About buying the paid apps (MrkEditor, MrkDown, MrkDiff Hex). The free apps (MrEditor, MRDown, MrDiff, …) are not sold.
| Sales and payment | The paid apps are sold, and payment is handled, by Polar (polar.sh) as the reseller. Orders, receipts (invoices), tax and refunds go through Polar. |
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| Development and support | TABATA Hitoshi (田畑 ひとし) develops and supports the software. Questions: support@mrktools.app (Contact) |
| Price | One-time purchase, in US dollars.
The total you pay is shown at checkout. If you live in Japan, no tax is added on top of the displayed price (as of October 2026). |
| Payment | By the methods shown at checkout (Polar), when you order. |
| Delivery | Right after payment: a license key is issued and the app can be downloaded from the buyers' page. |
| Refunds | Because this is a download, we don't refund for personal reasons. If the software does not work as described on its product page, email us within 30 days of the purchase and we will refund it. This covers MrkEditor, MrkDown and MrkDiff Hex. MrkDiff Hex can be tried with every feature, free, for 14 days before you buy. The refund is paid back through the payment service (Polar), and the license ends. Because this is a download, there is nothing to send back and no shipping cost. |
| If it doesn't work | Please email support@mrktools.app first. |
| System requirements |
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| License scope | One license can be activated on up to 2 Macs. |
| Recurring charges | None. It is a one-time purchase. |
Last updated: October 12, 2026