A release-note table
| Change | Status | | --- | --- | | New API | - [x] Ready |
Produces semantic table and task-list markup from the GFM source, rather than a string of hand-written replacement rules.
📑Markdown to HTMLReady
820 / 200,000 source characters·95 rendered words·27 lines·~1 min read
Review hints
- 1 remote image reference is retained in the HTML output but deliberately not loaded in this preview.
What “safe HTML” means here
This is a Markdown-to-HTML workbench, not a sanitizer for arbitrary HTML. Raw HTML is intentionally omitted rather than cleaned and re-emitted. Generated links keep HTTP(S), mailto:, tel:, or relative destinations; generated images keep HTTP(S) or relative sources. External image URLs stay in the downloaded/copied HTML but are replaced by a text placeholder in this preview so simply opening the tool does not request them.
Capability checkedVerified September 9, 2026
What works
- Parse CommonMark with GFM tables, task lists, strikethrough, autolinks, footnotes, and fenced code blocks
- Omit raw HTML and remove unsafe link or image URL schemes before the preview or HTML fragment is produced
- Withhold every image source from the preview while retaining eligible image URLs in the exported fragment
Important limits
- This is a Markdown-to-HTML converter, not a general-purpose HTML sanitizer; raw HTML is deliberately dropped instead of being cleaned and re-emitted
- Previewed links open only when a visitor clicks them, and previewed image URLs are never requested; copied or downloaded HTML can load eligible external images when placed on another page
What the Markdown to HTML does—and does not do
Exact supported inputs, outputs, limits, and primary sources for the current implementation.
Accepted input
- Pasted CommonMark or GitHub Flavored Markdown source up to 200,000 source characters
- A locally opened .md, .markdown, or plain-text file up to 1 MiB when its decoded source is within the 200,000-character converter limit
- Markdown links and images with safe HTTP(S), mailto:, tel:, or relative destinations as appropriate to the element
Produced output
- An unstyled HTML fragment generated from CommonMark plus GFM constructs
- A safe browser preview from the same element and attribute allowlist as the HTML output
- Copyable or downloadable HTML plus generated heading IDs, an outline, document stats, and focused review hints
Operational limits
- Source input is limited to 200,000 characters; local files also have a 1 MiB read limit and are rejected before opening when decoded source exceeds that converter limit
- The output is an unstyled HTML fragment, not a complete HTML document or an email template
- MDX or JSX, front matter, Mermaid, mathematics rendering, syntax highlighting, raw HTML, and an input-encoding picker are not supported
Known limitations
- This is a Markdown-to-HTML converter, not a general-purpose HTML sanitizer; raw HTML is deliberately dropped instead of being cleaned and re-emitted
- Previewed links open only when a visitor clicks them, and previewed image URLs are never requested; copied or downloaded HTML can load eligible external images when placed on another page
- The heading and image checks are focused authoring hints, not a full accessibility, security, or publishing-policy audit
Standards and primary sources
Capability claims last reviewed September 9, 2026. Review dates describe the implementation audit, not content freshness by itself.
Use the Markdown to HTML with the right expectations
Most Markdown-to-HTML pages make the preview and copied markup follow different paths, quietly allow raw HTML, or load every image URL pasted into the editor. This workbench creates both views from one constrained document model: Markdown and GFM are supported, raw HTML is omitted, unsafe URL schemes are removed, and image sources are retained for export without being requested during preview. The outline and checks help an author catch a skipped heading or missing image text alternative before publishing.
When it is the right tool
- Turning a README, knowledge-base draft, or CMS fragment into semantic HTML
- Reviewing GFM tables, task lists, footnotes, code blocks, and links before copying markup
- Inspecting a document outline and generated heading IDs before publishing a standalone page
- Converting a local Markdown file without the preview requesting its remote image URLs
A deliberate choice
Tooleras keeps this page specific to the job above instead of claiming support for adjacent formats, platforms, or edge cases it cannot verify. Open the capability guide for the exact inputs, outputs, limits, and sources.
Checked examples
An external image reference
Keeps the eligible image source and alt text in copied HTML, while the local preview uses a visible placeholder and makes no image request.
Unsafe pasted markup
<script>alert(1)</script> [bad](javascript:alert(1))
Drops the raw HTML, removes the unsafe destination, and explains the safety decision instead of claiming arbitrary HTML was sanitized.
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