Qiita / Zenn Compatibility Checker
Qiita and Zenn are Japanese developer publishing platforms, and their Markdown dialects differ. Paste an article to see what would break after publishing. Differences with a one-to-one mapping are converted; the output is a draft.
Paste the article Markdown here. Include the frontmatter and the title and tags get checked too.
What this does and does not do
- Detection covers the 74 catalogued differences: 37 convert automatically, 14 need a decision, and 23 have no equivalent on the other side.
- Zenn does not render raw HTML. The details element, width attributes on img, and dl definition lists that Qiita articles rely on show up as literal tag text on Zenn instead of raising an error.
- 21 differences produce neither an error nor a warning. That kind is only visible once published, so treat previewing as part of the process.
- The Qiita renderer was never executed here. Every claim about how something finally looks on Qiita comes from official documentation and from reading the implementation.
- Only body text and frontmatter are handled. Image files are not moved or uploaded, and what you paste never leaves your browser.
About the differences between Qiita and Zenn
This tool diagnoses first and converts second
Qiita and Zenn are the two large Japanese developer publishing platforms, and both take Markdown with their own extensions. There are 74 catalogued differences between them. 37 have a one-to-one mapping and can be converted mechanically. The remaining 51 split into 14 where a human has to pick a target and 23 that simply have no counterpart. Conversion is applied to those 37 only; everything else is reported with the options laid out.
Zenn does not render raw HTML
Zenn's renderer runs markdown-it with its default settings, which leaves raw HTML disabled. A collapsible details block, an img with a width attribute, or a dl definition list therefore does not fail on Zenn: the tag text itself becomes visible to readers. The build passes, nothing warns you, and the damage shows up only after the article is live. 21 differences behave this way.
Qiita note and Zenn message are not one-to-one
Qiita's note block has three levels, info, warn and alert. Zenn's message block has two, the default and alert. Writing :::message warn does not produce a block at all; the literal string appears in the body. This tool asks which of the two Zenn levels a warn block should map to rather than deciding for you.
Zenn to Qiita is the structurally safer direction
Qiita passes raw HTML through, so Zenn-specific syntax can be carried over as HTML. What gets dropped is frontmatter that only exists on the Zenn side, such as the eyecatch emoji and the publication timestamp, and Qiita does not use those fields. Accidents are less likely than in the other direction, but the Qiita renderer was not executed here, so the same review still applies.
Review before you publish
A Zenn slug is unique across the whole site and cannot be changed once created. The publication date is likewise fixed after it is set. Publishing the wrong thing cannot be undone, so treat the output as a draft and look at the preview first.