Extract outline API

Headings with level, slug, and line number.

POST /api/v1/extract/outline returns every heading in a markdown document with its level, text, slug id, and line number. The exact data structure you need to render a sidebar table of contents.

Overview

Pull the document's heading hierarchy (h1 through h6). Each item has a level, text, GitHub-style slug `id`, and 1-based line number. The slug ids match the anchors emitted by /api/v1/render.

Request

Authenticate with Authorization: Bearer YOUR_API_KEY and send a JSON body containing the parameters below. Pick your language:

curl -X POST 'https://trymarkdownviewer.com/api/v1/extract/outline' \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"markdown":"# Title\n\n## Section"}'

Body parameters

Field	Type	Required	Description
markdown	string	required	Markdown source.

Response

Success responses are wrapped in a data field. Errors use { error: { code, message } } with an appropriate HTTP status — see the error reference.

{
  "data": {
    "headings": [
      {
        "level": 1,
        "text": "Title",
        "id": "title",
        "line": 1
      },
      {
        "level": 2,
        "text": "Section",
        "id": "section",
        "line": 3
      }
    ],
    "count": 2
  }
}

Use cases

Sidebar TOC

Render a sticky right-rail TOC for a long-form article.

Doc indexing

Build a search index keyed by heading text and id.

Try in browser

Free tools that run the same logic locally — no API key, no upload.

Outline Reorder Mode
Drag-free section shuffle

Try it

Send a real request against your account in the API playground. Errors there link straight back to the error reference.