Malaysia Central Bank Open Data.
Bank Negara Malaysia Open Data API is a free Government API that requires no API key, is served over HTTPS and has unconfirmed CORS support.
Details from apikijangportal.bnm.gov.my.

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The Bank Negara Malaysia Open Data API is provided by BNM (apikijangportal.bnm.gov.my).
Yes. The Bank Negara Malaysia Open Data API is listed in the Government category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The Bank Negara Malaysia Open Data API requires no authentication, so you can start making requests without signing up.
CORS support for the Bank Negara Malaysia Open Data API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Bank Negara Malaysia Open Data API is served over HTTPS, so it's safe to use in production.