kayak.es

Readiness by lane

Green: kayak.es. Thin bar: Travel Bookings & Trip Planning peer median.

Priority fixes for kayak.es

Ordered by impact and by how common each practice is among peers.

1. Priority 1 · Harden

   HSTS kept for at least a year

   Observed: Strict-Transport-Security was sent with a max-age of 126 days, below the one-year benchmark.

   Why it matters: HSTS tells browsers to use HTTPS for your host on every later visit, which removes the window where a first HTTP request can be intercepted.

   What to do: Send Strict-Transport-Security on HTTPS responses. Start with a short max-age (for example 300 seconds), confirm every subdomain works over HTTPS, then raise it in steps to 31536000. Add includeSubDomains only when all subdomains are HTTPS. HSTS preload is optional and hard to undo; hstspreload.org itself does not recommend it by default.

   On Fastly: Add the header in VCL or a header rule as described in Fastly's HSTS guide.

   46% of Travel Bookings & Trip Planning peers do this. Limit: Read from the homepage response only; other pages or regions may send different headers.

   Guide: HTTPS and TLS Guide for Website Owners

2. Priority 2 · Accelerate

   Modern image formats in use

   Observed: The homepage had 78 images and none used WebP or AVIF.

   What to do: Serve WebP or AVIF with a JPEG or PNG fallback, either through an image CDN or by generating both formats at build time.

   41% of Travel Bookings & Trip Planning peers do this.

   Guide: AVIF, WebP, JPEG, and PNG: Choose the Right Image Format

3. Priority 3 · Accelerate

   Offscreen images lazy-loaded

   Observed: The homepage had 78 images and none used loading="lazy".

   What to do: Add loading="lazy" to images below the fold. Do not lazy-load the main hero image, because that delays the largest visible element.

   62% of Travel Bookings & Trip Planning peers do this.

   Guide: Lazy Loading Without Broken Pages

4. Priority 4 · Accelerate

   HTTP/3 advertised

   Observed: The homepage did not advertise HTTP/3 through an Alt-Svc header.

   What to do: Turn on HTTP/3 at your CDN. Browsers fall back to HTTP/2 automatically, so the risk is low.

   33% of Travel Bookings & Trip Planning peers do this.

   Guide: CDN Guide for Website Owners

What kayak.es already does well

Practices fewer than half of Travel Bookings & Trip Planning peers use.

• Nameservers spread across providersNameservers spread across more than one operator.13% of peers
• security.txt publishedsecurity.txt with a contact found.17% of peers
• Content Security Policy presentContent-Security-Policy present.30% of peers

What we saw

Homepage checked

https://www.kayak.es/

Homepage response

HTTP 200

TLS

TLSv1.3, HTTP/2

Certificate

Let's Encrypt, 89-day validity, expiring 2026-11-27

CDN or edge

Fastly

DNS operators

3 self-run or other nameserver domains

HSTS

max-age 126 days, preload

DMARC policy

p=reject

Homepage HTML

1,668 KB, br

Images on homepage

78 (svg 1)

Limits: homepage only, one location, one moment. Header checks reflect the homepage response; other pages may differ.

Stack and providers

Seen in the homepage response, certificate and DNS. Provider pages compare how their customers configure the same checks.

All 31 checks

Select a gap for the method and fix. How each check works

Compare with other Travel Bookings & Trip Planning sites

• kayak.co.uk80
• kayak.com.br80
• kayak.com.co80
• kayak.fr80
• visitabudhabi.ae80

Travel Bookings & Trip Planning readiness benchmark