diff --git a/docs/API/pleroma_api.md b/docs/API/pleroma_api.md
index 867f59919..d6dbafc06 100644
--- a/docs/API/pleroma_api.md
+++ b/docs/API/pleroma_api.md
@@ -358,7 +358,7 @@ The status posting endpoint takes an additional parameter, `in_reply_to_conversa
     * `recipients`: A list of ids of users that should receive posts to this conversation. This will replace the current list of recipients, so submit the full list. The owner of owner of the conversation will always be part of the set of recipients, though.
 * Response: JSON, statuses (200 - healthy, 503 unhealthy)
 
-## `GET /api/v1/pleroma/conversations/read`
+## `POST /api/v1/pleroma/conversations/read`
 ### Marks all user's conversations as read.
 * Method `POST`
 * Authentication: required
@@ -536,7 +536,7 @@ Emoji reactions work a lot like favourites do. They make it possible to react to
 ```
 
 ## `GET /api/v1/pleroma/statuses/:id/reactions/:emoji`
-### Get an object of emoji to account mappings with accounts that reacted to the post for a specific emoji`
+### Get an object of emoji to account mappings with accounts that reacted to the post for a specific emoji
 * Method: `GET`
 * Authentication: optional
 * Params: None
diff --git a/lib/pleroma/web/api_spec/operations/notification_operation.ex b/lib/pleroma/web/api_spec/operations/notification_operation.ex
index 64adc5319..46e72f8bf 100644
--- a/lib/pleroma/web/api_spec/operations/notification_operation.ex
+++ b/lib/pleroma/web/api_spec/operations/notification_operation.ex
@@ -145,7 +145,7 @@ def destroy_multiple_operation do
     }
   end
 
-  defp notification do
+  def notification do
     %Schema{
       title: "Notification",
       description: "Response schema for a notification",
diff --git a/lib/pleroma/web/api_spec/operations/pleroma_operation.ex b/lib/pleroma/web/api_spec/operations/pleroma_operation.ex
new file mode 100644
index 000000000..c6df5c854
--- /dev/null
+++ b/lib/pleroma/web/api_spec/operations/pleroma_operation.ex
@@ -0,0 +1,223 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ApiSpec.PleromaOperation do
+  alias OpenApiSpex.Operation
+  alias OpenApiSpex.Schema
+  alias Pleroma.Web.ApiSpec.Schemas.Account
+  alias Pleroma.Web.ApiSpec.Schemas.ApiError
+  alias Pleroma.Web.ApiSpec.Schemas.FlakeID
+  alias Pleroma.Web.ApiSpec.Schemas.Status
+  alias Pleroma.Web.ApiSpec.Schemas.Conversation
+  alias Pleroma.Web.ApiSpec.StatusOperation
+  alias Pleroma.Web.ApiSpec.NotificationOperation
+
+  import Pleroma.Web.ApiSpec.Helpers
+
+  def open_api_operation(action) do
+    operation = String.to_existing_atom("#{action}_operation")
+    apply(__MODULE__, operation, [])
+  end
+
+  def emoji_reactions_by_operation do
+    %Operation{
+      tags: ["Emoji Reactions"],
+      summary:
+        "Get an object of emoji to account mappings with accounts that reacted to the post",
+      parameters: [
+        Operation.parameter(:id, :path, FlakeID, "Status ID", required: true),
+        Operation.parameter(:emoji, :path, :string, "Filter by a single unicode emoji",
+          required: false
+        )
+      ],
+      security: [%{"oAuth" => ["read:statuses"]}],
+      operationId: "PleromaController.emoji_reactions_by",
+      responses: %{
+        200 => array_of_reactions_response()
+      }
+    }
+  end
+
+  def react_with_emoji_operation do
+    %Operation{
+      tags: ["Emoji Reactions"],
+      summary: "React to a post with a unicode emoji",
+      parameters: [
+        Operation.parameter(:id, :path, FlakeID, "Status ID", required: true),
+        Operation.parameter(:emoji, :path, :string, "A single character unicode emoji",
+          required: true
+        )
+      ],
+      security: [%{"oAuth" => ["write:statuses"]}],
+      operationId: "PleromaController.react_with_emoji",
+      responses: %{
+        200 => Operation.response("Status", "application/json", Status)
