Calendars apps are incredibly hard to get right. So, with limited resources, in 2021 we had built Cron mobile app for iPhone and Android with React Native. We used custom Metal to get perf and it allowed us to re-use all the time zone math, grid mechanics, etc. from desktop via a ry.
Today, the @NotionHQ team unveils @NotionCalendar built natively from the ground up (at least I assume it’s today given this cute bunny greeted me on prod 🐰). It carries forward much of the Cron UI, like edge-swipe to add multiple time zones, event deduping, etc.
Been testing this for a few months and it has become my daily driver. Upgrade your calendar app today!
Today, the @NotionHQ team unveils @NotionCalendar built natively from the ground up (at least I assume it’s today given this cute bunny greeted me on prod 🐰). It carries forward much of the Cron UI, like edge-swipe to add multiple time zones, event deduping, etc.
Been testing this for a few months and it has become my daily driver. Upgrade your calendar app today!
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How I ran sub315 at yesterday’s NYC Marathon while commuting NY–SF every ~3 days for YC all summer and as a dad of a 1yo+3yo with a surgeon wife:
(All to say that running was like my priority #7 …)
The answer? I had AI analyze the heck out of my constant stream of data and via specialized coach in my pocket :–D
For training, it had my calendar, sleep, workout, heart rate — just about everything.
For the race, every mile I knew exactly what pace to run (see chart), what gel to take, and how much salt my body needed based on weather forecast.
Then the day off, I could just lock-in and have fun. Software for n=1 is incredible.
(All to say that running was like my priority #7 …)
The answer? I had AI analyze the heck out of my constant stream of data and via specialized coach in my pocket :–D
For training, it had my calendar, sleep, workout, heart rate — just about everything.
For the race, every mile I knew exactly what pace to run (see chart), what gel to take, and how much salt my body needed based on weather forecast.
Then the day off, I could just lock-in and have fun. Software for n=1 is incredible.
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vimeo.com/6238580 🐐
Marathon is a 20mi warmup followed by a 6mi race.
When freaking out "how can I sustain this pace," slow down mentally, which is not the same thing as slowing down physically, let the legs continue to spin.
Have A/B/C plan you can switch during race.
Marathon is a 20mi warmup followed by a 6mi race.
When freaking out "how can I sustain this pace," slow down mentally, which is not the same thing as slowing down physically, let the legs continue to spin.
Have A/B/C plan you can switch during race.
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@yishanzh @Paul_Rony @NotionCalendar Drag & drop reordering of time zones has been working for at at least five years (cron.com/changelog/2021…), until recently it must have been broken. Live demo of @Paul_Rony's request: youtu.be/dXxSaujKhms?si… (at 20:11)
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Old to-do (circa 2021) from the very first 1,000 Cronboardings. Did each personally & learned so much.
Good draft language! (highlighted)
Everything starts small.
Good draft language! (highlighted)
Everything starts small.
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Week complete.
Distance 108k · Time 9h · Elevation 1,134 m
Easy milage, Threshold intervals, Marathon pace.
Mostly Central Park, capping it in California.
Do hard things.
Distance 108k · Time 9h · Elevation 1,134 m
Easy milage, Threshold intervals, Marathon pace.
Mostly Central Park, capping it in California.
Do hard things.
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Life update: dropping the "Visiting" — I'm joining @ycombinator as a General Partner 🤩
YC was my first choice as a founder in 2019. Seven years later, I'm choosing it again.
This past year, I got to come full circle: working with founders through the W26 and S26 batches, ideas into products people love.
I'm incredibly excited to keep finding founders and helping them build the iconic companies of this generation 🔥
YC was my first choice as a founder in 2019. Seven years later, I'm choosing it again.
This past year, I got to come full circle: working with founders through the W26 and S26 batches, ideas into products people love.
I'm incredibly excited to keep finding founders and helping them build the iconic companies of this generation 🔥
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We’ve probably all seen Interstellar when it first came out.
Must watch again. If you’re a designer, an engineer, a founder, a dreamer — there’s so much creativity & inspiration in that story.
At the latest on your next flight, if they have it, go for it.
Must watch again. If you’re a designer, an engineer, a founder, a dreamer — there’s so much creativity & inspiration in that story.
At the latest on your next flight, if they have it, go for it.
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This “Wall of Products” reminded me of Apple’s “Wall of Apps.”
And it makes sense, the explosion of industrial products used to be the frontier of design.
Now that the one industrial product that matters is the smart phone, consumer design largely moved up the stack to apps.
And it makes sense, the explosion of industrial products used to be the frontier of design.
Now that the one industrial product that matters is the smart phone, consumer design largely moved up the stack to apps.
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Y Combinator's coming to Zürich tomorrow!
I'll be joining a panel hosted by Max Rumpf (Founder SID.ai, YC S23) on AI, research, startups & Swiss building between SFBA/Zürich.
→ Sign up below, only few more seats available: luma.com/c3c8b606
I'll be joining a panel hosted by Max Rumpf (Founder SID.ai, YC S23) on AI, research, startups & Swiss building between SFBA/Zürich.
