Drop your .md draft onto the viewer and it renders the way readers will see it — headings, tables, code blocks, task lists — within about three seconds, right in your browser. Rendering happens locally on your device, so nothing is uploaded and the preview keeps working even with the network switched off after first load.
Open the viewer — drag in your .md file →Most previewers render only the basics: plain headings convert fine, but GitHub-flavoured features — task lists, footnotes, tables with column alignment, fenced code with syntax highlighting — break silently, and you find out after pushing. This preview renders the full CommonMark + GFM feature set client-side, so a README draft or documentation post looks like the published page while still being a private working copy. Practical checks before publishing: table-of-contents anchor links jump to the right sections, wide compatibility tables stay inside the layout instead of spilling off-screen, and long documents scroll without lag. A 10 MB draft renders at the same speed as a short one because there is no upload round-trip, and the app shell is cached after the first visit, so you can finish previewing on a plane. When it looks right, export the rendered HTML or copy the source and publish.
.md / README.md file onto the drop zone (or click to browse).