diff --git a/backend/config/config.exs b/backend/config/config.exs
index 22d1bc9..0e20258 100644
--- a/backend/config/config.exs
+++ b/backend/config/config.exs
@@ -16,10 +16,12 @@ config :backend, BackendWeb.Endpoint,
   secret_key_base: System.get_env("SECRET_KEY_BASE"),
   render_errors: [view: BackendWeb.ErrorView, accepts: ~w(json)]
 
+config :backend, :http, Backend.Http
+
 config :backend, Backend.Repo, queue_target: 5000
 
 config :backend, Backend.Elasticsearch.Cluster,
-  url: "http://elastic:9200",
+  url: "http://localhost:9200",
   api: Elasticsearch.API.HTTP,
   json_library: Jason
 
diff --git a/backend/lib/backend/application.ex b/backend/lib/backend/application.ex
index 2d8ec13..86c08bf 100644
--- a/backend/lib/backend/application.ex
+++ b/backend/lib/backend/application.ex
@@ -31,9 +31,10 @@ defmodule Backend.Application do
     ]
 
     children =
-      case Enum.member?(["true", 1, "1"], System.get_env("SKIP_CRAWL")) do
-        true -> children
-        false -> children ++ [Backend.Crawler.StaleInstanceManager]
+      if Enum.member?(["true", 1, "1"], System.get_env("SKIP_CRAWL")) or Mix.env() == :test do
+        children
+      else
+        children ++ [Backend.Crawler.StaleInstanceManager]
       end
 
     add_appsignal_probes()
diff --git a/backend/lib/backend/crawler/crawler.ex b/backend/lib/backend/crawler/crawler.ex
index 9f69866..62526d0 100644
--- a/backend/lib/backend/crawler/crawler.ex
+++ b/backend/lib/backend/crawler/crawler.ex
@@ -117,8 +117,8 @@ defmodule Backend.Crawler do
         try do
           %Crawler{state | result: curr.crawl(domain, result), found_api?: true}
         rescue
-          e in HTTPoison.Error ->
-            Map.put(state, :error, "HTTPoison error: " <> HTTPoison.Error.message(e))
+          e in Backend.HttpBehaviour.Error ->
+            Map.put(state, :error, "HTTP error: " <> e.message)
 
           e in Jason.DecodeError ->
             Map.put(state, :error, "Jason DecodeError: " <> Jason.DecodeError.message(e))
diff --git a/backend/lib/backend/crawler/crawlers/friendica.ex b/backend/lib/backend/crawler/crawlers/friendica.ex
index 27c748d..7ec90e3 100644
--- a/backend/lib/backend/crawler/crawlers/friendica.ex
+++ b/backend/lib/backend/crawler/crawlers/friendica.ex
@@ -51,7 +51,7 @@ defmodule Backend.Crawler.Crawlers.Friendica do
       |> Map.merge(nodeinfo_result)
 
     peers =
-      case get_and_decode("https://#{domain}/poco/@server") do
+      case http_client().get_and_decode("https://#{domain}/poco/@server") do
         {:ok, p} -> p
         {:error, _err} -> []
       end
@@ -71,7 +71,7 @@ defmodule Backend.Crawler.Crawlers.Friendica do
   end
 
   defp get_statistics(domain) do
-    get_and_decode("https://#{domain}/statistics.json")
+    http_client().get_and_decode("https://#{domain}/statistics.json")
   end
 
   defp to_domain(url) do
diff --git a/backend/lib/backend/crawler/crawlers/gnu_social.ex b/backend/lib/backend/crawler/crawlers/gnu_social.ex
index 67f55ea..c7e2307 100644
--- a/backend/lib/backend/crawler/crawlers/gnu_social.ex
+++ b/backend/lib/backend/crawler/crawlers/gnu_social.ex
@@ -14,7 +14,7 @@ defmodule Backend.Crawler.Crawlers.GnuSocial do
     if nodeinfo_result != nil do
       Map.get(nodeinfo_result, :instance_type) == :gnusocial
     else
-      case get_and_decode("https://#{domain}/api/statuses/public_timeline.json") do
+      case http_client().get_and_decode("https://#{domain}/api/statuses/public_timeline.json") do
         {:ok, statuses} -> is_list(statuses)
         {:error, _other} -> false
       end
@@ -86,7 +86,7 @@ defmodule Backend.Crawler.Crawlers.GnuSocial do
 
