How can we help?
A real human reads every email. Most replies go out within one or two business days.
Email support
For bug reports, refund requests, or anything else.
We aim to respond within 1–2 business days.
Lost your license key?
Email support@hellomdx.com from the address you used to purchase. We'll resend your key.
Refunds
We offer a 14-day refund, no questions asked. Send us your order email and license key. See our Terms for details.
Bugs & feature requests
Found a bug or have an idea? Email support@hellomdx.com.
Frequently asked questions
Quick answers to the most common questions. Still stuck? Email us.
How much does MDX cost?
MDX is a $15 one-time payment. No subscription, no tiers, free updates. There is a 14-day free trial with no credit card required, and a 14-day no-questions-asked refund after purchase.
What operating systems does MDX support?
MDX runs natively on macOS (both Apple Silicon and Intel), Windows (.exe and .msi installers), and Linux (.AppImage, .deb, and .rpm packages).
Does MDX work offline?
Yes. The editor itself is fully offline — there is no MDX server in the loop. The only feature that requires internet is the optional AI ghost-writer, which calls the AI provider you choose directly using your own API key.
Where are my files stored?
Your files live on your own disk as plain .md markdown files. You can optionally sync them through your own iCloud Drive, Google Drive, Dropbox, OneDrive, or a local folder. MDX does not host your documents.
Which AI providers does the ghost-writer support?
MDX supports Anthropic Claude, OpenAI, Google Gemini, xAI Grok, and local models via Ollama or any OpenAI-compatible endpoint. You bring your own API key — your prompts go directly to the provider, never through MDX.
Does MDX support citations and bibliographies?
Yes. MDX has a built-in reference manager that imports BibTeX (.bib), RIS (.ris, .nbib, .enw), and CSL-JSON files. Citations are inserted via a sidebar picker using [@citekey] syntax. On export to DOCX, PDF, or HTML, citations are auto-numbered and a formatted References section is appended at the end of the document.
Can MDX edit Markdown files generated by ChatGPT, Claude or other AI tools?
Yes. MDX is designed for this workflow. It opens any .md file — including outputs from ChatGPT, Claude, Gemini, Perplexity, NotebookLM, Cursor, or any other tool that exports Markdown — and renders it as a document you can edit visually, then saves it back as plain .md. You can also set MDX as the default app for .md files on macOS, Windows, or Linux so double-clicking just works.
Does MDX require an account or send telemetry?
No. MDX does not require an account, does not send telemetry, and does not phone home. You buy the app, it opens, that is the entire flow.