diff --git a/CHANGELOG.md b/CHANGELOG.md
index f7a372e11..1ec6c11cc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -41,6 +41,12 @@ switched to a new configuration mechanism, however it was not officially removed
 ### Added
 - Rich media failure tracking (along with `:failure_backoff` option).
 
+<details>
+  <summary>Admin API Changes</summary>
+
+- Add `PATCH /api/pleroma/admin/instance_document/:document_name` to modify the Terms of Service and Instance Panel HTML pages via Admin API
+</details>
+
 ### Fixed
 - Default HTTP adapter not respecting pool setting, leading to possible OOM.
 - Fixed uploading webp images when the Exiftool Upload Filter is enabled by skipping them
diff --git a/docs/API/admin_api.md b/docs/API/admin_api.md
index bc96abbf0..eba92dd1f 100644
--- a/docs/API/admin_api.md
+++ b/docs/API/admin_api.md
@@ -1455,3 +1455,45 @@ Loads json generated from `config/descriptions.exs`.
   "unread": false
 }
 ```
+
+## `GET /api/pleroma/admin/instance_document/:document_name`
+
+### Gets an instance document
+
+- Authentication: required
+
+- Response:
+
+``` json
+{
+  "url": "https://example.com/instance/panel.html"
+}
+```
+
+## `PATCH /api/pleroma/admin/instance_document/:document_name`
+- Params:
+  - `file` (the file to be uploaded, using multipart form data.)
+
+### Updates an instance document
+
+- Authentication: required
+
+- Response:
+
+``` json
+{
+  "url": "https://example.com/instance/panel.html"
+}
+```
+
+## `DELETE /api/pleroma/admin/instance_document/:document_name`
+
+### Delete an instance document
+
+- Response:
+
+``` json
+{
+  "url": "https://example.com/instance/panel.html"
+}
+```
diff --git a/lib/pleroma/web/admin_api/controllers/instance_document_controller.ex b/lib/pleroma/web/admin_api/controllers/instance_document_controller.ex
new file mode 100644
index 000000000..2144e44ac
--- /dev/null
+++ b/lib/pleroma/web/admin_api/controllers/instance_document_controller.ex
@@ -0,0 +1,37 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.AdminAPI.InstanceDocumentController do
+  use Pleroma.Web, :controller
+
+  alias Pleroma.Plugs.OAuthScopesPlug
+  alias Pleroma.Web.InstanceDocument
+
+  plug(Pleroma.Web.ApiSpec.CastAndValidate)
+
+  action_fallback(Pleroma.Web.AdminAPI.FallbackController)
+
+  defdelegate open_api_operation(action), to: Pleroma.Web.ApiSpec.Admin.InstanceDocumentOperation
+
+  plug(OAuthScopesPlug, %{scopes: ["read"], admin: true} when action == :show)
+  plug(OAuthScopesPlug, %{scopes: ["write"], admin: true} when action in [:update, :delete])
+
+  def show(conn, %{name: document_name}) do
+    with {:ok, url} <- InstanceDocument.get(document_name) do
+      json(conn, %{"url" => url})
+    end
+  end
+
+  def update(%{body_params: %{file: file}} = conn, %{name: document_name}) do
+    with {:ok, url} <- InstanceDocument.put(document_name, file.path) do
+      json(conn, %{"url" => url})
+    end
+  end
+
+  def delete(conn, %{name: document_name}) do
+    with :ok <- InstanceDocument.delete(document_name) do
+      json(conn, %{})
+    end
+  end
+end
diff --git a/lib/pleroma/web/api_spec/operations/admin/instance_document_operation.ex b/lib/pleroma/web/api_spec/operations/admin/instance_document_operation.ex
new file mode 100644
index 000000000..e0eb993fb
--- /dev/null
+++ b/lib/pleroma/web/api_spec/operations/admin/instance_document_operation.ex
@@ -0,0 +1,108 @@
+# 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.Admin.InstanceDocumentOperation do
+  alias OpenApiSpex.Operation
+  alias OpenApiSpex.Schema
+  alias Pleroma.Web.ApiSpec.Helpers
+  alias Pleroma.Web.ApiSpec.Schemas.ApiError
+
+  def open_api_operation(action) do
+    operation = String.to_existing_atom("#{action}_operation")
+    apply(__MODULE__, operation, [])
+  end
+
+  def show_operation do
+    %Operation{
+      tags: ["Admin", "InstanceDocument"],
+      summary: "Get the instance document",
+      operationId: "AdminAPI.InstanceDocumentController.show",
+      security: [%{"oAuth" => ["read"]}],
+      parameters: [
+        Operation.parameter(:name, :path, %Schema{type: :string}, "The document name",
+          required: true
+        )
+        | Helpers.admin_api_params()
+      ],
+      responses: %{
+        200 => Operation.response("InstanceDocument", "application/json", instance_document()),
+        400 => Operation.response("Bad Request", "application/json", ApiError),
+        403 => Operation.response("Forbidden", "application/json", ApiError),
+        404 => Operation.response("Not Found", "application/json", ApiError)
+      }
+    }
+  end
+
+  def update_operation do
+    %Operation{
+      tags: ["Admin", "InstanceDocument"],
+      summary: "Update the instance document",
+      operationId: "AdminAPI.InstanceDocumentController.update",
+      security: [%{"oAuth" => ["write"]}],
+      requestBody: Helpers.request_body("Parameters", update_request()),
+      parameters: [
+        Operation.parameter(:name, :path, %Schema{type: :string}, "The document name",
+          required: true
+        )
+        | Helpers.admin_api_params()
+      ],
+      responses: %{
+        200 => Operation.response("InstanceDocument", "application/json", instance_document()),
+        400 => Operation.response("Bad Request", "application/json", ApiError),
+        403 => Operation.response("Forbidden", "application/json", ApiError),
+        404 => Operation.response("Not Found", "application/json", ApiError)
+      }
+    }
+  end
+
+  defp update_request do
+    %Schema{
+      title: "UpdateRequest",
+      description: "POST body for uploading the file",
+      type: :object,
+      required: [:file],
+      properties: %{
+        file: %Schema{
+          type: :string,
+          format: :binary,
+          description: "The file to be uploaded, using multipart form data."