+      }
+    }
+  end
+
+  def unreact_with_emoji_operation do
+    %Operation{
+      tags: ["Emoji Reactions"],
+      summary: "Remove a reaction to a post with a unicode emoji",
+      parameters: [
+        Operation.parameter(:id, :path, FlakeID, "Status ID", required: true),
+        Operation.parameter(:emoji, :path, :string, "A single character unicode emoji",
+          required: true
+        )
+      ],
+      security: [%{"oAuth" => ["write:statuses"]}],
+      operationId: "PleromaController.unreact_with_emoji",
+      responses: %{
+        200 => Operation.response("Status", "application/json", Status)
+      }
+    }
+  end
+
+  defp array_of_reactions_response do
+    Operation.response("Array of Emoji Reactions", "application/json", %Schema{
+      type: :array,
+      items: emoji_reaction(),
+      example: [emoji_reaction().example]
+    })
+  end
+
+  defp emoji_reaction do
+    %Schema{
+      title: "EmojiReaction",
+      type: :object,
+      properties: %{
+        name: %Schema{type: :string, description: "Emoji"},
+        count: %Schema{type: :integer, description: "Count of reactions with this emoji"},
+        me: %Schema{type: :boolean, description: "Did I react with this emoji?"},
+        accounts: %Schema{
+          type: :array,
+          items: Account,
+          description: "Array of accounts reacted with this emoji"
+        }
+      },
+      example: %{
+        "name" => "😱",
+        "count" => 1,
+        "me" => false,
+        "accounts" => [Account.schema().example]
+      }
+    }
+  end
+
+  def conversation_operation do
+    %Operation{
+      tags: ["Conversations"],
+      summary: "The conversation with the given ID",
+      parameters: [
+        Operation.parameter(:id, :path, :string, "Conversation ID",
+          example: "123",
+          required: true
+        )
+      ],
+      security: [%{"oAuth" => ["read:statuses"]}],
+      operationId: "PleromaController.conversation",
+      responses: %{
+        200 => Operation.response("Conversation", "application/json", Conversation)
+      }
+    }
+  end
+
+  def conversation_statuses_operation do
+    %Operation{
+      tags: ["Conversations"],
+      summary: "Timeline for a given conversation",
+      parameters: [
+        Operation.parameter(:id, :path, :string, "Conversation ID",
+          example: "123",
+          required: true
+        )
+        | pagination_params()
+      ],
+      security: [%{"oAuth" => ["read:statuses"]}],
+      operationId: "PleromaController.conversation_statuses",
+      responses: %{
+        200 =>
+          Operation.response(
+            "Array of Statuses",
+            "application/json",
+            StatusOperation.array_of_statuses()
+          )
+      }
+    }
+  end
+
+  def update_conversation_operation do
+    %Operation{
+      tags: ["Conversations"],
+      summary: "Update a conversation. Used to change the set of recipients.",
+      parameters: [
+        Operation.parameter(:id, :path, :string, "Conversation ID",
+          example: "123",
+          required: true
+        ),
+        Operation.parameter(
+          :recipients,
+          :query,
+          %Schema{type: :array, items: FlakeID},
+          "A list of ids of users that should receive posts to this conversation. This will replace the current list of recipients, so submit the full list. The owner of owner of the conversation will always be part of the set of recipients, though.",
+          required: true
+        )
+      ],
+      security: [%{"oAuth" => ["write:conversations"]}],
+      operationId: "PleromaController.update_conversation",
+      responses: %{
+        200 => Operation.response("Conversation", "application/json", Conversation)
+      }
+    }
+  end
+
+  def mark_conversations_as_read_operation do
+    %Operation{
+      tags: ["Conversations"],
