Standard Markdown
Headings, lists, emphasis, code fences, tables and task lists (GFM). Raw HTML and unsafe links are stripped before anything renders.
Free — no sign-up
Markdown that reads
like a document
Four small tools for the file you already have: a reader for long documents, a viewer for assistant answers, inline Mermaid diagrams, and a README opened straight from its URL. Everything runs in the browser.
01 · Tools
Start from the file, not from a menu.
Each page opens with the tool at the top and a sample already loaded. Pick the one that matches what you are holding.
Markdown Reader A long document you can actually finish Outline built from the headings, reading progress, focus mode and four ways to lay out the same file. Made for manuals and specifications, not for a two-line note.
Open tool
AI Markdown Viewer Assistant answers, without the asterisks Paste what ChatGPT or Claude gave you — or open the .md it let you download — and get headings, tables and code blocks where they belong.
Open tool
Markdown + Mermaid The diagram stays code Flowchart, sequence and ER diagrams drawn at the exact point they appear in the text. Nothing to export, nothing to keep in sync.
Open tool
Markdown from URL Read a README before you clone Paste the address of any public .md file — the GitHub file page counts — and read it formatted instead of scrolling raw syntax.
Open tool
02 · Nothing to configure
Working on the first click. No install.
Every feature below is on by default. A modern browser with JavaScript enabled is the whole requirement.
Mermaid diagrams
Flowchart, sequence and entity-relationship blocks render inline. No plugin, no export step, no second tool.
Syntax highlighting
Code blocks highlighted for the usual languages — JavaScript, Python, SQL and the rest — so a snippet reads like a snippet.
Outline and progress
A table of contents built from the H2 and H3 headings, with the section you are in marked as you scroll.
Study cards and notes
Turn a section into a card and write a note beside it, so the annotation stays attached to the part of the text it answers.
Slides from the same file
Headings become slides for a presentation. One document, no duplicated deck drifting out of date.
FAQ
What is worth knowing before you paste.
Short answers to what people ask on the first visit.
Is my document uploaded anywhere?
No. Parsing and rendering happen in your browser, on your device. The file is never transmitted to a server of ours, which is also why it keeps working with the network off.
Do I need an account?
No account, no email, no usage limit. Open a page and the tool is already running, with a sample document loaded.
Which files can it open?
Markdown files (.md, .markdown), plain text (.txt) and Gherkin feature files (.feature). You can also paste the text directly, or point the reader at the URL of a public file.
Why is the rest of the site in Portuguese?
Sanctuary Reader started in Brazilian Portuguese. This home page and the four tool pages are what exists in English so far, so the guides, the Markdown reference and the blog are kept out of the English menu rather than shown behind a translated label.
How large a document can it handle?
Documents up to a few megabytes open comfortably. Past that the browser, not the tool, becomes the limit — split the file, or open only the section you are reviewing.
Open the file you have been scrolling raw.
Paste the text, choose a file or hand over a URL. No sign-up, no install, processed on your device.