
-        "sort" => "_score",
-        "from" => from,
-        "size" => page_size,
-        "min_score" => 1,
-        "query" => %{
-          "bool" => %{
-            "filter" => %{
-              "term" => %{
-                "opt_out" => "false"
-              }
-            },
-            "should" => [
-              %{
-                "multi_match" => %{
-                  "query" => query,
-                  "fields" => [
-                    "description.english",
-                    "domain.english"
-                  ]
-                }
-              },
-              %{
-                "wildcard" => %{
-                  "domain.keyword" => %{
-                    "value" => query,
-                    "boost" => 100
-                  }
-                }
-              },
-              %{
-                "wildcard" => %{
-                  "domain.keyword" => %{
-                    "value" => "*#{query}*",
-                    "boost" => 50
-                  }
-                }
-              }
-            ]
-          }
-        }
-      })
+      Elasticsearch.post(
+        Backend.Elasticsearch.Cluster,
+        "/instances/_search",
+        build_es_query(query, filters, page_size, from)
+      )
 
     with {:ok, result} <- search_response do
       hits =
@@ -172,4 +135,51 @@ defmodule Backend.Api do
       }
     end
   end
+
+  defp build_es_query(query, filters, page_size, from) do
+    opt_out_filter = %{"term" => %{"opt_out" => "false"}}
+    filters = [opt_out_filter | filters]
+
+    %{
+      "sort" => "_score",
+      "from" => from,
+      "size" => page_size,
+      # This must be >0, otherwise all documents will be returned
+      "min_score" => 1,
+      "query" => %{
+        "bool" => %{
+          "filter" => filters,
+          "should" => [
+            %{
+              "multi_match" => %{
+                "query" => query,
+                "fields" => [
+                  "description.english",
+                  "domain.english"
+                ]
+              }
+            },
+            %{
+              # If the query exactly matches a domain, that instance should always be the first result.
+              "wildcard" => %{
+                "domain.keyword" => %{
+                  "value" => query,
+                  "boost" => 100
+                }
+              }
+            },
+            %{
+              # Give substring matches in domains a large boost, too.
+              "wildcard" => %{
+                "domain.keyword" => %{
+                  "value" => "*#{query}*",
+                  "boost" => 10
+                }
+              }
+            }
+          ]
+        }
+      }
+    }
+  end
 end
diff --git a/backend/lib/backend_web/controllers/search_controller.ex b/backend/lib/backend_web/controllers/search_controller.ex
index 82a9d3a..89b6fbf 100644
--- a/backend/lib/backend_web/controllers/search_controller.ex
+++ b/backend/lib/backend_web/controllers/search_controller.ex
@@ -7,7 +7,46 @@ defmodule BackendWeb.SearchController do
   def index(conn, params) do
     query = Map.get(params, "query")
     from = Map.get(params, "after", "0") |> String.to_integer()
-    %{hits: hits, next: next} = Api.search_instances(query, from)
+
+    # Filters
+    filter_keys =
+      params
+      |> Map.keys()
+      |> Enum.filter(fn key -> key !== "query" and key !== "after" end)
+
+    filters =
+      params
+      |> Map.take(filter_keys)
+      |> Map.to_list()
+      |> Enum.map(&convert_to_es_filter(&1))
+
+    %{hits: hits, next: next} = Api.search_instances(query, filters, from)
     render(conn, "index.json", hits: hits, next: next)
   end
+
+  defp convert_to_es_filter(url_param) do
+    {key, value} = url_param
+    # Key has the form e.g. "type_eq" or "user_count_gte"
+    key_components = String.split(key, "_")
+    # The field to filter on
+    field = Enum.take(key_components, length(key_components) - 1) |> Enum.join("_")
+    # The filter relation -- one of eq, gt, gte, lt, lte
+    relation = Enum.take(key_components, -1)
+
+    case field do
+      "type" ->
+        %{
+          "term" => %{"type" => value}
+        }
+
+      "user_count" ->
+        %{
+          "range" => %{
+            "user_count" => %{
+              relation => value
+            }
+          }
+        }
+    end
+  end
 end
diff --git a/frontend/src/components/molecules/SearchResult.tsx b/frontend/src/components/molecules/SearchResult.tsx
index 002f308..739e8c8 100644
--- a/frontend/src/components/molecules/SearchResult.tsx
+++ b/frontend/src/components/molecules/SearchResult.tsx
@@ -9,7 +9,7 @@ import { InstanceType } from "../atoms";
 