+      summary: "Marks all user's conversations as read",
+      security: [%{"oAuth" => ["write:conversations"]}],
+      operationId: "PleromaController.mark_conversations_as_read",
+      responses: %{
+        200 =>
+          Operation.response(
+            "Array of Conversations that were marked as read",
+            "application/json",
+            %Schema{
+              type: :array,
+              items: Conversation,
+              example: [Conversation.schema().example]
+            }
+          )
+      }
+    }
+  end
+
+  def mark_notifications_as_read_operation do
+    %Operation{
+      tags: ["Notifications"],
+      summary: "Mark notifications as read. Query parameters are mutually exclusive.",
+      parameters: [
+        Operation.parameter(:id, :query, :string, "A single notification ID to read"),
+        Operation.parameter(:max_id, :query, :string, "Read all notifications up to this id")
+      ],
+      security: [%{"oAuth" => ["write:notifications"]}],
+      operationId: "PleromaController.mark_notifications_as_read",
+      responses: %{
+        200 =>
+          Operation.response(
+            "A Notification or array of Motifications",
+            "application/json",
+            %Schema{
+              anyOf: [
+                %Schema{type: :array, items: NotificationOperation.notification()},
+                NotificationOperation.notification()
+              ]
+            }
+          ),
+        400 => Operation.response("Bad Request", "application/json", ApiError)
+      }
+    }
+  end
+end
diff --git a/lib/pleroma/web/pleroma_api/controllers/pleroma_api_controller.ex b/lib/pleroma/web/pleroma_api/controllers/pleroma_api_controller.ex
index e834133b2..8220d13bc 100644
--- a/lib/pleroma/web/pleroma_api/controllers/pleroma_api_controller.ex
+++ b/lib/pleroma/web/pleroma_api/controllers/pleroma_api_controller.ex
@@ -20,6 +20,8 @@ defmodule Pleroma.Web.PleromaAPI.PleromaAPIController do
   alias Pleroma.Web.MastodonAPI.NotificationView
   alias Pleroma.Web.MastodonAPI.StatusView
 
+  plug(Pleroma.Web.ApiSpec.CastAndValidate)
+
   plug(
     OAuthScopesPlug,
     %{scopes: ["read:statuses"]}
@@ -49,14 +51,16 @@ defmodule Pleroma.Web.PleromaAPI.PleromaAPIController do
     %{scopes: ["write:notifications"]} when action == :mark_notifications_as_read
   )
 
-  def emoji_reactions_by(%{assigns: %{user: user}} = conn, %{"id" => activity_id} = params) do
+  defdelegate open_api_operation(action), to: Pleroma.Web.ApiSpec.PleromaOperation
+
+  def emoji_reactions_by(%{assigns: %{user: user}} = conn, %{id: activity_id} = params) do
     with %Activity{} = activity <- Activity.get_by_id_with_object(activity_id),
          %Object{data: %{"reactions" => emoji_reactions}} when is_list(emoji_reactions) <-
            Object.normalize(activity) do
       reactions =
         emoji_reactions
         |> Enum.map(fn [emoji, user_ap_ids] ->
-          if params["emoji"] && params["emoji"] != emoji do
+          if params[:emoji] && params[:emoji] != emoji do
             nil
           else
             users =
@@ -79,7 +83,7 @@ def emoji_reactions_by(%{assigns: %{user: user}} = conn, %{"id" => activity_id}
             }
           end
         end)
-        |> Enum.filter(& &1)
+        |> Enum.reject(&is_nil/1)
 
       conn
       |> json(reactions)
@@ -90,7 +94,7 @@ def emoji_reactions_by(%{assigns: %{user: user}} = conn, %{"id" => activity_id}
     end
   end
 
-  def react_with_emoji(%{assigns: %{user: user}} = conn, %{"id" => activity_id, "emoji" => emoji}) do
+  def react_with_emoji(%{assigns: %{user: user}} = conn, %{id: activity_id, emoji: emoji}) do
     with {:ok, _activity} <- CommonAPI.react_with_emoji(activity_id, user, emoji),
          activity <- Activity.get_by_id(activity_id) do
       conn
@@ -99,10 +103,7 @@ def react_with_emoji(%{assigns: %{user: user}} = conn, %{"id" => activity_id, "e
