Interestingly, even blogs and media outlets in Japan that introduce well-known overseas FX brokers claim they are safe because they are STP, have high execution rates because they are ECN, are highly transparent, or are DMA and NDD...

I think there are very few overseas FX brokers where you can actually verify which order matched with which LP's order.
Most brokers stick to non-last look.
I wonder, what exactly is the role of overseas FX brokers supposed to guarantee?
Is it to pass orders to LPs?
Or to process orders lined up in the BOOK as B? (Although it’s possible with A too)
I feel like the terms A-book and B-book hide the true meaning of the processing behind them.
But most brokers have their servers and data centers separate, with the data center located in a branch of the world's top company, where LA is performed.
That’s mostly how it is.
I’m not saying LA is bad, but creating smaller pools within a huge pool limits the execution, and while feeds might become faster, accuracy diminishes.
I learned around 2019 that they are housed in data centers performing DMA.
Since then, I became interested in various systems.
There are companies in Japan that do A-book trading.
If you claim that processing orders from Japan that take 250ms to return in non-last look is the fastest, that’s a lie.
Even if you place a server in Tokyo and have a data center in New York, order responses come in within 148ms.
Japanese securities companies mostly use B-book, and even if they claim to use A-book... in reality, processing speed is as slow as making two round trips between Tokyo and London.