Niels Leenheer
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html5test.com
Niels Leenheer
@html5test.com
CTO of Salonhub. Creator of http://html5test.com, writes at http://nielsleenheer.com, team @FronteersConf, Google Developers Expert, Invite me to speak at your event.
As I prepare to go back to Tromsø airport for my flight home, I still can't believe what I witnessed last night. There are a handful of nights that I will remember for the rest of my life, and this is one of them. Yesterday I felt pure joy and you could hear it across that whole small beach.
January 11, 2026 at 6:23 AM
30 minutes ago in Tromsø. The CME has arrived @vincentledvina.bsky.social
January 10, 2026 at 8:58 PM
Me walking to the pickup point of the Northern Lights tour…
January 10, 2026 at 4:20 PM
Yesterday was another great night for the Northern Lights here in Tromsø. Very different from the night before, but just as beautiful. One more night to go 🤞🏻
January 10, 2026 at 11:00 AM
Took a second camera with me this trip to shoot time-lapses. Just a few quick renders, but really satisfied with the result. This is of course speed up, quite a bit. But the northern lights were really dancing yesterday. Swirling and moving right before your eyes.
January 9, 2026 at 10:20 AM
Arrived at Schiphol airport for my early morning flight to Tromso to see the Northern Lights.

✅ Looks like flights are resuming tomorrow
✅ 3 nights of clear skies predicted
✅ 3 nights of solar activity predicted

No guarantees on any of those, so🤞

This was last years trip:
January 7, 2026 at 6:26 PM
I bought a turntable. Yes… I am that old.
December 6, 2025 at 7:56 PM
2015 was the first year I attended Beyond Tellerrand and I can’t remember a single edition that was not absolutely and completely inspiring. So many fantastic talks and speakers over the years. Such an amazing community.

You should become a friend of the conference. I have.
December 2, 2025 at 8:17 PM
After an incredibly busy month of traveling I am finally on my way home. Last trip of the year, now time for rest and family.

Malta was great! Thanks DevFest Malta for having me.
November 27, 2025 at 5:24 AM
Oooh. This is incredibly useful. Just the other day I tried if inherit works in a calc() function - it obviously doesn’t. But now inherit() does!
inherit() is now available to play with in Chrome Canary.

Here's some writing I did about it earlier:

How CSS inherit() Could Simplify Design Systems
www.alwaystwisted.com/articles/mak...

How inherit() Can Simplify Border‑Radius for Components
www.alwaystwisted.com/articles/mak...

🙏🖤
November 25, 2025 at 3:08 PM
🔥🔥🔥

Lowest setting. CSS powered flamethrower!

Yes, it is really controlled by CSS. I can add MIDI inputs. Then use CSS to trigger animations and output the result to DMX for controlling the flamethrower.
November 18, 2025 at 2:44 PM
Current status: working on side projects until the Cloudflare issue has been solved.
November 18, 2025 at 2:21 PM
DevFest Warsaw is about to start. This is such a lovely space #devfest2025 #devfestwarsaw #googledevelopers
November 15, 2025 at 9:34 AM
Ren x The Skinner Brothers - Pink Heineken
YouTube video by Ren
youtu.be
November 14, 2025 at 7:31 PM
Arrived in Warsaw this evening for my penultimate conference of the year. Tomorrow DevFest Warsaw, then in a week and a half DevFest Malta.

Tonight a quiet night. We’re halfway November and I have only slept 4 nights in my own bed. I’ll need a couple of months rest after this.

#devfestwarsaw
November 14, 2025 at 5:31 PM
Okay, one more. I just loooooove the reflection here. So good. Doesn’t look like shit at all. No siree, ship it!
November 14, 2025 at 1:16 PM
Reposted by Niels Leenheer
Most relatable conference talk silde ever, courtesy of @html5test.com at #HalfStack
November 12, 2025 at 10:19 PM
On my way to Heathrow after another fantastic edition of @halfstackconf.bsky.social.

Happy with how my talk about Baseline went and then I did another unplanned 10 minute talk about one of my side projects that I literally wrote the night before, after the speaker dinner 😅
November 13, 2025 at 9:55 AM
Reposted by Niels Leenheer
It’s alive and on stage! cc: @nerdy.dev
November 12, 2025 at 12:43 PM
Just got home. First thing my 11-year old said to me: Dad, did you buy a flamethrower…?

Eh. Yes. Yes, I did. 🔥
November 8, 2025 at 3:31 PM
Almost home again after a couple of amazing days at @beyondtellerrand.com. Thank you so much @marcthiele.com!

It was so lovely seeing everybody again. After spending a couple hours at home I am off again to London for @halfstackconf.bsky.social and then straight to Warsaw for DevFest.
November 8, 2025 at 1:58 PM
@nerdy.dev This is happening. MIDI → CSS → DMX → 🔥
November 8, 2025 at 10:03 AM
Reposted by Niels Leenheer
#js developers 📣! There's still time to sign up for @halfstackconf.bsky.social London on Wed 12th November. There's some great talks on the list, including myself talking about #vectorsearch.

Here's my 10% off code if you still haven't got your 🎫 (😱):

ti.to/halfstack/ha...

See you there! 👋
November 5, 2025 at 12:31 PM
Looking for some random thing on AliExpress when suddenly… Hey! I could use a flame thrower! It would be fun to connect it to the web and…
November 5, 2025 at 10:02 AM
I guess Deutsche Bahn is going to Deutsche Bahn. Good decision to travel the day before. I will be late, but I’ll get to Berlin.

Lessons learned from last year visiting @beyondtellerrand.com where I missed the first two talks and got stranded in the middle of the night on my way back home.
November 5, 2025 at 9:50 AM