customer.io speed test — 20 Oct 2026
Measured from the wfix.shop server on 20 October 2026 at 13:08 UTC. Grade A (96/100), with the screenshots, the timings and the fixes that matter.
Grade
A
96/100
First byte (TTFB)258 msmeasured from this server
Fully loaded1.84 sfirst byte + slowest asset
Requests26document + assets
Page weight788.0 KBcompressed transfer
HTML document63.3 KBbr
ProtocolHTTP/3Vercel
Third-party27.4 KBother hosts
Where the first byte went
- DNS lookup 59 ms 23%
- TCP connect 36 ms 14%
- Server wait 164 ms 64%
Measured on the connection that fetched the HTML. Every other request on the page waits for the end of this bar before it can start.
How this page compares
First bytefaster than 83% of 4,999 pages tested here258 ms against a median of 449 ms
Page weightheavier than 56% of 4,999 pages tested here788.0 KB against a median of 650.3 KB
Fully loadedfaster than 50% of 4,999 pages tested here1.84 s against a median of 1.84 s
Requestssends more requests than 100% of 4,999 pages tested here26 against a median of 26
Every report published here is in this comparison, so it is a reference population of pages tested from one server - not a benchmark of the whole web.
What these numbers mean
- The first byte arrived in 258 ms. That is workable, and the cheapest win left is caching or a warmer connection.
- The page transfers 788.0 KB over 26 request(s). Images files are 92% of it, so resize and recompress the largest images before anything else.
- The HTML itself arrives br-compressed.
- It runs over HTTP/3, so the assets share a connection instead of opening one each.
Fix first: Render-blocking resources - Add defer or async to scripts that do not change the first paint, inline the critical CSS, and load the rest with media="print" plus an onload swap.
Read on one shared server, not a visitor's phone: use it to compare pages against each other, not as a promise about every connection. We fix what these tests find.
No screenshot for this report.
The headless browser did not capture this page when the test ran, so only the server measurements are shown.
Page weight by type
What the page is made of
Images 25 requests
724.7 KB 92%
Transfer size, compressed as sent. 26 request(s) in total, 788.0 KB across all of them.
Top issues
Render-blocking resources
high impact3 render-blocking resource(s) in the document head (1 script(s), 2 stylesheet(s)). The page cannot paint until each one arrives.
Fix: Add defer or async to scripts that do not change the first paint, inline the critical CSS, and load the rest with media="print" plus an onload swap.
Waterfall
Slowest requests
IMAGEScustomer.io/_next/image
1.59 s
IMAGEScustomer.io/_next/image
1.53 s
IMAGEScustomer.io/_next/image
1.49 s
IMAGEScustomer.io/_next/image
1.43 s
IMAGEScustomer.io/_next/image
1.43 s
IMAGEScdn.sanity.io/images/onirtmj2/production/4c21f6b6898…
1.20 s
IMAGEScdn.sanity.io/images/onirtmj2/production/6ad8e8e7de9…
1.20 s
IMAGEScdn.sanity.io/images/onirtmj2/production/16019fbc08e…
1.20 s
IMAGEScdn.sanity.io/images/onirtmj2/production/b43a6431082…
1.19 s
IMAGEScdn.sanity.io/images/onirtmj2/production/03ba17d6d44…
1.19 s
Each bar is one request's own response time, scaled to the slowest. Assets were fetched in parallel, so the bars overlap in real time rather than stacking. first party third party
| Request | Type | Status | Time | Size |
|---|---|---|---|---|
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2F9997b2df4198119080c883960e30be127ce545cc-1200x998.png%3Fw%3D1200%26h%3D998%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=640&q=80 | images | 200 | 1.59 s | 34.8 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2F04c20548d54a791364f269daff28f609dd40933a-1240x698.jpg%3Fw%3D1920%26h%3D1080%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=640&q=80 | images | 200 | 1.53 s | 29.8 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2Fc03d0a8873e8ec8cf52e921ed069e3b263b7a735-1200x1000.jpg%3Fw%3D1200%26h%3D1000%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=640&q=80 | images | 200 | 1.49 s | 40.5 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2F296d2479ac6b6405027cacd4cdc51853af0e83c5-1200x1000.png%3Fw%3D1200%26h%3D1000%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=640&q=80 | images | 200 | 1.43 s | 26.9 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2F46b451cf0aaa8e2bac5be40f31665748b7542a32-1200x1002.png%3Fw%3D1200%26h%3D1002%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=640&q=80 | images | 200 | 1.43 s | 36.9 KB |
