@jdevalk
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Investor @emiliacapital • Founder @Yoast • Open Source aficionado currently playing with Astro & EmDash • Husband to Marieke • Father of 4 • 🇪🇺🇳🇱🇮🇹️️
Wijchen, Nederland
Joined March 2009
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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-sitemaps/
Joost de Valk retweeted
🫣 We have onboarded 3X more new paying customers in the past 2 and a half months compared to the total number of new customers we onboarded during the entire 12 months prior to that.
Yesterday, we pre-launched Patchstack for Lovable, Replit, Base44 and for any hosted NodeJS applications. Based on the volume of applications coming in, I can already tell the approach we've taken to protect these apps is what people have been waiting for.
Beyond excited for what's ahead of us.
For those who want to get early access - here's the link:
patchstack.com/ai-assisted-a…
PSA: XML sitemaps are about to lose their XSLT based "pretty” styling:
joost.blog/xml-sitemaps-with…
This is huge! Congrats to the Tailwind team and @adamwathan
The kind of story you can't make up or people would call it "overly romantic".
Perr Schuurs, injured for three years, make his comeback as a professional football player, and scores a goal with his first touch. All at my favorite team #NEC
people.kernel.org/monsieuric…
This is terrifying. And hilarious… but mostly terrifying.
I fear @OliverSild is right. And I’m not sure how we deal with that as a community. How _any_ open source community deals with this pressure.
The pressure being put on the commons is insane, and in many cases, not enough money is flowing into them to maintain them well.
I predict it's a matter of time when a 0 day will be dropped in WordPress core (vulnerability disclosed before core releases a fix for it). I already see people publishing the vulnerability reports they have sent via HackerOne to WordPress core, but which have not been fixed for years and taking into account all the AI built chains we're seeing, pretty sure some of them which were considered "meh" to fix will end up being something with a very real impact. There are a lot more security researchers now who can report pretty severe stuff thanks to AI and if they just keep getting responses that the issues are duplicates without seeing fixes going out they will just drop them publicly (we're already seeing this with plugins and with software from other ecosystems).
MCP 2026-07-28 shipped today: no more handshake, no more sessions.
That's how static sites already served MCP; the spec just caught up. What changed in my endpoint, why tools/list can now live on the CDN, and how my agent skills now ship over MCP:
joost.blog/mcp-goes-stateles…
For some of the work I’m doing I had to write down where I think websites are headed and what that means for SEO, and since I did, I decided to make a blog post out of it too:
joost.blog/future-of-the-web…
This... Is probably the best explanation of what SEOs call "keyword research". Write in the language your customers use.
There is the risk of navelgazing in this, so I would add one thing: talk to 100 or so prospective customers that didn't buy your product yet too.
Every marketing team should do this simple test.
At random, ask 100 of your existing customers to describe your product in their own words. No leading the witness.
Then look at how you describe your product on your site.
Don’t dismiss obvious differences by telling yourself, “They basically mean the same thing we do.”
Really look at the specific words. Really consider exactly what they’re saying and how they’re saying it. Compare that directly with the words you’re using, the descriptions you’re presenting, the picture you’re painting.
Then stare at the Grand Canyon.
When Dries wrote about License-only versus Stewarded Open Source, I knew I had to write a follow-on to that:
joost.blog/who-can-cut-you-o…
I wrote about this in the context of hosts, but this is happening everywhere and much more of a problem than people realize:
joost.blog/block-the-abuse/
Today I learned about Trusted Types:
specification.website/spec/s…
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/change…
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/
Two weeks ago I launched specification .website - a checklist for your site, I launched it with an MCP and built in some stats tracking thinking “this won’t get enormous usage”.
Boy was I wrong. 28,000+ tool calls in the last 24h and many more over the last two weeks…
What’s interesting to me is to see how fast people update their Claude and codex clients. And how… really all usage is either Claude or codex and really *nothing* else…
Stats system is still a bit crude & I should probably group the clients by name, but this shows it nicely:
ALT Stats from my MCP stats showing just Claude code and codex clients
Why is blog.schema.org blocking my Claude @danbri ?
