Wordpress - Caching riddles

When Caching Breaks Your WordPress REST API: A Debugging Story and Why Caching Still Matters For the past six months, my custom publishing pipeline has worked flawlessly. I write a blog post once in Markdown with YAML frontmatter, push it to Git, and a Jenkins-based CI/CD pipeline automatically publishes it to multiple platforms. WordPress serves as the canonical source, with the pipeline using the WordPress REST API to create or update posts, upload media, set tags, and handle everything else. Then, two days ago, everything stopped. The pipeline started throwing tracebacks on every run. Nothing in my code or setup had changed — only a new post was being published. Even after removing the new post, the errors persisted. A similar pipeline on another site broke at the same time. After a full day of troubleshooting, I narrowed it down: the WordPress REST API was returning completely empty responses for posts and tags endpoints. That left only two likely culprits — a recent WordPress core