diff --git a/README.md b/README.md
index 18304ad..9991f96 100644
--- a/README.md
+++ b/README.md
@@ -8,3 +8,11 @@ Use [@apidevtools/json-schema-ref-parser](https://github.com/APIDevTools/json-sc
 ToDo
 ### Convert string to int for int32 type in `.proto`
 ToDo
+
+### Import markown files
+
+Embed external Markdown file contents to the `info.description` auto-generated JSON file. See [Redoc documentation](https://redocly.com/docs/api-reference-docs/guides/embedded-markdown/) for more information.
+
+### Add x-logo
+
+[`x-logo`](https://github.com/Redocly/redoc/blob/master/docs/redoc-vendor-extensions.md#x-logo) is a [vendor extension](https://swagger.io/specification/#specificationExtensions) from Redoc. It allows you to show a custom logo on the left upper corner of your redoc output.
diff --git a/src/addlogo.js b/src/addlogo.js
new file mode 100644
index 0000000..1647d13
--- /dev/null
+++ b/src/addlogo.js
@@ -0,0 +1,15 @@
+const fs = require("fs");
+
+function addLogo(file, url, alt, href) {
+  const schema = JSON.parse(fs.readFileSync(file, 'utf8'));
+  schema["info"]["x-logo"] = {
+      "url": url,
+      "backgroundColor": "#FFFFFF",
+      "altText": alt,
+      "href": href,
+  };
+  fs.writeFileSync(file, JSON.stringify(schema, null, 2));
+  console.log(`Add logo to ${file}`);
+}
+
+module.exports = addLogo;
diff --git a/src/main.js b/src/main.js
index 03b9a69..b3ad8e9 100644
--- a/src/main.js
+++ b/src/main.js
@@ -2,6 +2,7 @@ const { Command } = require("commander");
 
 const deref = require("./deref.js");
 const importMd = require("./importmd.js");
+const addLogo = require("./addlogo.js");
 
 const program = new Command();
 program
@@ -13,10 +14,17 @@ program.command("deref")
     .argument("<in-filename>", "Input JSON file")
     .argument("[out-filename]", "Output JSON file. If not specified, use in-filename.")
     .action(deref);
-program.command("importMd")
+program.command("importmd")
     .description("Add a markdown $Ref to JSON info.description")
     .argument("<in-filename>", "Target JSON file")
     .argument("<path>", "markdown path to ref")
     .action(importMd);
+program.command("addlogo")
+    .description("Add a logo to JSON info.x-logo")
+    .argument("<in-filename>", "Target JSON file")
+    .argument("<url>", "Logo absolute url")
+    .argument("<alt>", "Logo alt text")
+    .argument("<href>", "Logo href")
+    .action(addLogo);
 
 program.parse();