 const StyledCard = styled(Card)`
   width: 80%;
-  margin: 1em auto;
+  margin: 0.5em auto;
   background-color: #394b59 !important;
   text-align: left;
 `;
diff --git a/frontend/src/components/organisms/SearchFilters.tsx b/frontend/src/components/organisms/SearchFilters.tsx
new file mode 100644
index 0000000..eaf660a
--- /dev/null
+++ b/frontend/src/components/organisms/SearchFilters.tsx
@@ -0,0 +1,68 @@
+import { Button, ITagProps, Menu, MenuItem, Popover, Position, Tag } from "@blueprintjs/core";
+import { IconNames } from "@blueprintjs/icons";
+import React, { MouseEvent } from "react";
+import styled from "styled-components";
+import { INSTANCE_TYPES } from "../../constants";
+import { getSearchFilterDisplayValue, ISearchFilter } from "../../searchFilters";
+import { capitalize } from "../../util";
+
+const SearchFilterContainer = styled.div`
+  margin: 10px 0 0 0;
+`;
+const TagContainer = styled.div`
+  display: flex;
+  flex-direction: row;
+  justify-items: flex-start;
+  margin-bottom: 5px;
+`;
+const StyledTag = styled(Tag)`
+  margin-left: 5px;
+`;
+
+interface ISearchFiltersProps {
+  selectedFilters: ISearchFilter[];
+  selectFilter: (filter: ISearchFilter) => void;
+  deselectFilter: (e: MouseEvent<HTMLButtonElement>, props: ITagProps) => void;
+}
+const SearchFilters: React.FC<ISearchFiltersProps> = ({ selectedFilters, selectFilter, deselectFilter }) => {
+  const hasInstanceTypeFilter = selectedFilters.some(sf => sf.field === "type");
+
+  const handleSelectInstanceType = (e: MouseEvent<HTMLElement>) => {
+    const field = "type";
+    const relation = "eq";
+    const value = e.currentTarget.innerText.toLowerCase();
+    const filter: ISearchFilter = {
+      displayValue: getSearchFilterDisplayValue(field, relation, value),
+      field,
+      relation,
+      value
+    };
+    selectFilter(filter);
+  };
+  const renderMenu = () => (
+    <Menu>
+      <MenuItem icon={IconNames.SYMBOL_CIRCLE} text="Instance type" disabled={hasInstanceTypeFilter}>
+        {INSTANCE_TYPES.map(t => (
+          <MenuItem key={t} text={capitalize(t)} onClick={handleSelectInstanceType} />
+        ))}
+      </MenuItem>
+    </Menu>
+  );
+  return (
+    <SearchFilterContainer>
+      <TagContainer>
+        {selectedFilters.map(filter => (
+          <StyledTag key={filter.displayValue} minimal={true} onRemove={deselectFilter}>
+            {filter.displayValue}
+          </StyledTag>
+        ))}
+      </TagContainer>
+      <Popover autoFocus={false} content={renderMenu()} position={Position.BOTTOM}>
+        <Button minimal={true} icon={IconNames.FILTER}>
+          {"Add filter"}
+        </Button>
+      </Popover>
+    </SearchFilterContainer>
+  );
+};
+export default SearchFilters;
diff --git a/frontend/src/components/organisms/SidebarContainer.tsx b/frontend/src/components/organisms/SidebarContainer.tsx
index 7e390de..6af77a4 100644
--- a/frontend/src/components/organisms/SidebarContainer.tsx
+++ b/frontend/src/components/organisms/SidebarContainer.tsx
@@ -16,8 +16,6 @@ const StyledCard = styled(Card)`
   padding: 20px 0;
   display: flex;
   flex-direction: column;
-  align-items: stretch;
-  justify-content: center;
 `;
 const SidebarContainer: React.FC = ({ children }) => {
   return (
diff --git a/frontend/src/components/organisms/index.ts b/frontend/src/components/organisms/index.ts
index c9013e3..6878bd7 100644
--- a/frontend/src/components/organisms/index.ts
+++ b/frontend/src/components/organisms/index.ts
@@ -1,3 +1,4 @@
 export { default as Graph } from "./Graph";
 export { default as Nav } from "./Nav";
 export { default as SidebarContainer } from "./SidebarContainer";
+export { default as SearchFilters } from "./SearchFilters";
diff --git a/frontend/src/components/screens/SearchScreen.tsx b/frontend/src/components/screens/SearchScreen.tsx
index 6addd17..61ff743 100644
--- a/frontend/src/components/screens/SearchScreen.tsx
+++ b/frontend/src/components/screens/SearchScreen.tsx
@@ -1,27 +1,33 @@
 import { Button, Callout, H2, InputGroup, Intent, NonIdealState, Spinner } from "@blueprintjs/core";
 import { IconNames } from "@blueprintjs/icons";
 import { push } from "connected-react-router";
-import React from "react";
+import { get, isEqual } from "lodash";
+import React, { MouseEvent } from "react";
 import { connect } from "react-redux";
 import { Dispatch } from "redux";
 import styled from "styled-components";
 import { setResultHover, updateSearch } from "../../redux/actions";
 import { IAppState, ISearchResultInstance } from "../../redux/types";
+import { ISearchFilter } from "../../searchFilters";
 import { isSmallScreen } from "../../util";
 import { SearchResult } from "../molecules";
+import { SearchFilters } from "../organisms";
 
