UI is ok. UX needs to be improved. It tries to be modern and sleek, and it slightly achieved it. Too much use of shadow in the boxes and the number pagination below. I suggest to lessen the shadow distance as it's not really pretty. IMHO, there are unnecessary blank spaces that needs to be filled. Consider re-arranging it to lessen the blank spaces.
I love the transition from light mode to dark mode and vice versa. Good job with that. :D
When I visit a crypto ranking site, what I want to see are the list of cryptocurrencies immediately. At Koinju, you need to scroll down to find what you're looking for. Or wait for around 15 seconds and it will scroll down automatically (on desktop). On mobile it immediately scrolls down after 2 seconds.
If you go to each coin page, and resize your browser, you'll notice that the size of the chart isn't responsive. For example: https://koinju.io/crypto/nano, then try changing size of your browser window to 1199px width. Screenshot:
https://i.imgur.com/lyG2AvW.png
This needs to be fixed as it doesn't look good on anyone's perspective. :D
Loading speed is not that fast, and not that slow. But on my end, it constantly times out. Maybe it's just because of my ISP.
Pagespeed Insight grades for both mobile and desktop is above average. 60 on mobile and 80 on desktop.
https://developers.google.com/speed/pagespeed/insights/?url=https%3A%2F%2Fkoinju.io%2F&tab=mobile
TTFB needs to be improved, and DOM size needs to be reduced. Other suggestions are all mentioned in the Pagespeed Insight tools. Pagespeed suggested to use `renderToNodeStream()` or `renderToStaticNodeStream()` to reduce the server response time.
I always encounter "loading cryptocurrencies", then when it loads, it will show the message "An unexpected error has occurred.". Once again, I think this is just an isolated case on my end, as internet in the Philippines is terribly slow.
GTMetrix grade is above average as well. It loads at 7.8 seconds.
https://gtmetrix.com/reports/koinju.io/Mwof5io5
Fast websites should load less than a second. Worst is 2 seconds.
But yep, 7.8 seconds is ok. Coinmarketcap.com (https://gtmetrix.com/reports/coinmarketcap.com/uPiNnqcK) even loads slower at 53.5 seconds. Terrible, really terrible. So great job Koinju. But you can still improve your page speed by optimizing what needs to be optimized.
It seems that you're not leveraging browser caching of your static assets hosted on AWS. For instance:
koinju-charts-preprod.s3.eu-west-1.amazonaws.com/ada-cardano.png (expiration not specified)
koinju-charts-preprod.s3.eu-west-1.amazonaws.com/atom-cosmos.png (expiration not specified)
koinju-charts-preprod.s3.eu-west-1.amazonaws.com/band-band-protocol.png (expiration not specified)
Or use an SVG for charts, instead of images.
You should also serve scaled images, example of images that aren't scaled.
koinju-icons.s3-eu-west-1.amazonaws.com/cryptos/omg-omisego.png is resized in HTML or CSS from 128x128 to 27x35. Serving a scaled image could save 11.3KiB (94% reduction).
koinju-icons.s3-eu-west-1.amazonaws.com/cryptos/sushi-sushi.png is resized in HTML or CSS from 128x128 to 27x35. Serving a scaled image could save 6.4KiB (94% reduction).
koinju-icons.s3-eu-west-1.amazonaws.com/cryptos/usdc-usd-coin.png is resized in HTML or CSS from 128x128 to 27x35. Serving a scaled image could save 6.1KiB (94% reduction).
If it's more than 90% reduction to its current size, the it definitely needs to be scaled. Or use SVG or webp.
Your Yslow score is F on CDN. So... I strongly suggest that you use CDN on your static assets. I recommend MaxCDN / Stackpath, then combine it with Cloudflare.
I also notice some issues when you search. Maybe this only appears in slow internet connections, but I think you should check it out. For example when I search "NANO" it shows the NANO price with a Bitcoin logo. (https://twitter.com/pronewchaos/status/1313889586750222338) Kinda weird. But maybe, it's just because my internet connection is slow, or perhaps this is a bug that they didn't notice.
Overall, there are a lot of things that needs to be improved, but great job on the sleek + ergonomic UI. :)