Joost de Valk

I built a Chrome extension to keep XML sitemaps readable. It turned into a bug finder. Adobe: canonicals pointing at a __template__ page. Man City: ex-players' pages that 404. X: robots.txt links to a sitemap that isn't there. Semrush: nested indexes. joost.blog/broken-sitem...

PSA: XML sitemaps are about to lose their XSLT based "pretty” styling: joost.blog/xml-sitemaps...

Today I learned about Trusted Types: specification.website/spec/securit... Which looks like a great way to prevent XSS in many cases. There are so many specifications like this I didn't know about before building this site...

PSA: I’ve been shipping new specs almost daily: specification.website/changelog/ I have an agent running daily that proposes new pages as new stuff becomes baseline across browsers etc. I’d suggest setting up a routine to check your websites against the changed spec regularly.

Last week, Google introduced Open Knowledge Format (OKF). This week, it introduced Agentic Resource Discovery (ARD). You'd think one would point to the other. You'd be wrong. It could though, with a simple fix, which I've proposed: joost.blog/okf-ard/

This week I shipped an MCP so AI agents could read my new specification .website. Also this week, one of my hosts shipped a CAPTCHA on another of my sites. To keep the agents out. Only one of us is reading the room. joost.blog/block-the-ab...

Launching specification.website. A platform-agnostic spec of what a good website does: SEO, accessibility, security, agent-readiness, performance, privacy, i18n. Every claim cites a source. Ships with a checklist, llms.txt, MCP server, and Agent Skill. Free. Open Source.

I spent over a year on FAIR (the federated WordPress alternative). The lesson: Open Source First in procurement isn't enough without funding the commons it depends on. Why I'm signing the SUSE letter to the EU, and what's missing from it: joost.blog/open-source-...

I recently built a bot tracking dashboard for my blog. Then when I looked at it today, I realized that it was reporting "visitors" that my (Plausible) analytics was not showing me... Which led me to think: what is a visitor, these days? joost.blog/what-is-a-vi...

FAQ schema died twice from spam. The second time was last Wednesday. The fix is a new schema .org type: FAQSection. I filed it. joost.blog/faq-schema-c...

Vol. XV: the 15th version of my blog since June 2004 (following pretty quickly after the previous one). I got rid of the AI-generated post images, picked Klim's Domaine and Pitch fonts to do the work instead, and built proper plumbing for longer writing. joost.blog/vol-xv/

WordPress 7.0 ships with AI, without real-time collaboration. The right call, just five weeks too late. The same answer was visible on March 31, when the cycle was extended for RTC. 7.0 could have shipped on its original April 9 date with the much needed AI features.

One of our portfolio companies asked me for help on a domain migration, and when I sent them my input, I realized I had never written about this, even though I've spoken about this a lot. So, here it is, my guide to how to do SEO domain migrations: joost.blog/seo-domain-m...

My blog scored 25/100 on @Cloudflare's isitagentready .com. A few hours later: 83. Wrote up the full stack: markdown content negotiation, Content Signals, Link headers, an API catalog, MCP, WebMCP. Plus where the scoring gets it wrong. joost.blog/agent-ready/

I posted about self-updating skills. I had searched and not found a better method, but asked for input. And I got it! So now, the updated version of my post tells you how to make your skills update easily: joost.blog/self-updatin...

Agent skills ship as loose folders. No npm, no registry. You have no way to tell users they're running a stale copy. I taught each of mine to check itself and install its own update, at the moment you invoke it. joost.blog/self-updatin...

When The SEO framework tweeted about the usage of llms.txt and that being a reason not to implement it, I had to write a post: joost.blog/standards-do...

I built Yoast SEO. I ran my blog on WordPress for years. Then yesterday I moved it to static HTML. Everything that matters, SEO, search, schema, is still there. What I dropped was the overhead. Do you actually need a CMS? For quite some sites: no. joost.blog/do-you-need-...

Been productive today at #CFHack2026, working on the FAIR for TYPO3 project, already got a PR merged in AspireCloud. Also reviewed the TYPO3 Extension Repository and wrote a bunch of design & UX suggestions for it: typo3-redesign.pages.dev #CFHack is such a great start to #Cloudfest!

"It's good to start your exercises with a little stretching." So we've completed a stretch goal before the main goal. We created a proposal for a redesign of the @typo3.com extension pages. Find it at typo3-redesign.pages.dev #CloudFest #CFHack #FAIRxTYPO3

I found myself needing to get Obsidian doc from my Openclaw agent, and not wanting to search for the doc it created or updated for me. So... I created a solution, https links to your Obsidian vault: joost.blog/obsidian-age...

AI will confidently sign off on anything. The question is whether you will too. joost.blog/healthy-doubt/

I've been working on a fun idea; OpenClaw is cool, but i wanted to take some of those autonomous ideas and apply them to a web app. So... I wrote an autonomous feedback agent: joost.blog/autonomous-f...

When @cloudflare.social introduced Markdown for Agents today, I was grinning. I'd been building the exact same thing, but for #WordPress, with almost exactly the same approach - this one works even if you're not on Cloudflare: joost.blog/markdown-alt...

Over the last few days, we've seen a good discussion about what #WordPress needs to be relevant in the current age. I think it boils down to two things: we need good, capable *and empowered* product and marketing teams. progressplanner.com/wordpress-pr...

88, but then I went and searched for the ones I didn't know and learned a new thing or 26 as i really didn't know most of them 😅️

Might be time to find the best open source alternative for SubStack and *own your own subscribers and content*. This will inevitably lead to higher prices, and probably to more barriers to getting your data out too…

Today at #OSSummit @joost.blog and I with @fair.pm announced our open call to @linuxfoundation.org members to join a new directed fund to ensure a true #OpenSource #CMS ecosystem for generations to come! Get in touch to Join!

Just gotten off stage presenting about @fair.pm at the Linux Foundation’s #OSSummit together with @marucchi.com - we’re starting the conversations with funders of our project today.

We're delighted to launch the FAIR Package Manager with the Linux Foundation - read our announcement and come collaborate with us! #FAIRPM www.linuxfoundation.org/press/linux-...

Is WordPress innovation in plugins slowing down? In this post Marieke and I explore why new plugins struggle to gain traction and how established ones dominate and what that means for innovation. Walking around #WCEU today, I realized that I *really* needed to publish: joost.blog/innovation-i...

It's time to fix the image of WordPress and its security: progressplanner.com/time-to-fix-...

We made SEO easier for everyone. That was the goal. But in the process, we helped flood the web with content. This is a reflection on what worked, what didn’t, and what we can learn from it. joost.blog/unintended-c...

Not everything needs AI. But WordPress needs AI-ready infrastructure. Read my thoughts: progressplanner.com/wordpress-ne...

We've built something cool at @progressplanner.com over the last few weeks: an integration with Yoast SEO, to give you lots of recommendations to improve your Yoast SEO setup: progressplanner.com/progress-pla...