     Logger.debug("Crawling #{endpoint}")
 
-    statuses = get_and_decode!(endpoint)
+    statuses = http_client().get_and_decode!(endpoint)
 
     # Filter to statuses that are in the correct timeframe
     filtered_statuses =
diff --git a/backend/lib/backend/crawler/crawlers/mastodon.ex b/backend/lib/backend/crawler/crawlers/mastodon.ex
index dc9d2a6..2109339 100644
--- a/backend/lib/backend/crawler/crawlers/mastodon.ex
+++ b/backend/lib/backend/crawler/crawlers/mastodon.ex
@@ -21,7 +21,7 @@ defmodule Backend.Crawler.Crawlers.Mastodon do
         true -> false
       end
     else
-      case get_and_decode("https://#{domain}/api/v1/instance") do
+      case http_client().get_and_decode("https://#{domain}/api/v1/instance") do
         {:ok, %{"title" => _title}} -> true
         _other -> false
       end
@@ -41,7 +41,7 @@ defmodule Backend.Crawler.Crawlers.Mastodon do
 
   @impl ApiCrawler
   def crawl(domain, nodeinfo) do
-    instance = get_and_decode!("https://#{domain}/api/v1/instance")
+    instance = http_client().get_and_decode!("https://#{domain}/api/v1/instance")
     user_count = get_in(instance, ["stats", "user_count"])
 
     if is_above_user_threshold?(user_count) or has_opted_in?(domain) do
@@ -117,7 +117,7 @@ defmodule Backend.Crawler.Crawlers.Mastodon do
 
     Logger.debug("Crawling #{endpoint}")
 
-    statuses = get_and_decode!(endpoint)
+    statuses = http_client().get_and_decode!(endpoint)
 
     filtered_statuses =
       statuses
@@ -161,7 +161,7 @@ defmodule Backend.Crawler.Crawlers.Mastodon do
 
   defp get_peers(domain) do
     # servers may not publish peers
-    case get_and_decode("https://#{domain}/api/v1/instance/peers") do
+    case http_client().get_and_decode("https://#{domain}/api/v1/instance/peers") do
       {:ok, peers} -> peers
       {:error, _err} -> []
     end
diff --git a/backend/lib/backend/crawler/crawlers/misskey.ex b/backend/lib/backend/crawler/crawlers/misskey.ex
index fe8f116..9ee734b 100644
--- a/backend/lib/backend/crawler/crawlers/misskey.ex
+++ b/backend/lib/backend/crawler/crawlers/misskey.ex
@@ -3,6 +3,7 @@ defmodule Backend.Crawler.Crawlers.Misskey do
   Crawler for Misskey servers.
   """
   alias Backend.Crawler.ApiCrawler
+  alias Backend.Http
 
   @behaviour ApiCrawler
   import Backend.Crawler.Util
@@ -37,7 +38,7 @@ defmodule Backend.Crawler.Crawlers.Misskey do
   @impl ApiCrawler
   def crawl(domain, nodeinfo) do
     with {:ok, %{"originalUsersCount" => user_count, "originalNotesCount" => status_count}} <-
-           post_and_decode("https://#{domain}/api/stats") do
+           http_client().post_and_decode("https://#{domain}/api/stats") do
       if is_above_user_threshold?(user_count) or has_opted_in?(domain) do
         Map.merge(nodeinfo, crawl_large_instance(domain, user_count, status_count))
       else
@@ -109,7 +110,7 @@ defmodule Backend.Crawler.Crawlers.Misskey do
 
     Logger.debug("Crawling #{endpoint} with untilId=#{until_id}")
 
-    statuses = post_and_decode!(endpoint, Jason.encode!(params))
+    statuses = http_client().post_and_decode!(endpoint, Jason.encode!(params))
 
     filtered_statuses =
       statuses
@@ -153,9 +154,9 @@ defmodule Backend.Crawler.Crawlers.Misskey do
   end
 
