How to validate links and images before sending?

A broken link kills credibility fast. One wrong URL and subscribers lose trust. That's why link validation has to be part of your pre-send ritual.

Automated link checking is your first pass. Most email rendering tools include link checkers that crawl your email and flag broken URLs, unexpected redirects, or links to blocklisted domains. They verify that every URL returns a successful response (HTTP 200 status). If you're using personalized or dynamic URLs with variable parameters, test with multiple subscriber profiles to make sure all variations resolve correctly. The automated tools do this in seconds.

Image validation has two parts. Technical. Are all images loading from their hosted locations? Are file sizes optimized for speed? Second, accessibility. Does every image have appropriate alt text? Here's a critical test: preview your email with images disabled and make sure it still reads clearly. Many subscribers see emails with images off first time, so your layout and content need to work without them.

But don't stop with automation. Click through every link manually at least once before major sends. Automated tools tell you if a link works. Manual testing tells you if it works right. Does tracking code get included? Does the landing page match your campaign message? Does the mobile version of that page actually work on a phone? These details matter.

Here's the workflow. Run your email through Litmus or a similar tool and check the link report. Review any flagged URLs. Then grab test devices and click through the most important links yourself. Check the destination, verify tracking is firing, confirm mobile pages display correctly. This takes 10 minutes for a normal send. For a big campaign, it's worth the time. One broken link is an invisible cost to your reputation.

Related: pre-send testing, dark mode testing, A/B testing.