koleo.pl

Readiness by lane

Green: koleo.pl. Thin bar: Trains & Public Transport peer median.

Priority fixes for koleo.pl

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

1. Priority 1 · Harden

   Certificate has more than 14 days left

   Observed: The certificate from Asseco Data Systems S.A. was due to expire on 2026-11-04 (11 days after the check).

   Why it matters: An expired certificate makes browsers show a full-page warning. Renewing well ahead of expiry leaves time to fix a failed renewal.

   What to do: Automate renewal with ACME (for example Let's Encrypt or your CDN's managed certificates) and add a renewal review to your release calendar so any certificate inside 21 days of expiry gets attention.

   98% of Trains & Public Transport peers do this. Limit: Certificate and protocol were observed from one vantage point; CDNs can present different certificates by region.

   Guide: HTTPS and TLS Guide for Website Owners

2. Priority 2 · Harden

   HSTS kept for at least a year

   Observed: Strict-Transport-Security was sent with a max-age of 180 days, below the one-year benchmark.

   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 Cloudflare: Enable HSTS under SSL/TLS > Edge Certificates > HTTP Strict Transport Security and raise max-age gradually.

   41% of Trains & Public Transport peers do this.

   Guide: HTTPS and TLS Guide for Website Owners

3. Priority 3 · Harden

   DMARC policy enforces quarantine or reject

   Observed: The DMARC policy for koleo.pl was p=none, which asks receivers to take no action on failing mail.

   What to do: Publish DMARC with p=none and a reporting address first, fix any legitimate senders that fail SPF or DKIM alignment, then move to quarantine and finally reject.

   40% of Trains & Public Transport peers do this.

   Guide: A Practical Website Health Check for Owners

4. Priority 4 · Accelerate

   Modern image formats in use

   Observed: The homepage had 98 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.

   On Cloudflare: Cloudflare Polish can convert images to WebP.

   28% of Trains & Public Transport peers do this.

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

What koleo.pl already does well

Practices fewer than half of Trains & Public Transport peers use.

• HTTP/3 advertisedHTTP/3 advertised.28% of peers
• Reachable over IPv6IPv6 address published.33% of peers
• Static files cached for 30 days or moreLong-lived caching on static files.38% of peers

What we saw

Homepage checked

https://koleo.pl/

Homepage response

HTTP 200

TLS

TLSv1.3, HTTP/2

Certificate

Asseco Data Systems S.A., 364-day validity, expiring 2026-11-04

CDN or edge

Cloudflare

Platform or framework

Nuxt

DNS operators

Cloudflare

HSTS

max-age 180 days, includeSubDomains, preload

DMARC policy

p=none

Homepage HTML

357 KB, br

Images on homepage

98 (jpg 206, png 29, svg 27)

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 Trains & Public Transport sites

• bahnhof.de59
• chalo.com59
• dd1.fr59
• doko-train.jp58
• rapidpass.com.bd59

Trains & Public Transport readiness benchmark