   @spec get_version_and_description(String.t()) ::
-          {:ok, {String.t(), String.t()}} | {:error, Jason.DecodeError.t() | HTTPoison.Error.t()}
+          {:ok, {String.t(), String.t()}} | {:error, Jason.DecodeError.t() | Http.Error.t()}
   defp get_version_and_description(domain) do
-    case post_and_decode("https://#{domain}/api/meta") do
+    case http_client().post_and_decode("https://#{domain}/api/meta") do
       {:ok, %{"version" => version, "description" => description}} ->
         {:ok, {version, description}}
 
@@ -166,7 +167,7 @@ defmodule Backend.Crawler.Crawlers.Misskey do
 
   @spec get_peers(String.t()) :: {:ok, [String.t()]} | {:error, Jason.DecodeError.t()}
   defp get_peers(domain) do
-    case get_and_decode("https://#{domain}/api/v1/instance/peers") do
+    case http_client().get_and_decode("https://#{domain}/api/v1/instance/peers") do
       {:ok, peers} -> {:ok, peers}
       {:error, _} -> {:ok, []}
     end
diff --git a/backend/lib/backend/crawler/crawlers/nodeinfo.ex b/backend/lib/backend/crawler/crawlers/nodeinfo.ex
index c3c002d..d26cdec 100644
--- a/backend/lib/backend/crawler/crawlers/nodeinfo.ex
+++ b/backend/lib/backend/crawler/crawlers/nodeinfo.ex
@@ -5,6 +5,7 @@ defmodule Backend.Crawler.Crawlers.Nodeinfo do
   """
 
   alias Backend.Crawler.ApiCrawler
+  alias Backend.Http
   require Logger
   import Backend.Util
   import Backend.Crawler.Util
@@ -13,7 +14,7 @@ defmodule Backend.Crawler.Crawlers.Nodeinfo do
   @impl ApiCrawler
   def allows_crawling?(domain) do
     [
-      ".well-known/nodeinfo"
+      "/.well-known/nodeinfo"
     ]
     |> Enum.map(fn endpoint -> "https://#{domain}#{endpoint}" end)
     |> urls_are_crawlable?()
@@ -36,26 +37,40 @@ defmodule Backend.Crawler.Crawlers.Nodeinfo do
   end
 
   @spec get_nodeinfo_url(String.t()) ::
-          {:ok, String.t()} | {:error, Jason.DecodeError.t() | HTTPoison.Error.t()}
+          {:ok, String.t()} | {:error, Jason.DecodeError.t() | Http.Error.t() | :invalid_body}
   defp get_nodeinfo_url(domain) do
-    case get_and_decode("https://#{domain}/.well-known/nodeinfo") do
-      {:ok, response} -> {:ok, process_nodeinfo_url(response)}
-      {:error, err} -> {:error, err}
+    with {:ok, response} <-
+           http_client().get_and_decode("https://#{domain}/.well-known/nodeinfo"),
+         {:ok, nodeinfo_url} <- process_nodeinfo_url(response) do
+      {:ok, nodeinfo_url}
+    else
+      {:error, error} -> {:error, error}
+      :error -> {:error, :invalid_body}
     end
   end
 
-  @spec process_nodeinfo_url(any()) :: String.t()
+  @spec process_nodeinfo_url(any()) :: {:ok, String.t()} | :error
   defp process_nodeinfo_url(response) do
-    response
-    |> Map.get("links")
-    |> Enum.filter(fn %{"rel" => rel} -> is_compatible_nodeinfo_version?(rel) end)
-    |> Kernel.hd()
-    |> Map.get("href")
+    links =
+      response
+      |> Map.get("links", [])
+      |> Enum.filter(fn %{"rel" => rel} -> is_compatible_nodeinfo_version?(rel) end)
+
+    if Enum.empty?(links) do
+      :error
+    else
+      href =
+        links
+        |> Kernel.hd()
+        |> Map.get("href")
+
+      {:ok, href}
+    end
   end
 
