diff --git a/dev/build.js b/dev/build.js
index 25befb35..b80abf62 100644
--- a/dev/build.js
+++ b/dev/build.js
@@ -4,25 +4,34 @@ import { parse, join } from 'path'
 import * as esbuild from 'esbuild'
 
 import { rootDir, DEV, time } from './utils.js'
+import { generateContentJSON } from './exo-parser.js'
 
-const getHash = async head => {
+const getHash = async (head) => {
   if (!head.startsWith('ref:')) return { hash: head.trim(), branch: 'detached' }
   const parts = head.split(' ')[1].trim().split('/')
   const branch = parts[parts.length - 1]
   const hash = await readFile(join(rootDir, '.git', ...parts), 'utf8')
   return { hash: hash.trim(), branch }
 }
-  
+
 try {
   const head = await readFile(join(rootDir, '.git/HEAD'), 'utf8')
   const { hash, branch } = await getHash(head)
   process.env.HASH = `${branch}@${hash.trim()}`
 } catch (err) {
-  console.warn('Unable to load git commit version, fallback to time based hash', err)
+  console.warn(
+    'Unable to load git commit version, fallback to time based hash',
+    err,
+  )
   const now = Math.floor((Date.now() - 16e11) / 1000)
   process.env.HASH = `unk@${now.toString(36)}`
 }
 
+export const exoJsDir = () => readdir(join(rootDir, 'js-introduction'))
+
+export const bundleJSONDir = (dirName) =>
+  mkdir(join(rootDir, dirName), { recursive: true })
+
 const templateDir = join(rootDir, 'template')
 const readEntry = async ({ name, ext, base }) => [
   name,
@@ -51,6 +60,7 @@ const config = {
 
 const serve = () => esbuild.serve({ servedir }, config)
 const generate = async (file = 'index') => {
+  await generateContentJSON('js-introduction', 'public')
   const content = await readdir(templateDir)
   const entries = await Promise.all(content.map(parse).map(readEntry))
   const templates = Object.fromEntries(entries)
@@ -61,7 +71,6 @@ const generate = async (file = 'index') => {
     (cache[key] =
       templates[key]?.replace(/<!-- ([a-zA-Z0-9]+) -->/gm, replace) ||
       `<!-- missing template ${key} -->`)
-
   return readTemplate(file)
 }
 
diff --git a/dev/exo-parser.js b/dev/exo-parser.js
new file mode 100644
index 00000000..5d126146
--- /dev/null
+++ b/dev/exo-parser.js
@@ -0,0 +1,81 @@
+import { readdir, writeFile, readFile, mkdir } from 'fs/promises'
+import { join, parse as pathParse } from 'path'
+
+import { fromMarkdown } from 'mdast-util-from-markdown'
+
+import { rootDir } from './utils.js'
+
+// returns a flatten array of all the children
+const children = (n) =>
+  n.children ? [n, ...n.children.flatMap(children)] : [n]
+
+const getTrimValue = (n) => n.value?.trim()
+const textContent = (n) =>
+  children(n).map(getTrimValue).filter(Boolean).join(' ') || ''
+
+const isH1 = (node) => node.type === 'heading' && node.depth === 1
+const isH2 = (node) => node.type === 'heading' && node.depth === 2
+const isH3 = (node) => node.type === 'heading' && node.depth === 3
+const isP = (node) => node.type === 'paragraph' || node.type === 'text'
+const isCODE = (node) => node.type === 'code' || node.type === 'inlineCode'
+const isLI = (node) => node.type === 'list'
+
+const parseContent = (nodeList) => {
+  const content = { description: '' }
+  let mode,
+    test = isP
+  for (const node of nodeList) {
+    if (!content.title && isH1(node)) {
+      content.title = textContent(node)
+    } else if (isH2(node)) {
+      mode = textContent(node).toLowerCase()
+      content[mode] = []
+    } else if (mode === 'notions') {
+      if (isLI(node)) {
+        content.notions = children(node).map(getTrimValue).filter(Boolean)
+      }
+    } else if (mode === 'instructions') {
+      if (isP(node) || isLI(node)) {
+        content.instructions = children(node)
+          .map(getTrimValue)
+          .filter(Boolean)
+          .join(' ')
+      }
+    } else if (mode === 'tests') {
+      if (isH3(node)) {
+        test = { name: textContent(node) }
+        content.tests.push(test)
+      } else if (test && isCODE(node)) {
+        test.code = textContent(node)
+        test.lang = node.lang
+      } else {
+        console.warn('ignored node', node)
+      }
+    } else if (mode) {
+      // any other mode is stored in raw tree
+      content[mode].push(node)
+    } else {
+      // before any mode is set, we are writing the description
+      content.description += `${textContent(node).trim()}\n`
+    }
+  }
+  return content
+}
+
+const readdirParse = async (path) =>
+  (await readdir(join(path))).map((file) => pathParse(join(path, file)))
+
+export const generateContentJSON = async (input, ouput) => {
+  const dirList = await readdirParse(join(rootDir, input))
+  const contentProcessing = dirList.map(async ({ dir, base, name }) => {
+    const content = await readFile(join(dir, base))
+    const root = fromMarkdown(content)
+    const parsed = parseContent(root.children)
+    const outDir = join(rootDir, ouput, dir.slice(rootDir.length))
+    await mkdir(outDir, { recursive: true })
+    await writeFile(join(outDir, `${name}.json`), JSON.stringify(parsed))
+    return [name, parsed]
+  })
+
+  return Object.fromEntries(await Promise.all(contentProcessing))
+}
diff --git a/dev/server.js b/dev/server.js
index 0f1d5bb5..df9a4bbd 100644
--- a/dev/server.js
+++ b/dev/server.js
@@ -53,4 +53,6 @@ createServer(async (req, res) => {
 
   // Apply headers from the worker
   sendResponse({ body, options, res })
-}).listen(PORT, () => console.log(`Dev server ready on ${process.env.DOMAIN}`))
+}).listen(PORT, () => {
+  console.log(`Dev server ready on ${process.env.DOMAIN}`)
+})
diff --git a/package.json b/package.json
index 703b4077..15b3c6c8 100644
--- a/package.json
+++ b/package.json
@@ -12,6 +12,7 @@
   "dependencies": {
     "esbuild": "^0.11.2",
     "fast-toml": "^0.5.4",
+    "mdast-util-from-markdown": "^1.0.4",
     "preact": "^10.5.13"
   }
 }