-const SearchContainer = styled.div`
-  align-self: center;
-  text-align: center;
-  width: 100%;
-`;
-const SearchBarContainer = styled.div`
+interface ISearchBarContainerProps {
+  hasSearchResults: boolean;
+  hasError: boolean;
+}
+const SearchBarContainer = styled.div<ISearchBarContainerProps>`
   width: 80%;
-  margin: 0 auto;
   text-align: center;
+  margin: ${props => (props.hasSearchResults || props.hasError ? "0 auto" : "auto")};
+  align-self: center;
 `;
 const SearchResults = styled.div`
   width: 100%;
+  display: flex;
+  flex-direction: column;
+  justify-items: center;
 `;
 const StyledSpinner = styled(Spinner)`
   margin-top: 10px;
@@ -38,17 +44,18 @@ interface ISearchScreenProps {
   query: string;
   hasMoreResults: boolean;
   results: ISearchResultInstance[];
-  handleSearch: (query: string) => void;
+  handleSearch: (query: string, filters: ISearchFilter[]) => void;
   navigateToInstance: (domain: string) => void;
   setIsHoveringOver: (domain?: string) => void;
 }
 interface ISearchScreenState {
   currentQuery: string;
+  searchFilters: ISearchFilter[];
 }
 class SearchScreen extends React.PureComponent<ISearchScreenProps, ISearchScreenState> {
   public constructor(props: ISearchScreenProps) {
     super(props);
-    this.state = { currentQuery: "" };
+    this.state = { currentQuery: "", searchFilters: [] };
   }
 
   public componentDidMount() {
@@ -96,19 +103,25 @@ class SearchScreen extends React.PureComponent<ISearchScreenProps, ISearchScreen
     let rightSearchBarElement;
     if (isLoadingResults) {
       rightSearchBarElement = <Spinner size={Spinner.SIZE_SMALL} />;
-    } else if (query) {
+    } else if (query || error) {
       rightSearchBarElement = <Button minimal={true} icon={IconNames.CROSS} onClick={this.clearQuery} />;
     } else {
       rightSearchBarElement = (
-        <Button minimal={true} icon={IconNames.ARROW_RIGHT} intent={Intent.PRIMARY} onClick={this.search} />
+        <Button
+          minimal={true}
+          icon={IconNames.ARROW_RIGHT}
+          intent={Intent.PRIMARY}
+          onClick={this.search}
+          disabled={!this.state.currentQuery}
+        />
       );
     }
 
     return (
-      <SearchContainer>
+      <>
         {isSmallScreen && results.length === 0 && this.renderMobileWarning()}
-        <H2>Find an instance</H2>
-        <SearchBarContainer>
+        <SearchBarContainer hasSearchResults={results.length > 0} hasError={!!error}>
+          <H2>Find an instance</H2>
           <InputGroup
             leftIcon={IconNames.SEARCH}
             rightElement={rightSearchBarElement}
@@ -119,9 +132,14 @@ class SearchScreen extends React.PureComponent<ISearchScreenProps, ISearchScreen
             onChange={this.handleInputChange}
             onKeyPress={this.handleKeyPress}
           />
+          <SearchFilters
+            selectedFilters={this.state.searchFilters}
+            selectFilter={this.selectSearchFilter}
+            deselectFilter={this.deselectSearchFilter}
+          />
         </SearchBarContainer>
         {content}
-      </SearchContainer>
+      </>
     );
   }
 