   @spec get_nodeinfo(String.t()) :: ApiCrawler.t()
   defp get_nodeinfo(nodeinfo_url) do
-    case get_and_decode(nodeinfo_url) do
+    case http_client().get_and_decode(nodeinfo_url) do
       {:ok, nodeinfo} -> {:ok, process_nodeinfo(nodeinfo)}
       {:error, err} -> {:error, err}
     end
diff --git a/backend/lib/backend/http.ex b/backend/lib/backend/http.ex
new file mode 100644
index 0000000..876de0f
--- /dev/null
+++ b/backend/lib/backend/http.ex
@@ -0,0 +1,71 @@
+defmodule Backend.Http do
+  @moduledoc """
+  A wrapper around HTTPoison. Using this wrapper makes it easy for us
+  to mock web responses in tests, and we can easily switch out HTTPoison for
+  another library if we want to.
+  """
+  @behaviour Backend.HttpBehaviour
+  alias Backend.HttpBehaviour.Error
+
+  import Backend.Util
+
+  @doc """
+  GETs from the given URL and returns the JSON-decoded response.
+  If the response is unsuccessful and a default value is given, this returns the default value.
+  Otherwise, unsuccessful responses return an error.
+  """
+  @impl true
+  def get_and_decode(url, pool \\ :default, timeout \\ 15_000, default \\ nil) do
+    case HTTPoison.get(url, [{"User-Agent", get_config(:user_agent)}],
+           hackney: [pool: pool],
+           recv_timeout: timeout,
+           timeout: timeout
+         ) do
+      {:ok, %HTTPoison.Response{body: body, status_code: status_code}}
+      when status_code >= 200 and status_code <= 299 ->
+        Jason.decode(body)
+
+      {:ok, %HTTPoison.Response{body: body, status_code: status_code}} ->
+        if not is_nil(default) do
+          {:ok, default}
+        else
+          {:error,
+           %Error{
+             message: "HTTP request failed with status code #{status_code}",
+             status_code: status_code,
+             body: body
+           }}
+        end
+
+      {:error, %HTTPoison.Error{} = error} ->
+        {:error, %Error{message: HTTPoison.Error.message(error)}}
+    end
+  end
+
+  @impl true
+  def get_and_decode!(url, pool \\ :default, timeout \\ 15_000, default \\ nil) do
+    case get_and_decode(url, pool, timeout, default) do
+      {:ok, decoded} -> decoded
+      {:error, error} -> raise error
+    end
+  end
+
+  @impl true
+  def post_and_decode(url, body \\ nil) do
+    case HTTPoison.post(url, body, [{"User-Agent", get_config(:user_agent)}]) do
+      {:ok, %HTTPoison.Response{body: body}} ->
+        Jason.decode(body)
+
+      {:error, %HTTPoison.Error{} = error} ->
+        {:error, %Error{message: HTTPoison.Error.message(error)}}
+    end
+  end
+
+  @impl true
+  def post_and_decode!(url, body \\ nil) do
+    case post_and_decode(url, body) do
+      {:ok, decoded} -> decoded
+      {:error, error} -> raise error
+    end
+  end
+end
diff --git a/backend/lib/backend/http_behaviour.ex b/backend/lib/backend/http_behaviour.ex
new file mode 100644
index 0000000..6dd0df4
--- /dev/null
+++ b/backend/lib/backend/http_behaviour.ex
@@ -0,0 +1,23 @@
+defmodule Backend.HttpBehaviour do
+  @moduledoc """
+  This module defines the behavior for HTTP requests.
+  """
+
+  defmodule Error do
+    defstruct message: nil, status_code: nil, body: nil
+    @type t :: %__MODULE__{message: String.t(), status_code: integer | nil, body: term | nil}
+  end
+
+  @type response :: {:ok, Response.t()} | {:error, __MODULE__.Error.t() | Jason.DecodeError.t()}
+
+  @callback get_and_decode(String.t()) :: response
+  @callback get_and_decode(String.t(), Atom.t(), Integer.t(), any()) :: response
+
+  @callback get_and_decode!(String.t()) :: Response.t()
+  @callback get_and_decode!(String.t(), Atom.t(), Integer.t(), any()) :: Response.t()
+
+  @callback post_and_decode(String.t()) :: response()
+  @callback post_and_decode(String.t(), String.t()) :: response()
+  @callback post_and_decode!(String.t()) :: Response.t()
+  @callback post_and_decode!(String.t(), String.t()) :: Response.t()
+end
diff --git a/backend/lib/backend/util.ex b/backend/lib/backend/util.ex
index ccbf0ed..3ed35bc 100644
--- a/backend/lib/backend/util.ex
+++ b/backend/lib/backend/util.ex
@@ -143,69 +143,12 @@ defmodule Backend.Util do
     map |> Map.new(fn {k, v} -> {String.to_atom(k), v} end)
   end
 