     end
   end
 
-  def unreact_with_emoji(%{assigns: %{user: user}} = conn, %{
-        "id" => activity_id,
-        "emoji" => emoji
-      }) do
+  def unreact_with_emoji(%{assigns: %{user: user}} = conn, %{id: activity_id, emoji: emoji}) do
     with {:ok, _activity} <-
            CommonAPI.unreact_with_emoji(activity_id, user, emoji),
          activity <- Activity.get_by_id(activity_id) do
@@ -112,7 +113,7 @@ def unreact_with_emoji(%{assigns: %{user: user}} = conn, %{
     end
   end
 
-  def conversation(%{assigns: %{user: user}} = conn, %{"id" => participation_id}) do
+  def conversation(%{assigns: %{user: user}} = conn, %{id: participation_id}) do
     with %Participation{} = participation <- Participation.get(participation_id),
          true <- user.id == participation.user_id do
       conn
@@ -128,12 +129,13 @@ def conversation(%{assigns: %{user: user}} = conn, %{"id" => participation_id})
 
   def conversation_statuses(
         %{assigns: %{user: %{id: user_id} = user}} = conn,
-        %{"id" => participation_id} = params
+        %{id: participation_id} = params
       ) do
     with %Participation{user_id: ^user_id} = participation <-
            Participation.get(participation_id, preload: [:conversation]) do
       params =
         params
+        |> Map.new(fn {key, value} -> {to_string(key), value} end)
         |> Map.put("blocking_user", user)
         |> Map.put("muting_user", user)
         |> Map.put("user", user)
@@ -162,7 +164,7 @@ def conversation_statuses(
 
   def update_conversation(
         %{assigns: %{user: user}} = conn,
-        %{"id" => participation_id, "recipients" => recipients}
+        %{id: participation_id, recipients: recipients}
       ) do
     with %Participation{} = participation <- Participation.get(participation_id),
          true <- user.id == participation.user_id,
@@ -192,7 +194,7 @@ def mark_conversations_as_read(%{assigns: %{user: user}} = conn, _params) do
     end
   end
 
-  def mark_notifications_as_read(%{assigns: %{user: user}} = conn, %{"id" => notification_id}) do
+  def mark_notifications_as_read(%{assigns: %{user: user}} = conn, %{id: notification_id}) do
     with {:ok, notification} <- Notification.read_one(user, notification_id) do
       conn
       |> put_view(NotificationView)
@@ -205,7 +207,7 @@ def mark_notifications_as_read(%{assigns: %{user: user}} = conn, %{"id" => notif
     end
   end
 
-  def mark_notifications_as_read(%{assigns: %{user: user}} = conn, %{"max_id" => max_id}) do
+  def mark_notifications_as_read(%{assigns: %{user: user}} = conn, %{max_id: max_id}) do
     with notifications <- Notification.set_read_up_to(user, max_id) do
       notifications = Enum.take(notifications, 80)
 
diff --git a/test/support/api_spec_helpers.ex b/test/support/api_spec_helpers.ex
index 80c69c788..46388f92c 100644
--- a/test/support/api_spec_helpers.ex
+++ b/test/support/api_spec_helpers.ex
@@ -51,7 +51,7 @@ def api_operations do
       |> Map.take([:delete, :get, :head, :options, :patch, :post, :put, :trace])
       |> Map.values()
       |> Enum.reject(&is_nil/1)
-      |> Enum.uniq()
     end)
+    |> Enum.uniq()
   end
 end
diff --git a/test/web/pleroma_api/controllers/pleroma_api_controller_test.exs b/test/web/pleroma_api/controllers/pleroma_api_controller_test.exs
index cfd1dbd24..f0cdc2f08 100644
--- a/test/web/pleroma_api/controllers/pleroma_api_controller_test.exs
+++ b/test/web/pleroma_api/controllers/pleroma_api_controller_test.exs
@@ -27,7 +27,7 @@ test "PUT /api/v1/pleroma/statuses/:id/reactions/:emoji", %{conn: conn} do
       |> assign(:user, other_user)
       |> assign(:token, insert(:oauth_token, user: other_user, scopes: ["write:statuses"]))
       |> put("/api/v1/pleroma/statuses/#{activity.id}/reactions/☕")
-      |> json_response(200)
+      |> json_response_and_validate_schema(200)
 
