diff --git a/Gemfile b/Gemfile
index bf48e21..8e8404f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,20 +4,18 @@ ruby "2.6.5"
 
 gem "dotenv"
 
+gem "faraday"
+gem "github_api"
+gem "indieweb-endpoints"
+gem "kramdown"
+gem "puma"
 gem "sinatra"
 gem "sinatra-contrib"
-gem "puma"
-
-gem "faraday"
-
-gem "github_api"
-
-gem "indieweb-endpoints"
 
 group :test do
-  gem "pry"
   gem "minitest"
   gem "minitest-hooks"
   gem "mocha"
+  gem "pry"
   gem "rack-test"
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index ba6571c..d943728 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -42,6 +42,7 @@ GEM
       link-header-parser (~> 0.2.0)
       nokogiri (~> 1.10)
     jwt (2.2.1)
+    kramdown (2.1.0)
     link-header-parser (0.2.0)
       absolutely (~> 3.0)
     metaclass (0.0.4)
@@ -103,6 +104,7 @@ DEPENDENCIES
   faraday
   github_api
   indieweb-endpoints
+  kramdown
   minitest
   minitest-hooks
   mocha
diff --git a/bin/kramdown b/bin/kramdown
new file mode 100755
index 0000000..73320ec
--- /dev/null
+++ b/bin/kramdown
@@ -0,0 +1,29 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+#
+# This file was generated by Bundler.
+#
+# The application 'kramdown' is installed as part of a gem, and
+# this file is here to facilitate running it.
+#
+
+require "pathname"
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile",
+  Pathname.new(__FILE__).realpath)
+
+bundle_binstub = File.expand_path("../bundle", __FILE__)
+
+if File.file?(bundle_binstub)
+  if File.read(bundle_binstub, 300) =~ /This file was generated by Bundler/
+    load(bundle_binstub)
+  else
+    abort("Your `bin/bundle` was not generated by Bundler, so this binstub cannot run.
+Replace `bin/bundle` by running `bundle binstubs bundler --force`, then run this command again.")
+  end
+end
+
+require "rubygems"
+require "bundler/setup"
+
+load Gem.bin_path("kramdown", "kramdown")
diff --git a/lib/micropub/models/post.rb b/lib/micropub/models/post.rb
index 36893fb..9109c78 100644
--- a/lib/micropub/models/post.rb
+++ b/lib/micropub/models/post.rb
@@ -1,4 +1,5 @@
 require "date"
+require "kramdown"
 
 class Post
   attr_accessor :params
@@ -48,7 +49,21 @@ class Post
   end
 
   def content
-    params["content"]
+    if params["content"].is_a?(Hash)
+      content_from_hash
+    else
+      params["content"]
+    end
+  end
+
+  def content_from_hash
+    if params["content"]["text"]
+      params["content"]["text"]
+    elsif params["content"]["html"]
+      Kramdown::Document.
+        new(params["content"]["html"], html_to_native: true).
+        to_kramdown
+    end
   end
 
   def post_content
diff --git a/test/lib/micropub/models/post_test.rb b/test/lib/micropub/models/post_test.rb
index d79a698..8686adc 100644
--- a/test/lib/micropub/models/post_test.rb
+++ b/test/lib/micropub/models/post_test.rb
@@ -130,6 +130,18 @@ describe Post do
 
       _(post.content).must_equal "Hello, World!"
     end
+
+    it "accepts content in an object" do
+      post = Post.new("content" => { "text" => "Hello, World!" })
+
+      _(post.content).must_equal "Hello, World!"
+    end
+
+    it "converts HTML content to Markdown" do
+      post = Post.new("content" => { "html" => "<p>Hello, World!</p>" })
+
+      _(post.content.strip).must_equal "Hello, World!"
+    end
   end
 
   describe "#post_content" do
diff --git a/test/requests/create_post_test.rb b/test/requests/create_post_test.rb
index 4adb149..3b5faf0 100644
--- a/test/requests/create_post_test.rb
+++ b/test/requests/create_post_test.rb
@@ -73,4 +73,18 @@ describe "create post" do
     assert_equal last_response.headers["Location"],
       "https://test.danbarber.me/blog/#{date}/hello-world"
   end
+
+  it "creates a post with JSON and HTML content" do
+    post_json = {
+      content: { html: "<p>Hello, World!</p>" },
+      category: ["one", "two", "three"],
+    }.to_json
+
+    post "/micropub/main", post_json, { "CONTENT_TYPE" => "application/json" }
+
+    date = Time.now.strftime("%Y/%m/%d")
+    assert last_response.accepted?
+    assert_equal last_response.headers["Location"],
+      "https://test.danbarber.me/blog/#{date}/hello-world"
+  end
 end