-  @doc """
-  Gets and decodes a HTTP response.
-  """
-  @spec get_and_decode(String.t(), Atom.t(), Integer.t()) ::
-          {:ok, any()} | {:error, Jason.DecodeError.t() | HTTPoison.Error.t()}
-  def get_and_decode(url, pool \\ :crawler, timeout \\ 15_000) do
-    case HTTPoison.get(url, [{"User-Agent", get_config(:user_agent)}],
-           hackney: [pool: pool],
-           recv_timeout: timeout,
-           timeout: timeout
-         ) do
-      {:ok, %{status_code: 200, body: body}} ->
-        Jason.decode(body)
-
-      {:ok, %{status_code: 401}} ->
-        Jason.decode("[]")
-
-      {:ok, %{status_code: 404}} ->
-        Jason.decode("[]")
-
-      {:ok, %{body: body}} ->
-        {:error, %HTTPoison.Error{reason: "Non-200 response. Body: #{body}"}}
-
-      {:error, err} ->
-        {:error, err}
-    end
-  end
-
-  @spec get_and_decode!(String.t()) :: any()
-  def get_and_decode!(url) do
-    case get_and_decode(url) do
-      {:ok, decoded} -> decoded
-      {:error, error} -> raise error
-    end
-  end
-
-  @doc """
-  POSTS to a HTTP endpoint and decodes the JSON response.
-  """
-  @spec post_and_decode(String.t(), String.t()) ::
-          {:ok, any()} | {:error, Jason.DecodeError.t() | HTTPoison.Error.t()}
-  def post_and_decode(url, body \\ "") do
-    case HTTPoison.post(url, body, [{"User-Agent", get_config(:user_agent)}],
-           hackney: [pool: :crawler],
-           recv_timeout: 15_000,
-           timeout: 15_000
-         ) do
-      {:ok, %{status_code: 200, body: response_body}} -> Jason.decode(response_body)
-      {:ok, _} -> {:error, %HTTPoison.Error{reason: "Non-200 response"}}
-      {:error, err} -> {:error, err}
-    end
-  end
-
-  @spec post_and_decode!(String.t(), String.t()) :: any()
-  def post_and_decode!(url, body \\ "") do
-    case post_and_decode(url, body) do
-      {:ok, decoded} -> decoded
-      {:error, error} -> raise error
-    end
-  end
-
   @spec is_valid_domain?(String.t()) :: boolean
   def is_valid_domain?(domain) do
     Regex.match?(~r/^[\pL\d\.\-_]+\.[a-zA-Z]+$/, domain)
   end
+
+  def http_client() do
+    Application.get_env(:backend, :http, Backend.Http)
+  end
 end
diff --git a/backend/lib/backend_web/controllers/admin_login_controller.ex b/backend/lib/backend_web/controllers/admin_login_controller.ex
index 3b781f8..974a300 100644
--- a/backend/lib/backend_web/controllers/admin_login_controller.ex
+++ b/backend/lib/backend_web/controllers/admin_login_controller.ex
@@ -5,7 +5,7 @@ defmodule BackendWeb.AdminLoginController do
   alias Backend.Mailer.UserEmail
   alias Mastodon.Messenger
 
-  action_fallback BackendWeb.FallbackController
+  action_fallback(BackendWeb.FallbackController)
 
   @doc """
   Given an instance, looks up the login types (email or admin account) and returns them. The user can then
@@ -24,7 +24,7 @@ defmodule BackendWeb.AdminLoginController do
           [error: "It is only possible to administer Mastodon and Pleroma instances."]
 