+        }
+      }
+    }
+  end
+
+  def delete_operation do
+    %Operation{
+      tags: ["Admin", "InstanceDocument"],
+      summary: "Get the instance document",
+      operationId: "AdminAPI.InstanceDocumentController.delete",
+      security: [%{"oAuth" => ["write"]}],
+      parameters: [
+        Operation.parameter(:name, :path, %Schema{type: :string}, "The document name",
+          required: true
+        )
+        | Helpers.admin_api_params()
+      ],
+      responses: %{
+        200 => Operation.response("InstanceDocument", "application/json", instance_document()),
+        400 => Operation.response("Bad Request", "application/json", ApiError),
+        403 => Operation.response("Forbidden", "application/json", ApiError),
+        404 => Operation.response("Not Found", "application/json", ApiError)
+      }
+    }
+  end
+
+  defp instance_document do
+    %Schema{
+      title: "InstanceDocument",
+      type: :object,
+      properties: %{
+        url: %Schema{type: :string}
+      },
+      example: %{
+        "url" => "https://example.com/static/terms-of-service.html"
+      }
+    }
+  end
+end
diff --git a/lib/pleroma/web/instance_document.ex b/lib/pleroma/web/instance_document.ex
new file mode 100644
index 000000000..969a44e41
--- /dev/null
+++ b/lib/pleroma/web/instance_document.ex
@@ -0,0 +1,62 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.InstanceDocument do
+  alias Pleroma.Config
+  alias Pleroma.Web.Endpoint
+
+  @instance_documents %{
+    "terms-of-service" => "/static/terms-of-service.html",
+    "instance-panel" => "/instance/panel.html"
+  }
+
+  @spec get(String.t()) :: {:ok, String.t()} | {:error, atom()}
+  def get(document_name) do
+    case Map.fetch(@instance_documents, document_name) do
+      {:ok, path} -> {:ok, Path.join(Endpoint.url(), path)}
+      _ -> {:error, :not_found}
+    end
+  end
+
+  @spec put(String.t(), String.t()) :: {:ok, String.t()} | {:error, atom()}
+  def put(document_name, origin_path) do
+    with {_, {:ok, destination_path}} <-
+           {:instance_document, Map.fetch(@instance_documents, document_name)},
+         :ok <- put_file(origin_path, destination_path) do
+      {:ok, Path.join(Endpoint.url(), destination_path)}
+    else
+      {:instance_document, :error} -> {:error, :not_found}
+      error -> error
+    end
+  end
+
+  @spec delete(String.t()) :: :ok | {:error, atom()}
+  def delete(document_name) do
+    with {_, {:ok, path}} <- {:instance_document, Map.fetch(@instance_documents, document_name)},
+         instance_static_dir_path <- instance_static_dir(path),
+         :ok <- File.rm(instance_static_dir_path) do
+      :ok
+    else
+      {:instance_document, :error} -> {:error, :not_found}
+      {:error, :enoent} -> {:error, :not_found}
+      error -> error
+    end
+  end
+
+  defp put_file(origin_path, destination_path) do
+    with destination <- instance_static_dir(destination_path),
+         {_, :ok} <- {:mkdir_p, File.mkdir_p(Path.dirname(destination))},
+         {_, {:ok, _}} <- {:copy, File.copy(origin_path, destination)} do
+      :ok
+    else
+      {error, _} -> {:error, error}
+    end
+  end
+
+  defp instance_static_dir(filename) do
+    [:instance, :static_dir]
+    |> Config.get!()
+    |> Path.join(filename)
+  end
+end
diff --git a/lib/pleroma/web/router.ex b/lib/pleroma/web/router.ex
index e4440d442..a4a58c2c4 100644
--- a/lib/pleroma/web/router.ex
+++ b/lib/pleroma/web/router.ex
@@ -182,6 +182,10 @@ defmodule Pleroma.Web.Router do
 
     get("/instances/:instance/statuses", AdminAPIController, :list_instance_statuses)
 
+    get("/instance_document/:name", InstanceDocumentController, :show)
+    patch("/instance_document/:name", InstanceDocumentController, :update)
+    delete("/instance_document/:name", InstanceDocumentController, :delete)
+
     patch("/users/confirm_email", AdminAPIController, :confirm_email)
     patch("/users/resend_confirmation_email", AdminAPIController, :resend_confirmation_email)
 
diff --git a/test/fixtures/custom_instance_panel.html b/test/fixtures/custom_instance_panel.html
new file mode 100644
