200 Milliseconds: The Hidden Life of a Single HTTP Request
An interactive visualization follows one HTTP request from a coffee-shop click to order confirmation in 211.4 milliseconds, revealing seven stops, six cross-country trips, and forty machines. It breaks down the journey: touchpad interrupts, browser hit testing, cache misses, TCP/TLS handshakes, and the server side—all while a live clock tracks the elapsed time. The piece highlights how caching and warm sockets make repeat requests dramatically faster, and why POST requests bypass caches entirely.
By the time the confirmation renders, the request and its replies will have crossed North America six times and passed through around forty machines, running a hundred million lines of other people's code.
- Retr0id
> Violet marks the data as it moves, always top to bottom. Nothing else on the page uses that color.
I'm seeing 3 violet elements on my screen. "ms" in the top left, the dot next to that text, and a dot on a horizontal timeline at the lower edge of the screen. Scrolling down I see yet more violet UI elements, I assume the one on the vertical timeline represents the data, while all the others represent... other things.
It seems violet is just the accent colour used for everything, which makes it an especially perplexing comment. I can only assume the "author" never even read the LLM's output before posting it.
- paimapi
is it bad that while this does look like a really cool method to explain a complex topic, my instinct on reading mic-droppy, RLHF AI prose is to be dismissive? there's just something about the persistent mic drops and this-not-that writing that feels so cheap
I think it's because the explainer is passive, there's no interiority, it tells and doesn't show. plus, stylistically, if this were rewritten in second person (like most explainers are) it would make it a heck of a lot more readable:
'You order a coffee on your coffee shop's tablet. 211.4 ms later you see 'Order Confirmed'.
There's a world of complexity behind that status confirmation. Let's see how it all works.' etc
- felooboolooomba
> The person who clicked noticed no delay.
Just to be the "actually..." guy: People notice 200ms delay. It's just that in cases it doesn't cause any bad feelings."
- jonahrd
Am I crazy if for something like an online purchase, I kind of expect it to take a second or two to process the payment, so I would assume something went wrong if it was 200ms?
- hex4def6
>touchpad controller
>capacitance dip → interrupt raised
>hid driver report: x 512 · y 288 · button 1 down
>...
>One millisecond in, the click has passed through four pieces of software and nothing has left the laptop.
I'm going to press X to doubt.
There's no way you're getting from "finger touching glass" -> "chrome seeing a click" in one millisecond. Heck, I know for a fact that even the cap touch controller isn't going to be that quick.
I would believe it's closer to 40-50ms, E2E. Even if the captouch was instantaneous, 1ms latency latency is in the realm of RTOS, not a general-purpose OS feeding a bloated app like chrome.
- cloverich
I'm surprised at all the "200ms is slow" comments. I make many purchases online, don't we all? I can't remember the last time one took sub 1000ms; they usually take several. What are some of the websites you purchase from that truly complete a purchase in sub-200ms?
- beders
This is magnificent!
Gave me roller-coaster ride across 40 years of gathering knowledge about computers and networks.
I'm very jealous of whoever created that. Well done!
- joshstrange
> Violet marks the data as it moves, always top to bottom. Nothing else on the page uses that color.
Proceeds to use that color for tooltips, text color, headers, and more
This was a really cool visualization but that ^ bothered me way more than it should have.