         true ->
-          case get_and_decode("https://#{cleaned_domain}/api/v1/instance") do
+          case http_client().get_and_decode("https://#{cleaned_domain}/api/v1/instance") do
             {:ok, instance_data} ->
               [instance_data: instance_data, cleaned_domain: cleaned_domain]
 
@@ -40,7 +40,7 @@ defmodule BackendWeb.AdminLoginController do
     cleaned_domain = clean_domain(domain)
 
     {data_state, instance_data} =
-      get_and_decode("https://#{cleaned_domain}/api/v1/instance",
+      http_client().get_and_decode("https://#{cleaned_domain}/api/v1/instance",
         pool: :admin_login,
         timeout: 20_000
       )
diff --git a/backend/mix.exs b/backend/mix.exs
index cc02d54..036aa42 100644
--- a/backend/mix.exs
+++ b/backend/mix.exs
@@ -72,7 +72,8 @@ defmodule Backend.MixProject do
       {:scrivener_ecto, "~> 2.2"},
       {:recase, "~> 0.7"},
       {:ex_rated, "~> 2.1"},
-      {:html_sanitize_ex, "~> 1.4"}
+      {:html_sanitize_ex, "~> 1.4"},
+      {:mox, "~> 1.0", only: [:test]}
     ]
   end
 