     # We return the status, but this our implementation detail.
     assert %{"id" => id} = result
@@ -53,7 +53,7 @@ test "DELETE /api/v1/pleroma/statuses/:id/reactions/:emoji", %{conn: conn} do
       |> assign(:token, insert(:oauth_token, user: other_user, scopes: ["write:statuses"]))
       |> delete("/api/v1/pleroma/statuses/#{activity.id}/reactions/☕")
 
-    assert %{"id" => id} = json_response(result, 200)
+    assert %{"id" => id} = json_response_and_validate_schema(result, 200)
     assert to_string(activity.id) == id
 
     ObanHelpers.perform_all()
@@ -73,7 +73,7 @@ test "GET /api/v1/pleroma/statuses/:id/reactions", %{conn: conn} do
     result =
       conn
       |> get("/api/v1/pleroma/statuses/#{activity.id}/reactions")
-      |> json_response(200)
+      |> json_response_and_validate_schema(200)
 
     assert result == []
 
@@ -85,7 +85,7 @@ test "GET /api/v1/pleroma/statuses/:id/reactions", %{conn: conn} do
     result =
       conn
       |> get("/api/v1/pleroma/statuses/#{activity.id}/reactions")
-      |> json_response(200)
+      |> json_response_and_validate_schema(200)
 
     [%{"name" => "🎅", "count" => 1, "accounts" => [represented_user], "me" => false}] = result
 
@@ -96,7 +96,7 @@ test "GET /api/v1/pleroma/statuses/:id/reactions", %{conn: conn} do
       |> assign(:user, other_user)
       |> assign(:token, insert(:oauth_token, user: other_user, scopes: ["read:statuses"]))
       |> get("/api/v1/pleroma/statuses/#{activity.id}/reactions")
-      |> json_response(200)
+      |> json_response_and_validate_schema(200)
 
     assert [%{"name" => "🎅", "count" => 1, "accounts" => [_represented_user], "me" => true}] =
              result
@@ -111,7 +111,7 @@ test "GET /api/v1/pleroma/statuses/:id/reactions/:emoji", %{conn: conn} do
     result =
       conn
       |> get("/api/v1/pleroma/statuses/#{activity.id}/reactions/🎅")
-      |> json_response(200)
+      |> json_response_and_validate_schema(200)
 
     assert result == []
 
@@ -121,7 +121,7 @@ test "GET /api/v1/pleroma/statuses/:id/reactions/:emoji", %{conn: conn} do
     result =
       conn
       |> get("/api/v1/pleroma/statuses/#{activity.id}/reactions/🎅")
-      |> json_response(200)
+      |> json_response_and_validate_schema(200)
 
     [%{"name" => "🎅", "count" => 1, "accounts" => [represented_user], "me" => false}] = result
 
@@ -140,7 +140,7 @@ test "/api/v1/pleroma/conversations/:id" do
     result =
       conn
       |> get("/api/v1/pleroma/conversations/#{participation.id}")
-      |> json_response(200)
+      |> json_response_and_validate_schema(200)
 
     assert result["id"] == participation.id |> to_string()
   end
@@ -168,7 +168,7 @@ test "/api/v1/pleroma/conversations/:id/statuses" do
     result =
       conn
       |> get("/api/v1/pleroma/conversations/#{participation.id}/statuses")
-      |> json_response(200)
+      |> json_response_and_validate_schema(200)
 
     assert length(result) == 2
 
@@ -186,12 +186,12 @@ test "/api/v1/pleroma/conversations/:id/statuses" do
     assert [%{"id" => ^id_two}, %{"id" => ^id_three}] =
              conn
