Version of 8 August 2026 · Applies to /fx/api/*.json and /fx/widget.js
1. The service
The FX API republishes the weekly exchange rates that Japan Customs publishes for customs valuation. It is free, requires no key, and is provided by LoreaTec (loreatec.jp), the operator of this site.
2. Required link (the one real condition)
Every page, app screen or document that displays data obtained from this API must carry a visible, working link to https://loreatec.jp/e/ (or https://loreatec.jp/) — for example "FX data: free API by LoreaTec". The embeddable widget already includes this link: removing, hiding or obscuring it is a violation of these terms. Every JSON response repeats this condition in its link_required field. If you cannot place the link, do not use the API.
3. Rate limits
30 requests per minute and 500 requests per day per IP address. Above the limit the API returns HTTP 429 with a Retry-After header. The data changes at most once a week — cache it. If you legitimately need more, ask via the LoreaTec contact page.
4. Attribution of the underlying data
The rates themselves are public data from Japan Customs, reused under the Government of Japan Standard Terms of Use. If you republish the numbers, keep an attribution to Japan Customs as the source.
5. No warranty
The service is provided "as is", with no guarantee of availability, timeliness or accuracy. The legally effective rates are those publicly notified by each Director-General of Customs. Always confirm the applicable rate with your customs broker before filing a declaration. LoreaTec accepts no liability for decisions based on this API.
6. Fair use
Do not resell access to this API itself, present it as your own service, or use it in a way that degrades it for others. We may block abusive clients and may change or discontinue the service; material changes will be reflected on this page.