Not every request is idempotent and its not known when or why a request has failed. GETs are ok (in theory) but you can't retry a POST without risk of side effects.

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OptionOfT 2 hours ago | parent | next [-]

There were some issues with replaying certain GETs back in the day:

https://news.ycombinator.com/item?id=16964907

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bdangubic 3 hours ago | parent | prev [-]

I am a contractor and have been fixing shit large part of my career. non-idempotent POSTs are just about always at the top of the list of shit to fix immediately. To this day (30 years in) I do not understand how can someone design a system where POSTs are not idempotent… I mean I know why, the vast majority of people in our industry are just not good at what they do but still…

	▲	SoftTalker 3 hours ago \| parent [-]
		Yep. I worked in corporate back-office IT way before the web era. It was a requirement that every batch job be re-runable idempotently. So if it failed, you'd identify the bad data, excise it, rerun the job, and deal with the bad record in the morning.