diff --git a/backend/mix.lock b/backend/mix.lock
index 02b8ea6..bbf6e1b 100644
--- a/backend/mix.lock
+++ b/backend/mix.lock
@@ -42,6 +42,7 @@
   "mime": {:hex, :mime, "2.0.5", "dc34c8efd439abe6ae0343edbb8556f4d63f178594894720607772a041b04b02", [:mix], [], "hexpm", "da0d64a365c45bc9935cc5c8a7fc5e49a0e0f9932a761c55d6c52b142780a05c"},
   "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"},
   "mochiweb": {:hex, :mochiweb, "2.22.0", "f104d6747c01a330c38613561977e565b788b9170055c5241ac9dd6e4617cba5", [:rebar3], [], "hexpm", "cbbd1fd315d283c576d1c8a13e0738f6dafb63dc840611249608697502a07655"},
+  "mox": {:hex, :mox, "1.0.2", "dc2057289ac478b35760ba74165b4b3f402f68803dd5aecd3bfd19c183815d64", [:mix], [], "hexpm", "f9864921b3aaf763c8741b5b8e6f908f44566f1e427b2630e89e9a73b981fef2"},
   "nebulex": {:hex, :nebulex, "2.4.2", "b3d2d86d57b15896fb8e6d6dd49b4a9dee2eedd6eddfb3b69bfdb616a09c2817", [:mix], [{:decorator, "~> 1.4", [hex: :decorator, repo: "hexpm", optional: true]}, {:shards, "~> 1.0", [hex: :shards, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: true]}], "hexpm", "c9f888e5770fd47614c95990d0a02c3515216d51dc72e3c830eaf28f5649ba52"},
   "parse_trans": {:hex, :parse_trans, "3.3.1", "16328ab840cc09919bd10dab29e431da3af9e9e7e7e6f0089dd5a2d2820011d8", [:rebar3], [], "hexpm", "07cd9577885f56362d414e8c4c4e6bdf10d43a8767abb92d24cbe8b24c54888b"},
   "phoenix": {:hex, :phoenix, "1.7.3", "4d8eca2c020c9ed81a28e7a8c60e0a4f6f9f7f6e12eb91dfd01301eac07424c1", [:mix], [{:castore, ">= 0.0.0", [hex: :castore, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.1", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:websock_adapter, "~> 0.4", [hex: :websock_adapter, repo: "hexpm", optional: false]}], "hexpm", "6b1bc308758f95ecf3e0d795389440a2ca88a903e0fda1f921c780918c16d640"},
diff --git a/backend/test/backend/crawler/crawlers/nodeinfo_test.exs b/backend/test/backend/crawler/crawlers/nodeinfo_test.exs
new file mode 100644
index 0000000..92fe547
--- /dev/null
+++ b/backend/test/backend/crawler/crawlers/nodeinfo_test.exs
@@ -0,0 +1,138 @@
+defmodule Backend.Crawler.Crawlers.NodeinfoTest do
+  use Backend.DataCase
+
+  alias Backend.Crawler.Crawlers.Nodeinfo
+  import Mox
+
+  setup :verify_on_exit!
+
+  describe "crawl/2" do
+    test "handles valid nodeinfo" do
+      expect(HttpMock, :get_and_decode, fn "https://mastodon.social/.well-known/nodeinfo" ->
+        {:ok,
+         %{
+           "links" => [
+             %{
+               "rel" => "http://nodeinfo.diaspora.software/ns/schema/2.0",
+               "href" => "https://mastodon.social/nodeinfo/2.0"
+             }
+           ]
+         }}
+      end)
+
+      expect(HttpMock, :get_and_decode, fn "https://mastodon.social/nodeinfo/2.0" ->
+        {:ok,
+         %{
+           "version" => "2.0",
+           "software" => %{
+             "name" => "Mastodon",
+             "version" => "1.2.3"
+           },
+           "protocols" => ["activitypub"],
+           "services" => %{
+             "inbound" => [],
+             "outbound" => []
+           },
+           "usage" => %{
+             "users" => %{
+               "total" => 100,
+               "activeMonth" => 1,
+               "activeHalfYear" => 2
+             },
+             "localPosts" => 3
+           },
+           "openRegistrations" => true,
+           "metadata" => %{}
+         }}
+      end)
+
+      result = Nodeinfo.crawl("mastodon.social", %{})
+
+      assert result == %{
+               description: nil,
+               user_count: 100,
+               status_count: 3,
+               statuses_seen: 0,
+               instance_type: :mastodon,
+               version: "1.2.3",
+               federation_restrictions: [],
+               interactions: %{},
+               peers: []
+             }
+    end
+
+    test "handles small instances" do
+      expect(HttpMock, :get_and_decode, fn "https://mastodon.social/.well-known/nodeinfo" ->
+        {:ok,
+         %{
+           "links" => [
+             %{
+               "rel" => "http://nodeinfo.diaspora.software/ns/schema/2.0",
+               "href" => "https://mastodon.social/nodeinfo/2.0"
+             }
+           ]
+         }}
+      end)
+
+      expect(HttpMock, :get_and_decode, fn "https://mastodon.social/nodeinfo/2.0" ->
+        {:ok,
+         %{
+           "version" => "2.0",
+           "software" => %{
+             "name" => "Mastodon",
+             "version" => "1.2.3"
+           },
+           "protocols" => ["activitypub"],
+           "services" => %{
+             "inbound" => [],
+             "outbound" => []
+           },
+           "usage" => %{
+             "users" => %{
+               "total" => 1,
+               "activeMonth" => 1,
+               "activeHalfYear" => 1
+             },
+             "localPosts" => 3
+           },
+           "openRegistrations" => true,
+           "metadata" => %{}
+         }}
+      end)
+
+      result = Nodeinfo.crawl("mastodon.social", %{})
+
+      assert result == %{
+               description: nil,
+               user_count: 1,
+               status_count: nil,
+               statuses_seen: 0,
+               instance_type: nil,
+               version: nil,
+               federation_restrictions: [],
+               interactions: %{},
+               peers: []
+             }
+    end
+
+    test "handles missing nodeinfo" do
+      expect(HttpMock, :get_and_decode, fn "https://mastodon.social/.well-known/nodeinfo" ->
+        {:ok, %{}}
+      end)
+
+      result = Nodeinfo.crawl("mastodon.social", %{})
+
+      assert result == %{
+               description: nil,
+               user_count: nil,
+               status_count: nil,
+               statuses_seen: 0,
+               instance_type: nil,
+               version: nil,
+               federation_restrictions: [],
+               interactions: %{},
+               peers: []
+             }
+    end
+  end
+end
diff --git a/backend/test/test_helper.exs b/backend/test/test_helper.exs
index a7d0703..292fc2d 100644
--- a/backend/test/test_helper.exs
+++ b/backend/test/test_helper.exs
@@ -1,2 +1,5 @@
+Mox.defmock(HttpMock, for: Backend.HttpBehaviour)
+Application.put_env(:backend, :http, HttpMock)
+
 ExUnit.start()
 Ecto.Adapters.SQL.Sandbox.mode(Backend.Repo, :manual)