| https://cdn.sanity.io/images/onirtmj2/production/4c21f6b6898a453db73ef77fcc37e4600a021622-283x113.svg 3rd party | images | 200 | 1.20 s | 1.2 KB |
| https://cdn.sanity.io/images/onirtmj2/production/6ad8e8e7de9ad70e9b9ea04fafc634d9f9dd7389-316x55.svg 3rd party | images | 200 | 1.20 s | 1.1 KB |
| https://cdn.sanity.io/images/onirtmj2/production/16019fbc08ecc85c8c1fc66d66eeb1a16f3cd3ca-300x72.svg 3rd party | images | 200 | 1.20 s | 1.3 KB |
| https://cdn.sanity.io/images/onirtmj2/production/b43a64310828a0d364d073093fc6404d65b7aec3-115x20.svg 3rd party | images | 200 | 1.19 s | 2.6 KB |
| https://cdn.sanity.io/images/onirtmj2/production/03ba17d6d44945e88c261740eb0f5c429ee01973-270x75.svg 3rd party | images | 200 | 1.19 s | 1.5 KB |
| https://cdn.sanity.io/images/onirtmj2/production/a286a1d4d435e1f0f527c5680f7474c659ed4f19-292x89.svg 3rd party | images | 200 | 1.19 s | 1.5 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2F46b451cf0aaa8e2bac5be40f31665748b7542a32-1200x1002.png%3Fw%3D1200%26h%3D1002%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=3840&q=80 | images | 200 | 1.18 s | 88.8 KB |
| https://cdn.sanity.io/images/onirtmj2/production/fca36e135c6b7f44ae3dc3de350c4d2f55c7d4a4-326x47.svg 3rd party | images | 200 | 1.18 s | 6.8 KB |
| https://cdn.sanity.io/images/onirtmj2/production/6a229db9b15fa49586e538d09d01ffe3f49693bd-274x72.svg 3rd party | images | 200 | 1.17 s | 1.8 KB |
| https://cdn.sanity.io/images/onirtmj2/production/6f15df0eac9cc25d700b1dc6fd2d01a2933e5659-532x85.svg 3rd party | images | 200 | 1.16 s | 1.6 KB |
| https://cdn.sanity.io/images/onirtmj2/production/1e0334dcfb8bac7ca10e25c6323b1195030cc2d4-328x65.svg 3rd party | images | 200 | 1.16 s | 3.3 KB |
| https://cdn.sanity.io/images/onirtmj2/production/3e56e0ac8b74754e5671a49fa9a3ccf5bce69bd6-317x76.svg 3rd party | images | 200 | 1.15 s | 2.1 KB |
| https://cdn.sanity.io/images/onirtmj2/production/78a7e067f3dc132fa53297755708bb80f2944a8c-215x80.svg 3rd party | images | 200 | 1.14 s | 1.6 KB |
| https://cdn.sanity.io/images/onirtmj2/production/3d4c1f7a79f52d932f114cc2d24e5f61809ef349-52x30.svg 3rd party | images | 200 | 1.14 s | 1.2 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2F04c20548d54a791364f269daff28f609dd40933a-1240x698.jpg%3Fw%3D1920%26h%3D1080%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=3840&q=80 | images | 200 | 1.13 s | 111.6 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2Fcf961b9276046e242cc2cd6c81a7691b985b1b77-2160x1215.png%3Fw%3D2160%26h%3D1215%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=3840&q=80 | images | 200 | 1.11 s | 82.9 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2Fcf961b9276046e242cc2cd6c81a7691b985b1b77-2160x1215.png%3Fw%3D2160%26h%3D1215%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=640&q=80 | images | 200 | 1.10 s | 23.0 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2Fc03d0a8873e8ec8cf52e921ed069e3b263b7a735-1200x1000.jpg%3Fw%3D1200%26h%3D1000%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=3840&q=80 | images | 200 | 1.07 s | 84.9 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2F296d2479ac6b6405027cacd4cdc51853af0e83c5-1200x1000.png%3Fw%3D1200%26h%3D1000%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=3840&q=80 | images | 200 | 1.04 s | 70.1 KB |
| https://customer.io/_next/image?url=https%3A%2F%2Fcdn.sanity.io%2Fimages%2Fonirtmj2%2Fproduction%2F9997b2df4198119080c883960e30be127ce545cc-1200x998.png%3Fw%3D1200%26h%3D998%26q%3D80%26fit%3Dfill%26auto%3Dformat&w=3840&q=80 | images | 200 | 1.03 s | 67.0 KB |
Report this page
Run this test on your own site
The same engine, free, with the screenshots and the fixes. No account needed.