diff --git a/lib/federation/node_info.ex b/lib/federation/node_info.ex
index b37bd3e96..bf17b788c 100644
--- a/lib/federation/node_info.ex
+++ b/lib/federation/node_info.ex
@@ -5,6 +5,7 @@ defmodule Mobilizon.Federation.NodeInfo do
 
   alias Mobilizon.Service.HTTP.WebfingerClient
   require Logger
+  import Mobilizon.Service.HTTP.Utils, only: [is_content_type?: 2]
 
   @application_uri "https://www.w3.org/ns/activitystreams#Application"
   @nodeinfo_rel_2_0 "http://nodeinfo.diaspora.software/ns/schema/2.0"
@@ -31,7 +32,9 @@ defmodule Mobilizon.Federation.NodeInfo do
 
     with {:ok, endpoint} when is_binary(endpoint) <- fetch_nodeinfo_details(host),
          :ok <- Logger.debug("Going to get NodeInfo information from URL #{endpoint}"),
-         {:ok, %{body: body, status: code}} when code in 200..299 <- WebfingerClient.get(endpoint) do
+         {:ok, %{body: body, status: code, headers: headers}} when code in 200..299 <-
+           WebfingerClient.get(endpoint),
+         {:ok, body} <- validate_json_response(body, headers) do
       Logger.debug("Found nodeinfo information for domain #{host}")
       {:ok, body}
     else
@@ -58,8 +61,8 @@ defmodule Mobilizon.Federation.NodeInfo do
     prefix = if @env !== :dev, do: "https", else: "http"
 
     case WebfingerClient.get("#{prefix}://#{host}/.well-known/nodeinfo") do
-      {:ok, %{body: body, status: code}} when code in 200..299 ->
-        {:ok, body}
+      {:ok, %{body: body, status: code, headers: headers}} when code in 200..299 ->
+        validate_json_response(body, headers)
 
       err ->
         Logger.debug("Failed to fetch NodeInfo data #{inspect(err)}")
@@ -102,4 +105,19 @@ defmodule Mobilizon.Federation.NodeInfo do
       rel == relation and is_binary(href)
     end)
   end
+
+  @spec validate_json_response(map() | String.t(), list()) ::
+          {:ok, String.t()} | {:error, :bad_content_type | :body_not_json}
+  defp validate_json_response(body, headers) do
+    cond do
+      !is_content_type?(headers, "application/json") ->
+        {:error, :bad_content_type}
+
+      !is_map(body) ->
+        {:error, :body_not_json}
+
+      true ->
+        {:ok, body}
+    end
+  end
 end
diff --git a/test/federation/node_info_test.exs b/test/federation/node_info_test.exs
index d4f34d6c7..203040bc9 100644
--- a/test/federation/node_info_test.exs
+++ b/test/federation/node_info_test.exs
@@ -24,7 +24,12 @@ defmodule Mobilizon.Federation.NodeInfoTest do
           url: "https://event-federation.eu/.well-known/nodeinfo"
         },
         _opts ->
-          {:ok, %Tesla.Env{status: 200, body: nodeinfo_data}}
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: nodeinfo_data,
+             headers: [{"content-type", "application/json"}]
+           }}
       end)
 
       assert "https://event-federation.eu/actor-relay" ==
@@ -76,7 +81,12 @@ defmodule Mobilizon.Federation.NodeInfoTest do
           url: "https://mobilizon.fr/.well-known/nodeinfo"
         },
         _opts ->
-          {:ok, %Tesla.Env{status: 200, body: nodeinfo_end_point_data}}
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: nodeinfo_end_point_data,
+             headers: [{"content-type", "application/json"}]
+           }}
       end)
 
       WebfingerClientMock
@@ -86,7 +96,12 @@ defmodule Mobilizon.Federation.NodeInfoTest do
           url: "https://mobilizon.fr/.well-known/nodeinfo/2.1"
         },
         _opts ->
-          {:ok, %Tesla.Env{status: 200, body: nodeinfo_data}}
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: nodeinfo_data,
+             headers: [{"content-type", "application/json"}]
+           }}
       end)
 
       assert {:ok, data} = NodeInfo.nodeinfo("mobilizon.fr")
@@ -107,7 +122,12 @@ defmodule Mobilizon.Federation.NodeInfoTest do
           url: "https://event-federation.eu/.well-known/nodeinfo"
         },
         _opts ->
-          {:ok, %Tesla.Env{status: 200, body: nodeinfo_end_point_data}}
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: nodeinfo_end_point_data,
+             headers: [{"content-type", "application/json"}]
+           }}
       end)
 
       WebfingerClientMock
@@ -117,7 +137,12 @@ defmodule Mobilizon.Federation.NodeInfoTest do
           url: "https://event-federation.eu/wp-json/activitypub/1.0/nodeinfo"
         },
         _opts ->
-          {:ok, %Tesla.Env{status: 200, body: nodeinfo_wp_data}}
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: nodeinfo_wp_data,
+             headers: [{"content-type", "application/json"}]
+           }}
       end)
 
       assert {:ok, data} = NodeInfo.nodeinfo("event-federation.eu")
@@ -138,7 +163,12 @@ defmodule Mobilizon.Federation.NodeInfoTest do
           url: "https://somewhere.tld/.well-known/nodeinfo"
         },
         _opts ->
-          {:ok, %Tesla.Env{status: 200, body: nodeinfo_end_point_data}}
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: nodeinfo_end_point_data,
+             headers: [{"content-type", "application/json"}]
+           }}
       end)
 
       assert {:error, :no_node_info_endpoint_found} = NodeInfo.nodeinfo("somewhere.tld")
@@ -169,7 +199,12 @@ defmodule Mobilizon.Federation.NodeInfoTest do
           url: "https://mobilizon.fr/.well-known/nodeinfo"
         },
         _opts ->
-          {:ok, %Tesla.Env{status: 200, body: nodeinfo_end_point_data}}
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: nodeinfo_end_point_data,
+             headers: [{"content-type", "application/json"}]
+           }}
       end)
 
       WebfingerClientMock
diff --git a/test/service/workers/refresh_instances_test.exs b/test/service/workers/refresh_instances_test.exs
index 0a5181238..0948b4740 100644
--- a/test/service/workers/refresh_instances_test.exs
+++ b/test/service/workers/refresh_instances_test.exs
@@ -5,7 +5,6 @@ defmodule Mobilizon.Service.Workers.RefreshInstancesTest do
 
   alias Mobilizon.Actors.Actor
   alias Mobilizon.Federation.ActivityPub.Relay
-  alias Mobilizon.Instances.Instance
   alias Mobilizon.Service.Workers.RefreshInstances
 
   use Mobilizon.DataCase
@@ -14,7 +13,7 @@ defmodule Mobilizon.Service.Workers.RefreshInstancesTest do
     test "unless if local actor" do
       # relay = Mobilizon.Web.Relay.get_actor()
       assert {:error, :not_remote_instance} ==
-               RefreshInstances.refresh_instance_actor(%Instance{domain: nil})
+               RefreshInstances.refresh_instance_actor(nil)
     end
 
     test "unless if local relay actor" do
@@ -22,7 +21,7 @@ defmodule Mobilizon.Service.Workers.RefreshInstancesTest do
       %URI{host: domain} = URI.new!(url)
 
       assert {:error, :not_remote_instance} ==
-               RefreshInstances.refresh_instance_actor(%Instance{domain: domain})
+               RefreshInstances.refresh_instance_actor(domain)
     end
   end
 end