@@ -136,12 +154,31 @@ class SearchScreen extends React.PureComponent<ISearchScreenProps, ISearchScreen
   };
 
   private search = () => {
-    this.props.handleSearch(this.state.currentQuery);
+    this.props.handleSearch(this.state.currentQuery, this.state.searchFilters);
   };
 
   private clearQuery = () => {
-    this.setState({ currentQuery: "" });
-    this.props.handleSearch("");
+    this.setState({ currentQuery: "" }, () => this.props.handleSearch("", []));
+  };
+
+  private selectSearchFilter = (filter: ISearchFilter) => {
+    const { searchFilters } = this.state;
+    // Don't add the same filters twice
+    if (searchFilters.some(sf => isEqual(sf, filter))) {
+      return;
+    }
+    this.setState({ searchFilters: [...searchFilters, filter] }, this.search);
+  };
+
+  private deselectSearchFilter = (e: MouseEvent<HTMLButtonElement>) => {
+    const { searchFilters } = this.state;
+    const displayValueToRemove = get(e, "currentTarget.parentElement.innerText", "");
+    if (!!displayValueToRemove) {
+      this.setState(
+        { searchFilters: searchFilters.filter(sf => sf.displayValue !== displayValueToRemove) },
+        this.search
+      );
+    }
   };
 
   private selectInstanceFactory = (domain: string) => () => {
@@ -175,7 +212,7 @@ const mapStateToProps = (state: IAppState) => ({
   results: state.search.results
 });
 const mapDispatchToProps = (dispatch: Dispatch) => ({
-  handleSearch: (query: string) => dispatch(updateSearch(query) as any),
+  handleSearch: (query: string, filters: ISearchFilter[]) => dispatch(updateSearch(query, filters) as any),
   navigateToInstance: (domain: string) => dispatch(push(`/instance/${domain}`)),
   setIsHoveringOver: (domain?: string) => dispatch(setResultHover(domain))
 });
diff --git a/frontend/src/constants.tsx b/frontend/src/constants.tsx
index 004ff77..f402c2c 100644
--- a/frontend/src/constants.tsx
+++ b/frontend/src/constants.tsx
@@ -38,3 +38,6 @@ export const INSTANCE_DOMAIN_PATH = "/instance/:domain";
 export interface IInstanceDomainPath {
   domain: string;
 }
+
+// We could also extract the values from the server response, but this would slow things down...
+export const INSTANCE_TYPES = ["mastodon", "gab", "pleroma"];
diff --git a/frontend/src/redux/actions.ts b/frontend/src/redux/actions.ts
index 9178bb1..67a55ba 100644
--- a/frontend/src/redux/actions.ts
+++ b/frontend/src/redux/actions.ts
@@ -1,6 +1,8 @@
+import { isEqual } from "lodash";
 import { Dispatch } from "redux";
 
 import { push } from "connected-react-router";
+import { ISearchFilter } from "../searchFilters";
 import { getFromApi } from "../util";
 import { ActionType, IAppState, IGraph, IInstanceDetails, ISearchResponse } from "./types";
 
@@ -47,9 +49,9 @@ const graphLoadFailed = () => {
 };
 
 // Search
-const requestSearchResult = (query: string) => {
+const requestSearchResult = (query: string, filters: ISearchFilter[]) => {
   return {
-    payload: query,
+    payload: { query, filters },
     type: ActionType.REQUEST_SEARCH_RESULTS
   };
 };
@@ -96,7 +98,7 @@ export const loadInstance = (instanceName: string | null) => {
   };
 };
 
-export const updateSearch = (query: string) => {
+export const updateSearch = (query: string, filters: ISearchFilter[]) => {
   return (dispatch: Dispatch, getState: () => IAppState) => {
     query = query.trim();
 
@@ -105,14 +107,23 @@ export const updateSearch = (query: string) => {
       return;
     }
 
-    const isNewQuery = getState().search.query !== query;
+    const prevQuery = getState().search.query;
+    const prevFilters = getState().search.filters;
+    const isNewQuery = prevQuery !== query || !isEqual(prevFilters, filters);
 
     const next = getState().search.next;
     let url = `search/?query=${query}`;
     if (!isNewQuery && next) {
       url += `&after=${next}`;
     }
-    dispatch(requestSearchResult(query));
+
+    // Add filters
+    // The format is e.g. type_eq=mastodon or user_count_gt=1000
+    filters.forEach(filter => {
+      url += `&${filter.field}_${filter.relation}=${filter.value}`;
+    });
+
+    dispatch(requestSearchResult(query, filters));
     return getFromApi(url)
       .then(result => dispatch(receiveSearchResults(result)))
       .catch(() => dispatch(searchFailed()));
diff --git a/frontend/src/redux/reducers.ts b/frontend/src/redux/reducers.ts
index 6803bdb..47293ee 100644
--- a/frontend/src/redux/reducers.ts
+++ b/frontend/src/redux/reducers.ts
@@ -1,4 +1,5 @@
 import { connectRouter } from "connected-react-router";
+import { isEqual } from "lodash";
 import { combineReducers } from "redux";
 
