•  filling of standard B2C and B2C invoices
  • Automatic tax calculation
  • Reverse calculation of pre-tax price
  • Catalogue of often used product/service names (supports user defined items)
  • Zoom for the Chinese Numerals used on the invoices
  • Export/sharing as image
  • Export as CSV file (added in version 1.1)
  • saving invoices locally on device for archiving and sharing
  • Language supported: English, Chinese Traditional, Polish

This software uses Kastri by DelphiWorlds – see  their license HERE. Kastri is under MIT license, and it is a cross-platform library which builds upon the existing RTL, FMX and VCL libraries in Delphi, supports a number of newer APIs that you won’t find in FMX/RTL, and “backfills” for missing APIs.


Add up to 5 sale items to your invoice (either b@C or B2B) with a custom name, price and quantity for each item. Save the edited invoice locally for archiving. You can then always browse locally archived invoices, look up one that you want to review, or share.

Although the shareable invoices generated by this app cannot be used in lieu of original invoices, but it is a great way for managing electronic copies for keeping or sharing out to your customers. For example, if you sell your products online, you might share the electronic copy of the invoice to your buyer immediately, and later supply the original one shipped with your product by a courier.


The app comes with a small catalogue of some products and services common for small businesses. Furthermore you can add your own items to this catalogue. This is a simple feature, but it adds a great value to business owners, especially foreign entrepreneurs in Taiwan, because:
You can choose items instead of typing them in – if you have any products or services that you repeatedly sell, just add them once, and then pick them from a menu for faster generation of sale records
You can manage translations – Taiwan accountants generally expect entries on the invoices in Chinese. The app allows you to enlist your sale items in your own language in the catalogue along with a Chinese translation that gets used on the actual invoice. Also, in Chinese there are many different words used to count nouns (so called 量詞). It might be overwhelming to keep a track of what measure words to use with which sale items. Catalogue allows you to define this one time, and then just use it


A valid Taiwan business invoice, among other things, must contain a grand total price for the entire sale transaction transcribed using  special Chinese Numerals. These are not the same as common numerals used in Chinese language, and most people either never uses them, or only uses them uniquely for writing down sale/purchase/rent figures on invoices and other legal contracts. These numerals are quite complex in terms of number of strokes used, and are not often used which makes them, well, not easy to learn. Even native Chinese speakers seldomly remember how to write them by hand. INVOICER will automatically convert grant total price into these numerals for you, print them onto the electronic copy of the invoice, and also show you an enlarged characters for easing you in copying them over to the actual invoice. In fact, you can even use INVOICER solely as a fast tool for converting numbers into these numerals, if you ever need it.


If you are going to issue a B2B (business to business) invoice, so called 三聯式發票 in Chinese, you will need to fill in the Tax Id number and the Business Name of the buyer. The Business Id numbers in Taiwan consist of 8 digits. If you type a properly formatted Tax Id into the corresponding field in INVOICER app, a request will be automatically sent to Department of Commerce, MOEA, Commerce Industrial Services Portal at in an attempt to find the registered business name matching the tax id number. If the automatic lookup succeeds, the returned business name of the buyer will automatically be filled for you. In fact, you might even use INVOICER when you only need to look up a company name which you know a tax number of. As reported by some users, the API calls used for this feature sometimes don’t seem to work when using cellular Internet (due to a connection timeout) but work well over WiFi connection. These reported issues are difficult to reproduce, however, and if you encounter an inconsistency in the responsiveness of this feature, it might be due to issues regarding the quality of service on the side of the API provider.


As a foreign owned startup Perun Inc.feels relatable and sympathetic towards all local foreign (co-)owned startups in Taiwan. INVOICER is a token of support, in hope of actually helping fellow entrepreneur community in handling some aspects of business operations, no matter how small or basic.
Hopefully it will turn out of use to you out there. At the very least, it aims at being the best in its class. Both Google Play Store and Apple AppStore have multiple app listings aimed at the same general problem. A diligent research into them, however, made us convinced than no other “similar” app can match the level of features choice and UI of INVOICER.

If you find yourself wishing there was a feature present which is currently lacking, please do let us know, by sharing a feature request with us at: or directly at the Play/Appstore listing.

Our iOS version is already working on iPhones, however, we are still awaiting Apple’s successful review of our app submission to the AppStore. It has been rejected multiple times due to unidentified problems with “metadata” which have to do not with the app itself, but the text/image description of the listing. We are working on overcoming this, so please stay tuned.

As we plan to gradually grow INVOICER into more and more features, we plan, at some point, to add in-app purchase opt-in premium features. Doing it will allow us to fund more resources to be committed to this app. It will also allow you to show some support back to us. We already have an extensive backlog of things that can be implemented, and sky is the limit, really. But with a scale, the project will become costly for us in terms of time and resources. But that’d generally be a nice problem to have, so we’re looking forward to it!