How do software developers outside of Japan collect and remit Japanese Consumption Tax?

Disclaimer: I am not a financial advisor or an official tax advisor. You should consult your agent to discuss and plan a real set of actionable steps that allow you to comply with the regulation.

According to Japan Consumption Tax Law (JCT), software developers outside japan are responsible for collecting and remitting JCT. How can they do that?

When entering a regional market, one must always comply with the regulatory body that is in place there. In your case for Japan, you must pay taxes if you sell in the Japanese market.

One approach to keeping track on how much you need to pay the Japanese government is by keeping track of all sales in Japan and the revenue stream.

From that, you can calculate how much you need to remit to the government.

Japanese Tax Document: You can pull up the rates here.

as no US states are mentioned in the article: does this mean developers must remit tax in those states?

Underneath the section for United States, you can find that Google has already listed the regulatory states that have sales tax, and they will remit the tax for you.

Excerpt from Google's Documentation:

In accordance with sales tax requirements, Google is responsible for determining, charging, and remitting sales tax for Google Play Store app and in-app purchases by customers in these states. Google will collect and remit sales tax to the appropriate tax authority, as applicable.