Create a table without a header in Markdown

Solution 1:

Most Markdown parsers don't support tables without headers. That means the separation line for headers is mandatory.

Parsers that do not support tables without headers

multimarkdown
Maruku: A popular implementation in Ruby
byword: "All tables must begin with one or more rows of headers"
PHP Markdown Extra "second line contains a mandatory separator line between the headers and the content"
RDiscount Uses PHP Markdown Extra syntax.
GitHub Flavoured Markdown
Parsedown: A parser in PHP (used e.g. in Laravel emails)

Parsers that do support tables without headers.

Kramdown: A parser in Ruby
Text::MultiMarkdown: Perl CPAN module.
MultiMarkdown: Windows application.
ParseDown Extra: A parser in PHP.
Pandoc: A document converter for the command line written in Haskell (supports header-less tables via its simple_tables and multiline_tables extensions)
Flexmark: A parser in Java.

CSS solution

If you're able to change the CSS of the HTML output you can however leverage the :empty pseudo class to hide an empty header and make it look like there is no header at all.

Solution 2:

If you don't mind wasting a line by leaving it empty, consider the following hack (it is a hack, and use this only if you don't like adding any additional plugins).

|   |   |
|---|---|
|__Bold Key__| Value1 |
| Normal Key | Value2 |

To view how the above one could look, copy the above and visit https://stackedit.io/app

It worked with GitLab/GitHub's Markdown implementations.

Solution 3:

Universal Solution

Many of the suggestions unfortunately do not work for all Markdown viewers/editors, for instance, the popular Markdown Viewer Chrome extension, but they do work with iA Writer.

What does seem to work across both of these popular programs (and might work for your particular application) is to use HTML comment blocks (''):

| <!-- -->    | <!-- -->    |
|-------------|-------------|
| Foo         | Bar         |

Like some of the earlier suggestions stated, this does add an empty header row in your Markdown viewer/editor. In iA Writer, it's aesthetically small enough that it doesn't get in my way too much.