Espruino Wifi - Dropped characters at runtime

...this seems to be a recurring issue... I'm sure you found this conversation about Espruino Serial Terminal drops characters., and you find more posts.

I suspect the issue is that Espruino is already working on some code while the upload is still going on. Therefore I always and strongly suggest not to do anything directly executing, such as .connect() and setInterval() in upload... sometimes even not require(). All the execution stuff goes into the onInit() or a function that is called from within onInit().

I don't know what board you are on, but sometimes processing resources get scarce.

Another option to speed-up your upload is to make modules out of pieces of your code and stick them into the modules folder in your sandbox folder - mified... (using google's online Web service, where you paste the module source code and you get back the minified code, which you stick into the same named file with .min.js suffix).

I hope this helps... I just recently made a similar app where an Espruino-Wifi is the sensor operating application, stepper motor controlling application, the Wifi Access Point, AND the http/s Web server... and it all works just perfect.