Convert YAML to HTML Online

Paste a YAML table below, edit it if you need to, and get HTML back. The conversion runs in your browser, so nothing is uploaded, there is no size limit and there is no signup.

From

From a page

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Nothing here is uploaded. The parsing happens on this page.

Edit

Paste or upload something above and it will appear here.

ToDataMarkupDocumentsCodeSchemasImages

Header rowDetect numbersclassWrap in a div

The output will appear here once there is a table to convert.

What YAML is

YAML uses indentation instead of brackets. It is a superset of JSON, supports comments, and is meant to be edited by hand.

Kubernetes manifests, CI pipelines, Ansible playbooks and most modern config files.

What HTML is

An HTML table is a table element containing thead and tbody, with th cells for headers and td cells for data.

Web pages, email templates and anything pasted into a CMS.

What changes when you convert YAML to HTML

A YAML list of maps reads as rows and columns directly. Anchors and aliases are resolved before the table is built, so a repeated block arrives expanded rather than as a reference.

Semantic markup: a real thead, a real tbody, th for the header row. Angle brackets and ampersands in your data are escaped, so a value like <script> is written safely and shows as text on the page.

What carries over from YAML to HTML

YAML records 2 things about a table that HTML has no way to hold.

YAML distinguishes a number from the text of a number; HTML does not, so every value arrives as text and has to be re-parsed by whatever reads it next.

An empty cell and a missing one are the same thing in HTML, so a null and an empty string in the YAML both come out blank and can no longer be told apart.

HTML marks header cells differently from data cells, so the keys are lifted out and written once as a marked header row rather than repeated on every row.

The identifier 007 comes out of the HTML as 007. Reading it as a number would have made it 7, and an id that changes value is worse than one that stays text.

The role "Analyst, data" survives with its comma, in one cell rather than split across two. That is the first thing to check in any converted table, and the usual place a HTML file goes wrong.

The quotes around Jonah "Jo" Pryce are written as the HTML entity " in the HTML.

A worked example

Three rows of staff data, with an identifier that has a leading zero, a value containing a comma, a value containing quotes and one blank cell. Those are the four places formats disagree, so they are the four places to look.

YAML in

- id: "007"
  name: Halima Yusuf
  role: Analyst, data
  started: "2024-03-15"
  hours: "38.5"
- id: "012"
  name: Jonah "Jo" Pryce
  role: Engineer
  started: "2025-11-02"
  hours: ""
- id: "104"
  name: Wei Chen
  role: Manager
  started: "2023-06-30"
  hours: "40"

HTML out

<table>
  <thead>
    <tr>
      <th>id</th>
      <th>name</th>
      <th>role</th>
      <th>started</th>
      <th>hours</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>007</td>
      <td>Halima Yusuf</td>
      <td>Analyst, data</td>
      <td>2024-03-15</td>
      <td>38.5</td>
    </tr>
    <tr>
      <td>012</td>
      <td>Jonah &quot;Jo&quot; Pryce</td>
      <td>Engineer</td>
      <td>2025-11-02</td>
      <td></td>
    </tr>
    <tr>
      <td>104</td>
      <td>Wei Chen</td>
      <td>Manager</td>
      <td>2023-06-30</td>
      <td>40</td>
    </tr>
  </tbody>
</table>

Questions

How do I convert YAML to HTML?

Paste your YAML into the box above or drop the file onto it. Check the table in the grid, then copy or download the HTML from the output panel. It takes one step and the data never leaves your browser.

Why did my YAML value change meaning?

YAML reads several bare words as booleans. In the 1.1 spec that includes yes, no, on and off, which is why a country column containing NO for Norway can arrive as false. Quote values you want kept as text.

Will my numbers still be numbers?

They will read the same, but HTML stores them as text. Anything that sorts or sums the result will need to parse them first, and a leading zero or a currency symbol is the usual place that goes wrong.

Is there a limit on file size?

No. The work happens on your own machine, so the limit is your machine's memory rather than an upload cap. A file with tens of thousands of rows converts in a second or two.

Is my data uploaded anywhere?

No. The parsing and generating are done by JavaScript running on this page. You can watch the network tab while you convert and see that nothing is sent.