diff --git a/bin/threatdown.ts b/bin/threatdown.ts
index 4e1b253..e95e85b 100755
--- a/bin/threatdown.ts
+++ b/bin/threatdown.ts
@@ -1,18 +1,16 @@
 #!/usr/bin/env node
 import { readFileSync, writeFileSync } from "node:fs";
-import { resolve } from "node:path";
+import { extname, resolve } from "node:path";
 import { parseArgs } from "node:util";
 
 import {
   parse,
   compileToMermaid,
+  generateUpdatedMd,
   renderMermaid,
 } from "../lib";
 
-const {
-  values,
-  positionals,
-} = parseArgs({
+const { values, positionals } = parseArgs({
   allowPositionals: true,
   options: {
     output: {
@@ -27,22 +25,48 @@ const {
   },
 });
 
-function usage () {
+function usage() {
   console.log(`Usage: threatdown <filename>
 
+  <filename>         Must have extension \`.td\` or \`.md\`
   --output <output>  Write result to file <output>
   --type <type>      Change output type, must be one of "json", "mermaid" or "svg"
 `);
 }
 
-async function main () {
-  const inputFile = positionals.shift();
+async function main() {
+  if (positionals.length !== 1) {
+    return usage();
+  }
+
+  // non-null assertion safe because we already checked for length
+  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+  const inputFile = positionals.shift()!;
+  const inputFileExt = extname(inputFile);
+
   // non-null assertion safe because the outputType has a default
   // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-  if (!inputFile || !["json", "mermaid", "svg"].includes(values.type!)) {
-    usage();
-  } else {
-    const fileContent = readFileSync(resolve(process.cwd(), inputFile), { encoding: "utf8" });
+  if (
+    !values.type ||
+    !["json", "mermaid", "svg"].includes(values.type) ||
+    ![".md", ".td"].includes(inputFileExt)
+  ) {
+    process.exitCode = 1;
+    return usage();
+  }
+
+  const fileContent = readFileSync(resolve(process.cwd(), inputFile), {
+    encoding: "utf8",
+  });
+
+  if (inputFileExt === ".md") {
+    const markdownContent = await generateUpdatedMd(fileContent, values.type);
+    if (values.output) {
+      writeFileSync(resolve(process.cwd(), values.output), markdownContent);
+    } else {
+      console.log(markdownContent);
+    }
+  } else if (inputFileExt === ".td") {
     const parsedContent = parse(fileContent);
     if (values.type === "json") {
       if (values.output) {
@@ -50,6 +74,7 @@ async function main () {
       } else {
         console.log(JSON.stringify(parsedContent, null, 2));
       }
+
       return;
     }
 
@@ -60,6 +85,7 @@ async function main () {
       } else {
         console.log(mermaidContent);
       }
+
       return;
     }
 
@@ -71,11 +97,12 @@ async function main () {
         console.log(svgContent);
       }
     }
+
+    return;
   }
 }
 
-main()
-  .catch((err: Error) => {
-    process.exitCode = 1;
-    console.error(err.stack);
-  });
+main().catch((err: Error) => {
+  process.exitCode = 1;
+  console.error(err.stack);
+});
diff --git a/lib/index.ts b/lib/index.ts
index cb1608b..26a0f4e 100644
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -1,3 +1,4 @@
 export { parse } from "./parser";
 export { compileToMermaid } from "./compiler";
 export { renderMermaid } from "./renderer";
+export { generateUpdatedMd } from "./md-converter";
diff --git a/lib/md-converter.ts b/lib/md-converter.ts
new file mode 100644
index 0000000..a07ccc2
--- /dev/null
+++ b/lib/md-converter.ts
@@ -0,0 +1,78 @@
+import { parse } from "./parser/index";
+import { compileToMermaid } from "./compiler";
+import { renderMermaid } from "./renderer";
+
+const threatdownRegex = /```threatdown([\s\S]*?)```/g;
+
+const getMermaidSvg = async (mermaidFormatedData: string): Promise<string> => {
+  const testSvg = await renderMermaid(mermaidFormatedData);
+  return testSvg;
+};
+
+const cleanThreatdownBlocks = (input: string) => {
+  return input
+    .trim()
+    .replace(/^```threatdown/, "")
+    .replace(/```$/, "");
+};
+
+// Define an asynchronous function to process each match
+const processMatchAsync = async (
+  match: string,
+  mdEmbeddedType: string
+): Promise<string> => {
+  const cleanMatch = cleanThreatdownBlocks(match);
+  const jsonFormatedData = parse(cleanMatch);
+  const mermaidRaw = compileToMermaid(jsonFormatedData);
+  let mermaidSvg = "";
+  if (mdEmbeddedType === "svg") {
+    mermaidSvg = await getMermaidSvg(mermaidRaw);
+  }
+
+  return (
+    `<!-- ${match} --> \n` +
+    // Render Mermaid
+    `${
+      mdEmbeddedType === "json"
+        ? "```json\n" + JSON.stringify(jsonFormatedData) + "\n```\n"
+        : ""
+    }` +
+    // Render Mermaid
+    `${
+      mdEmbeddedType === "mermaid"
+        ? "```mermaid\n" + mermaidRaw + "\n```\n"
+        : ""
+    }` +
+    // Render SVG
+    `${mdEmbeddedType === "svg" ? "\n" + mermaidSvg + "\n" : ""}`
+  );
+};
+
+// generate the updated markdown file
+export const generateUpdatedMd = async (
+  file: string,
+  mdEmbeddedType: string
+): Promise<string> => {
+  try {
+    const threatdownMatches = file.match(threatdownRegex);
+
+    if (!threatdownMatches) {
+      throw new Error("No threatdown content found");
+    }
+
+    const newFilePromises = threatdownMatches.map((match) =>
+      processMatchAsync(match, mdEmbeddedType)
+    );
+    const newFileContentArray = await Promise.all(newFilePromises);
+
+    let newFile = file;
+    for (let i = 0; i < threatdownMatches.length; i++) {
+      newFile = newFile.replace(threatdownMatches[i], newFileContentArray[i]);
+    }
+
+    return newFile;
+  } catch (err) {
+    console.error(err);
+    throw err;
+  }
+};
diff --git a/test/fixtures/sample.md b/test/fixtures/sample.md
new file mode 100644
index 0000000..6065f6e
--- /dev/null
+++ b/test/fixtures/sample.md
@@ -0,0 +1,18 @@
+## This is a markdown document
+
+```threatdown
+__Attacker's goal__
+  - method which in order to be viable
+    + (high) requires this condition to be true
+    + and this condition which depends on either
+      - x to be true
+      - or y to be true
+    + hey this condition must be true too
+  - another method here too
+    - a condition which depends on assumptions
+      +? this might be a problem
+      +? but only if this happens
+        -? which assumes this also happens
+```
+
+### Above this is a graph