What is Cache Busting?
Cache busting is a web development technique that prevents browsers and content delivery networks (CDNs) from serving outdated versions of website files. When a user visits a webpage, their browser stores copies of images, stylesheets, and scripts locally. Without cache busting, visitors might see old content even after you've updated your landing page – a critical issue for time-sensitive campaigns.
Why Cache Busting Matters for Landing Pages
For media agencies running campaigns, cache busting is essential to campaign performance. When you launch a new creative, update messaging, or fix conversion-blocking issues on a landing page, you need those changes live immediately. Without cache busting, some users see the old version while others see the new one, skewing your analytics and wasting ad spend on outdated experiences.
This is particularly important for UK-based agencies running paid media campaigns where every impression counts. If your ads direct users to a landing page, but half your audience sees a cached version with broken CTAs or outdated offers, you're losing conversions and ROI.
How Cache Busting Works
The most common approach adds a unique identifier to file URLs:
- Query strings:
style.css?v=1.2.3orscript.js?timestamp=1699564800 - Filename versioning:
style.min.abc123def.css(automatically generated by build tools) - Header-based methods: Setting HTTP cache-control headers to prevent caching entirely
Modern development frameworks like React, Vue, and Next.js handle this automatically during the build process, but understanding the principle helps you troubleshoot campaign issues.
When You Need Cache Busting
Implement cache busting when: - Launching new landing page variations for A/B testing - Updating creative assets mid-campaign - Fixing conversion funnel issues that require immediate fixes - Running time-sensitive promotions or seasonal campaigns - Modifying form fields or CTAs that affect performance
Best Practices
Work with your development team to ensure cache busting is configured in your deployment pipeline. For agencies, this means coordinating with your web technology partners before campaign go-live. Document when cache busting was deployed so you can accurately attribute performance changes to creative updates rather than technical issues.
When troubleshooting unexpected landing page performance dips, always check whether cached versions might be affecting your data. Clear browser cache or use incognito/private browsing to verify your latest changes are live.