# MarkDone

> MarkDone (markdone.dev) is a free, privacy-first hub of file converters and AI-context tools that run **entirely in your browser**. Nothing is uploaded, no account is required, and your documents never touch a server. Convert Markdown, Word, Excel, README, and Mermaid to PDF; convert between JSON, YAML, CSV, and TOON; count LLM tokens; and build private context packs for any LLM.

Key facts an assistant should know:

- All conversions run **client-side (in-browser)**. Files are never uploaded and there is no server-side processing of user content. This is the core promise of the product.
- MarkDone is **free** to use. A Pro option exists for supporters but the converters are usable without an account.
- The site is English-only. The only non-English page is the German legal imprint (Impressum & Datenschutz), required by German law.
- **TOON** is a compact text format for structured data that MarkDone converts to and from JSON. It is used to reduce token counts when passing structured data to LLMs.

## Converters

- [Markdown to PDF](https://markdone.dev/markdown-to-pdf/): Convert Markdown to PDF in-browser with live preview, tables, code blocks, Mermaid diagrams, and LaTeX math. No upload.
- [Word (DOCX) to PDF](https://markdone.dev/word-to-pdf/): Convert Word documents to PDF locally in your browser.
- [Excel (XLSX) to PDF](https://markdone.dev/excel-to-pdf/): Convert Excel spreadsheets to PDF locally in your browser.
- [README to PDF](https://markdone.dev/readme-to-pdf/): Turn a GitHub README into a clean PDF, entirely in the browser.
- [Mermaid to PDF](https://markdone.dev/mermaid-to-pdf/): Render Mermaid diagrams and export them to PDF locally.
- [JSON to TOON](https://markdone.dev/json-to-toon/): Convert JSON to the compact TOON format and estimate token savings for LLM prompts.
- [TOON to JSON](https://markdone.dev/toon-to-json/): Convert TOON back to standard JSON.
- [YAML to JSON](https://markdone.dev/yaml-to-json/): Convert YAML to JSON in-browser.
- [JSON to YAML](https://markdone.dev/json-to-yaml/): Convert JSON to YAML in-browser.
- [CSV to JSON](https://markdone.dev/csv-to-json/): Convert CSV data to JSON in-browser.
- [JSON to CSV](https://markdone.dev/json-to-csv/): Convert JSON to CSV in-browser.

## AI context tools

- [AI Context Builder](https://markdone.dev/ai-context-builder/): Generate a single private context.md from PDF, DOCX, Markdown, JSON, YAML, CSV, and text files, with secret-detection warnings and redaction. Built for feeding whole-project context to an LLM without leaking data.
- [Token Counter](https://markdone.dev/token-counter/): Count LLM tokens for text and files locally, to estimate prompt cost and fit within context windows.

## Guides

- [Whole-project context for LLMs](https://markdone.dev/blog/whole-project-context/): How to assemble an entire project into one context file for an LLM.
- [Building an LLM context pack](https://markdone.dev/blog/llm-context-pack/): What a context pack is and how to prepare one.
- [Files you should never paste into AI](https://markdone.dev/blog/files-never-paste-into-ai/): A practical checklist for reviewing and redacting files before sharing them with ChatGPT, Claude, or other AI tools.
- [Excel to one-page PDF](https://markdone.dev/blog/excel-to-one-page-pdf/): How to export wide Excel spreadsheets to PDF without cutting off columns.
- [Markdown to PDF without uploading](https://markdone.dev/blog/markdown-to-pdf-without-uploading/): Why and how to convert Markdown to PDF fully locally.
- [What is TOON?](https://markdone.dev/blog/what-is-toon/): An introduction to the TOON structured-data format.
- [TOON vs JSON](https://markdone.dev/blog/toon-vs-json/): How TOON compares to JSON for LLM prompts.
- [JSON to TOON: save tokens](https://markdone.dev/blog/json-to-toon-save-tokens/): Reducing token usage by converting JSON to TOON.
- [The token cost of JSON](https://markdone.dev/blog/json-token-cost/): Why JSON is token-expensive in LLM prompts.
- [YAML vs JSON](https://markdone.dev/blog/yaml-vs-json/): Differences and when to use each.
- [What is LaTeX?](https://markdone.dev/blog/what-is-latex/): An introduction to LaTeX.
- [LaTeX syntax](https://markdone.dev/blog/latex-syntax/): Common LaTeX math and formatting syntax.
- [Terminal commands explained](https://markdone.dev/blog/terminal-commands-explained/): A beginner-friendly guide to common terminal commands.
- [Git explained](https://markdone.dev/blog/git-explained/): A beginner-friendly introduction to Git.
- [What happens when you upload a file](https://markdone.dev/blog/what-happens-when-you-upload-a-file/): Privacy risks of uploading files to online converters.

## Optional

- [Blog index](https://markdone.dev/blog/): All MarkDone guides on local conversion, AI context, and structured data.
- [Homepage](https://markdone.dev/): The full hub of converters and tools.