              |> get("/api/v1/pleroma/conversations/#{participation.id}/statuses?limit=2")
-             |> json_response(:ok)
+             |> json_response_and_validate_schema(:ok)
 
     assert [%{"id" => ^id_three}] =
              conn
              |> get("/api/v1/pleroma/conversations/#{participation.id}/statuses?min_id=#{id_two}")
-             |> json_response(:ok)
+             |> json_response_and_validate_schema(:ok)
   end
 
   test "PATCH /api/v1/pleroma/conversations/:id" do
@@ -208,12 +208,12 @@ test "PATCH /api/v1/pleroma/conversations/:id" do
     assert [user] == participation.recipients
     assert other_user not in participation.recipients
 
+    query = "recipients[]=#{user.id}&recipients[]=#{other_user.id}"
+
     result =
       conn
-      |> patch("/api/v1/pleroma/conversations/#{participation.id}", %{
-        "recipients" => [user.id, other_user.id]
-      })
-      |> json_response(200)
+      |> patch("/api/v1/pleroma/conversations/#{participation.id}?#{query}")
+      |> json_response_and_validate_schema(200)
 
     assert result["id"] == participation.id |> to_string
 
@@ -242,7 +242,7 @@ test "POST /api/v1/pleroma/conversations/read" do
     [%{"unread" => false}, %{"unread" => false}] =
       conn
       |> post("/api/v1/pleroma/conversations/read", %{})
-      |> json_response(200)
+      |> json_response_and_validate_schema(200)
 
     [participation2, participation1] = Participation.for_user(other_user)
     assert Participation.get(participation2.id).read == true
@@ -262,8 +262,8 @@ test "it marks a single notification as read", %{user: user1, conn: conn} do
 
       response =
         conn
-        |> post("/api/v1/pleroma/notifications/read", %{"id" => "#{notification1.id}"})
-        |> json_response(:ok)
+        |> post("/api/v1/pleroma/notifications/read?id=#{notification1.id}")
+        |> json_response_and_validate_schema(:ok)
 
       assert %{"pleroma" => %{"is_seen" => true}} = response
       assert Repo.get(Notification, notification1.id).seen
@@ -280,8 +280,8 @@ test "it marks multiple notifications as read", %{user: user1, conn: conn} do
 
       [response1, response2] =
         conn
-        |> post("/api/v1/pleroma/notifications/read", %{"max_id" => "#{notification2.id}"})
-        |> json_response(:ok)
+        |> post("/api/v1/pleroma/notifications/read?max_id=#{notification2.id}")
+        |> json_response_and_validate_schema(:ok)
 
       assert %{"pleroma" => %{"is_seen" => true}} = response1
       assert %{"pleroma" => %{"is_seen" => true}} = response2
@@ -293,8 +293,8 @@ test "it marks multiple notifications as read", %{user: user1, conn: conn} do
     test "it returns error when notification not found", %{conn: conn} do
       response =
         conn
-        |> post("/api/v1/pleroma/notifications/read", %{"id" => "22222222222222"})
-        |> json_response(:bad_request)
+        |> post("/api/v1/pleroma/notifications/read?id=22222222222222")
+        |> json_response_and_validate_schema(:bad_request)
 
       assert response == %{"error" => "Cannot get notification"}
     end