Easy, professional, and ready to use.
Kantan Seikyu is an all-in-one invoicing app that anyone can use to create beautiful business documents with ease.
Whether you’re a freelancer, small business owner, or side-business operator, you can create professional invoices, quotations, receipts, purchase orders, and delivery notes within minutes — no registration required.
Key Features
Create and manage quotations, invoices, receipts, purchase orders, and delivery notes.
Multi-language and multi-currency support for international business.
Fully compliant with Japan’s Qualified Invoice System (Invoice制度) and Electronic Bookkeeping Law.
NEW: Invoice report – instantly view statistics and export data.
NEW: Custom email templates for smooth client communication.
NEW: Keyboard shortcuts for faster desktop operations.
Manage multiple bank accounts and optimize transfer fees (supports international transfers).
Sync data securely via cloud drive or work fully offline.
No account or sign-up required — start using it immediately.
Ideal For
Freelancers and self-employed professionals.
Small businesses, startups, and international traders.
Users who need invoice compliance (Invoice制度対応).
Those managing side businesses (副業).
Entrepreneurs who value simplicity, privacy, and speed.
Ratings & Reviews
This app has not received enough ratings or reviews to display an overview.
■ New: AI Link (desktop only)
・AI apps such as Claude Desktop can now read your EasySeikyu documents, clients and items. Ask for revenue summaries or a list of overdue invoices in plain conversation.
・Any data change proposed by AI goes into an approval queue. Nothing in your data changes until you review and approve it in the app.
・AI can also draft emails such as payment reminders. It never sends them — review the draft and send it yourself from your own mail app.
・All communication stays on this computer. Your billing data is never sent anywhere.
・Turn it on from Settings > AI Link.
■ Improvements
・Date fields can now be typed directly. Formats like 2026/8/13 and 20260813 are accepted, and unrecognised dates are flagged immediately.
・Closing a document now asks "Keep editing / Discard / Save". You are now warned even if you only entered a number, date, subject or note.
・New items now take the standard tax rate of your configured country. Reordering the item list no longer changes the default.
・You can now select several items at once and add them all to a document.
・On desktop, adding line items now uses a floating panel. Add items one after another while watching the document, and drag them to any position.
・Reworked the first-run setup screens.
■ Fixes
・Fixed the loading spinner never stopping when PDF generation failed.
・Fixed image files being left behind when deleting several items at once.
Version 1.13.1
The developer, 瑜 邹, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Privacy practices may vary based, for example, on the features you use or your age. Learn More
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