 import { History } from "history";
@@ -72,6 +73,7 @@ const currentInstance = (state = initialCurrentInstanceState, action: IAction):
 
 const initialSearchState: ISearchState = {
   error: false,
+  filters: [],
   isLoadingResults: false,
   next: "",
   query: "",
@@ -80,11 +82,12 @@ const initialSearchState: ISearchState = {
 const search = (state = initialSearchState, action: IAction): ISearchState => {
   switch (action.type) {
     case ActionType.REQUEST_SEARCH_RESULTS:
-      const query = action.payload;
-      const isNewQuery = state.query !== query;
+      const { query, filters } = action.payload;
+      const isNewQuery = state.query !== query || !isEqual(state.filters, filters);
       return {
         ...state,
         error: false,
+        filters,
         isLoadingResults: true,
         next: isNewQuery ? "" : state.next,
         query,
@@ -99,14 +102,7 @@ const search = (state = initialSearchState, action: IAction): ISearchState => {
         results: state.results.concat(action.payload.results)
       };
     case ActionType.SEARCH_RESULTS_ERROR:
-      return {
-        ...state,
-        error: true,
-        isLoadingResults: false,
-        next: "",
-        query: "",
-        results: []
-      };
+      return { ...initialSearchState, error: true };
     case ActionType.RESET_SEARCH:
       return initialSearchState;
     case ActionType.SET_SEARCH_RESULT_HOVER:
diff --git a/frontend/src/redux/types.ts b/frontend/src/redux/types.ts
index 5c21dac..a516330 100644
--- a/frontend/src/redux/types.ts
+++ b/frontend/src/redux/types.ts
@@ -1,4 +1,5 @@
 import { RouterState } from "connected-react-router";
+import { ISearchFilter } from "../searchFilters";
 
 export enum ActionType {
   // Instance details
@@ -113,6 +114,7 @@ export interface ISearchState {
   next: string;
   query: string;
   results: ISearchResultInstance[];
+  filters: ISearchFilter[];
   hoveringOverResult?: string;
 }
 
diff --git a/frontend/src/searchFilters.ts b/frontend/src/searchFilters.ts
new file mode 100644
index 0000000..e6d9a88
--- /dev/null
+++ b/frontend/src/searchFilters.ts
@@ -0,0 +1,26 @@
+type ISearchFilterRelation = "eq" | "gt" | "gte" | "lt" | "lte";
+export interface ISearchFilter {
+  // The ES field to filter on
+  field: string;
+  relation: ISearchFilterRelation;
+  // The value we want to filter to
+  value: string;
+  // Human-meaningful text that we're showing in the UI
+  displayValue: string;
+}
+
+// Maps to translate this to user-friendly text
+const searchFilterFieldTranslations = {
+  type: "Instance type",
+  user_count: "User count"
+};
+const searchFilterRelationTranslations = {
+  eq: "=",
+  gt: ">",
+  gte: ">=",
+  lt: "<",
+  lte: "<="
+};
+
+export const getSearchFilterDisplayValue = (field: string, relation: ISearchFilterRelation, value: string) =>
+  `${searchFilterFieldTranslations[field]} ${searchFilterRelationTranslations[relation]} ${value}`;
diff --git a/frontend/src/types.ts b/frontend/src/types.ts
index 610a0a9..a9fe532 100644
--- a/frontend/src/types.ts
+++ b/frontend/src/types.ts
@@ -1,3 +1,5 @@
+import { INSTANCE_TYPES } from "./constants";
+
 interface IColorSchemeBase {
   // The name of the coloring, e.g. "Instance type"
   name: string;
@@ -23,8 +25,7 @@ export const typeColorScheme: IQualitativeColorScheme = {
   cytoscapeDataKey: "type",
   name: "Instance type",
   type: "qualitative",
-  // We could also extract the values from the server response, but this would slow things down...
-  values: ["mastodon", "gab", "pleroma"]
+  values: INSTANCE_TYPES
 };
 export const activityColorScheme: IQuantitativeColorScheme = {
   cytoscapeDataKey: "statusesPerDay",