Kirby Performance and Media

Quick start

• Follow the workflow below, and run a full audit checklist when performance work spans multiple templates or plugins.

KB entry points

• kirby://kb/scenarios/55-cdn-asset-and-media-urls
• kirby://kb/scenarios/56-lazy-loading-images
• kirby://kb/scenarios/57-responsive-images-srcset
• kirby://kb/scenarios/58-fine-tune-page-cache
• kirby://kb/scenarios/79-conditional-loading-frontend-libraries

Required inputs

• Target pages/templates and performance symptoms.
• Image/media volume and CDN constraints.
• Acceptable cache settings or invalidation rules.

Audit checklist

• Identify templates that render large image sets or long listings.
• Check kirby://config/cache and kirby://config/thumbs for overrides.
• Verify media URLs, cache headers, and variant generation.

Measurement step

• Inspect Cache-Control headers and confirm generated /media variants exist.

CDN fallback rule

• If the CDN is unavailable, fall back to local asset/media URLs without breaking pages.

Common pitfalls

• Generating thumbnails in loops without srcset() or caching.
• Routing media through a CDN without preserving variants.

Workflow

1. Call kirby:kirby_init and read kirby://config/cache and kirby://config/thumbs.
2. Inspect templates/snippets that render large collections of images:

- kirby:kirbytemplatesindex - kirby:kirbysnippetsindex

1. Search the KB with kirby:kirby_search (examples: "cdn asset and media urls", "lazy loading images", "responsive images srcset", "fine tune page cache").
2. Apply minimal changes first:

- use srcset()/sizes for responsive images - add loading="lazy" and decoding="async" - adjust cache ignore rules via blueprint options or fields - route assets/media through a CDN when required

1. Verify output and caching behavior:

- kirby:kirbyrenderpage(noCache=true) for HTML - inspect generated media variants and cache headers in a browser