index 000000000..6371a1e43
--- /dev/null
+++ b/test/fixtures/custom_instance_panel.html
@@ -0,0 +1 @@
+<h2>Custom instance panel</h2>
\ No newline at end of file
diff --git a/test/web/admin_api/controllers/instance_document_controller_test.exs b/test/web/admin_api/controllers/instance_document_controller_test.exs
new file mode 100644
index 000000000..60dcc9dff
--- /dev/null
+++ b/test/web/admin_api/controllers/instance_document_controller_test.exs
@@ -0,0 +1,112 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.AdminAPI.InstanceDocumentControllerTest do
+  use Pleroma.Web.ConnCase, async: true
+  import Pleroma.Factory
+  alias Pleroma.Config
+
+  @dir "test/tmp/instance_static"
+  @default_instance_panel ~s(<p>Welcome to <a href="https://pleroma.social" target="_blank">Pleroma!</a></p>)
+
+  setup do
+    File.mkdir_p!(@dir)
+    on_exit(fn -> File.rm_rf(@dir) end)
+  end
+
+  setup do: clear_config([:instance, :static_dir], @dir)
+
+  setup do
+    admin = insert(:user, is_admin: true)
+    token = insert(:oauth_admin_token, user: admin)
+
+    conn =
+      build_conn()
+      |> assign(:user, admin)
+      |> assign(:token, token)
+
+    {:ok, %{admin: admin, token: token, conn: conn}}
+  end
+
+  describe "GET /api/pleroma/admin/instance_document/:name" do
+    test "return the instance document url", %{conn: conn} do
+      conn = get(conn, "/api/pleroma/admin/instance_document/instance-panel")
+
+      assert %{"url" => url} = json_response_and_validate_schema(conn, 200)
+      index = get(build_conn(), url)
+      response = html_response(index, 200)
+      assert String.contains?(response, @default_instance_panel)
+    end
+
+    test "it returns 403 if requested by a non-admin" do
+      non_admin_user = insert(:user)
+      token = insert(:oauth_token, user: non_admin_user)
+
+      conn =
+        build_conn()
+        |> assign(:user, non_admin_user)
+        |> assign(:token, token)
+        |> get("/api/pleroma/admin/instance_document/instance-panel")
+
+      assert json_response(conn, :forbidden)
+    end
+
+    test "it returns 404 if the instance document with the given name doesn't exist", %{
+      conn: conn
+    } do
+      conn = get(conn, "/api/pleroma/admin/instance_document/1234")
+
+      assert json_response_and_validate_schema(conn, 404)
+    end
+  end
+
+  describe "PATCH /api/pleroma/admin/instance_document/:name" do
+    test "uploads the instance document", %{conn: conn} do
+      image = %Plug.Upload{
+        content_type: "text/html",
+        path: Path.absname("test/fixtures/custom_instance_panel.html"),
+        filename: "custom_instance_panel.html"
+      }
+
+      conn =
+        conn
+        |> put_req_header("content-type", "multipart/form-data")
+        |> patch("/api/pleroma/admin/instance_document/instance-panel", %{
+          "file" => image
+        })
+
+      assert %{"url" => url} = json_response_and_validate_schema(conn, 200)
+      index = get(build_conn(), url)
+      assert html_response(index, 200) == "<h2>Custom instance panel</h2>"
+    end
+  end
+
+  describe "DELETE /api/pleroma/admin/instance_document/:name" do
+    test "deletes the instance document", %{conn: conn} do
+      File.mkdir!(@dir <> "/instance/")
+      File.write!(@dir <> "/instance/panel.html", "Custom instance panel")
+
+      conn_resp =
+        conn
+        |> get("/api/pleroma/admin/instance_document/instance-panel")
+
+      assert %{"url" => url} = json_response_and_validate_schema(conn_resp, 200)
+      index = get(build_conn(), url)
+      assert html_response(index, 200) == "Custom instance panel"
+
+      conn
+      |> delete("/api/pleroma/admin/instance_document/instance-panel")
+      |> json_response_and_validate_schema(200)
+
+      conn_resp =
+        conn
+        |> get("/api/pleroma/admin/instance_document/instance-panel")
+
+      assert %{"url" => url} = json_response_and_validate_schema(conn_resp, 200)
+      index = get(build_conn(), url)
+      response = html_response(index, 200)
+      assert String.contains?(response, @default_instance_panel)
+    end
+  end
+end