diff --git a/lib/micropub/models/post_json_parser.rb b/lib/micropub/models/post_json_parser.rb
new file mode 100644
index 0000000..d005a86
--- /dev/null
+++ b/lib/micropub/models/post_json_parser.rb
@@ -0,0 +1,38 @@
+class PostJSONParser
+  def initialize(json)
+    @data = JSON.parse(json)
+  end
+
+  def params
+    {
+      "title" => title,
+      "content" => content,
+      "category" => category,
+    }.compact
+  end
+
+  private
+
+  attr_accessor :data
+
+  def title
+    data.dig("properties", "title", 0)
+  end
+
+  def content
+    data.dig("properties", "content", 0) || nested_content
+  end
+
+  def nested_content
+    text = data.dig("properties", "content", "text", 0)
+    html = data.dig("properties", "content", "html", 0)
+
+    return nil if text.nil? && html.nil?
+
+    { "text" => text, "html" => html }.compact
+  end
+
+  def category
+    data.dig("properties", "category")
+  end
+end
diff --git a/lib/micropub/webserver.rb b/lib/micropub/webserver.rb
index b706f7b..9c76416 100644
--- a/lib/micropub/webserver.rb
+++ b/lib/micropub/webserver.rb
@@ -41,13 +41,17 @@ module Micropub
 
     def post_params
       if request.env["CONTENT_TYPE"] == "application/json"
-        request.body.rewind
-        JSON.parse(request.body.read)
+        json_params
       else
         params
       end
     end
 
+    def json_params
+      request.body.rewind
+      PostJSONParser.new(request.body.read).params
+    end
+
     def valid_token?
       token = Indieauth::Token.new(endpoints.token_endpoint)
 
diff --git a/test/lib/micropub/models/post_json_parser_test.rb b/test/lib/micropub/models/post_json_parser_test.rb
new file mode 100644
index 0000000..e7a84d0
--- /dev/null
+++ b/test/lib/micropub/models/post_json_parser_test.rb
@@ -0,0 +1,79 @@
+require "test_helper"
+
+require "micropub/models/post_json_parser"
+
+describe PostJSONParser do
+  describe "#params" do
+    it "parses basic attributes" do
+      json = <<~JS
+        {
+          "type": ["h-entry"],
+          "properties": {
+            "content": ["Hello, World!"]
+          }
+        }
+      JS
+
+      parser = PostJSONParser.new(json)
+
+      _(parser.params).must_equal(
+        { "content" => "Hello, World!" }
+      )
+    end
+
+    it "parses content with nested text" do
+      json = <<~JS
+        {
+          "type": ["h-entry"],
+          "properties": {
+            "content": {
+              "text": ["Hello, World!"]
+            }
+          }
+        }
+      JS
+
+      parser = PostJSONParser.new(json)
+
+      _(parser.params).must_equal(
+        { "content" => { "text" => "Hello, World!" } }
+      )
+    end
+
+    it "parses content with nested html" do
+      json = <<~JS
+        {
+          "type": ["h-entry"],
+          "properties": {
+            "content": {
+              "html": ["<p>Hello, World!</p>"]
+            }
+          }
+        }
+      JS
+
+      parser = PostJSONParser.new(json)
+
+      _(parser.params).must_equal(
+        { "content" => { "html" => "<p>Hello, World!</p>" } }
+      )
+    end
+
+    it "parses a single category" do
+      json = <<~JS
+        {
+          "type": ["h-entry"],
+          "properties": {
+            "category": ["test"]
+          }
+        }
+      JS
+
+      parser = PostJSONParser.new(json)
+
+      _(parser.params).must_equal(
+        { "category" => ["test"] }
+      )
+    end
+  end
+end
diff --git a/test/requests/create_post_test.rb b/test/requests/create_post_test.rb
index 3b5faf0..f238ff6 100644
--- a/test/requests/create_post_test.rb
+++ b/test/requests/create_post_test.rb
@@ -62,8 +62,11 @@ describe "create post" do
 
   it "creates a post with JSON" do
     post_json = {
-      content: "Hello, World!",
-      category: ["one", "two", "three"],
+      type: "h-entry",
+      properties: {
+        content: ["Hello, World!"],
+        category: ["one", "two", "three"],
+      },
     }.to_json
 
     post "/micropub/main", post_json, { "CONTENT_TYPE" => "application/json" }
@@ -76,8 +79,11 @@ describe "create post" do
 
   it "creates a post with JSON and HTML content" do
     post_json = {
-      content: { html: "<p>Hello, World!</p>" },
-      category: ["one", "two", "three"],
+      type: "h-entry",
+      properties: {
+        content: { html: ["<p>Hello, World!</p>"] },
+        category: ["one", "two", "three"],
+      },
     }.to_json
 
     post "/micropub/main", post_json, { "CONTENT_TYPE" => "application/json" }