I don't think this modification is necessary to support it. Just set the value of BaseAPIMainURL or BaseWsMainURL before creating the client. Except in the options module where the associated values are not publicly available, if options support is also required, the associated values can be modified to be publicly visible. @eddieran

I modified it this way with reference to the current support for testnet's domain.

// UseTestnet switch all the API endpoints from production to the testnet
var UseTestnet = false

@eddieran Take a look at those comments.

Can anyone please approve the change on Test Network Websocket URLs? The old domains are no longer supported, and I am receiving 'websocket: bad handshake' error when calling the binance.WsAllMiniMarketsStatServe function which the client does not provide, thanks to this bug.

@JimBeam2019 — this PR adds binance.us (US domain) support, not Testnet WebSocket fixes. The diff doesn't touch testnet.binance.vision URLs. Your testnet handshake error is a separate issue and worth filing on its own — happy to look at it if you open a new ticket with the failing call signature.

@xyq-c-cpp — sorry for the long silence. Re-reading your earlier comment, I agree the public-variable approach is cleaner. The PR currently exposes a flag rather than rewriting endpoints, which I think keeps it minimal: binance.UseUSDomain = true is parallel to the existing binance.UseTestnet = true pattern, so users don't need to know which constants to overwrite. If you'd still prefer I drop the flag and just document that users should set BaseAPIMainURL directly, I can rework it that way.