→ Sign up below, only few more seats available: luma.com/c3c8b606
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FREITAG × AP
Instant goated combo 💚
Especially on a SWISS flight
Off to the motherland for design inspo
Instant goated combo 💚
Especially on a SWISS flight
Off to the motherland for design inspo
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S26 is an exceptional @ycombinator batch; everyone that meets the companies says so.
Honored to have worked closely with 36 of them this batch. Some will become generational companies, no doubt 🫡
Honored to have worked closely with 36 of them this batch. Some will become generational companies, no doubt 🫡
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Josh Kerr is one of the best runners in the world. Last month, he ran a mile in 3 minutes and 42.66 seconds, breaking a a world record that stood for 27 years.
Been following him for years (although at the end of the day in the head-to-head, I root for Ingebrigtsen ;). Three with his state of mind and his performance:
1) Journaling — Write down your perfect day.
Kerr's perfect day includes going to bed early and getting up early. Being outside and not being on the phone for at least the first 30 minutes each day. He finds it useful to write about the details "the little things" and the flow of the day he aspires to live. What does your perfect day look like?
2) Accept and learn from what feels hard or challenging.
Running can feel great but much of the time it is challenging. "I feel pretty bad at running most of the time… that's just the human element of the sport." Suggest not shying away from what feels difficult. How do you relate to the "hard stuff" in daily life?
3) Focus on an attitude of self-respect, not results.
"Effort is the only thing you can bring. Effort doesn't take talent. It doesn't take anything other than respect. I have a lot of respect for my own time and for the people that work hard for me. The biggest disrespect that you can give a coach or a team of people is just a lack of effort. That's what I try to show up and do every day. It's hard. It's very hard. But it's the least I can do on my end." How might you practice "right effort" — cultivating positive state of mind, appreciating effort and not over-emphasizing outcomes?
Been following him for years (although at the end of the day in the head-to-head, I root for Ingebrigtsen ;). Three with his state of mind and his performance:
1) Journaling — Write down your perfect day.
Kerr's perfect day includes going to bed early and getting up early. Being outside and not being on the phone for at least the first 30 minutes each day. He finds it useful to write about the details "the little things" and the flow of the day he aspires to live. What does your perfect day look like?
2) Accept and learn from what feels hard or challenging.
Running can feel great but much of the time it is challenging. "I feel pretty bad at running most of the time… that's just the human element of the sport." Suggest not shying away from what feels difficult. How do you relate to the "hard stuff" in daily life?
3) Focus on an attitude of self-respect, not results.
"Effort is the only thing you can bring. Effort doesn't take talent. It doesn't take anything other than respect. I have a lot of respect for my own time and for the people that work hard for me. The biggest disrespect that you can give a coach or a team of people is just a lack of effort. That's what I try to show up and do every day. It's hard. It's very hard. But it's the least I can do on my end." How might you practice "right effort" — cultivating positive state of mind, appreciating effort and not over-emphasizing outcomes?
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Friends don't let friends use GCal
I cannot understand why @googlecalendar does not recognize a phone number in the location field and just link it to a phone call vs. sending me to Google Maps to search for a phone number. I want to go work at Google for three hours just to fix this.
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Here's where we're at August 2026:
– Copilot etc.
↓ Agentic engineering ("vibe coding")
↓ Agent orchestration
↓ Loops
↓ Graphs
↓ Florps 😆 (see full video …)
– Copilot etc.
↓ Agentic engineering ("vibe coding")
↓ Agent orchestration
↓ Loops
↓ Graphs
↓ Florps 😆 (see full video …)
Caught up backstage w ClawFather @steipete; this is a packed one:
* Loops, Graphs, and Florps — what's latest in agentic engineering?
* Outie vs. Innie — avoid his personal vs. work agent fighting?
* Startup ideas in 2026 — what to build?
Lots of incredible zingers in here:
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Caught up backstage w ClawFather @steipete; this is a packed one:
* Loops, Graphs, and Florps — what's latest in agentic engineering?
* Outie vs. Innie — avoid his personal vs. work agent fighting?
* Startup ideas in 2026 — what to build?
Lots of incredible zingers in here:
* Loops, Graphs, and Florps — what's latest in agentic engineering?
* Outie vs. Innie — avoid his personal vs. work agent fighting?
* Startup ideas in 2026 — what to build?
Lots of incredible zingers in here:
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Cooking up ways to teach YC batches the nature of Product Quality.
iPod, Google Search, Instagram — these are singular products that touched 1B+ people, and their creators mastered the craft but critically:
Knew what to build, and what to delete.
iPod, Google Search, Instagram — these are singular products that touched 1B+ people, and their creators mastered the craft but critically:
Knew what to build, and what to delete.
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Susan's talk walking through the original designs of the Mac icons is live and a must-watch for every designer:
youtube.com/watch?v=YEvLKz…
youtube.com/watch?v=YEvLKz…
Never meet your heroes, they say —
But what if your hero is Susan Kare? 😊💛
Had the most wonderful conversation after she got off stage at @ycombinator Startup School. Full interview to follow.
In the meantime, pictures of her talk in thread 🧵
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One of the unique things about designers is that they just notice more; about products, people, places.
And this super power is also an absolute curse. They see every kerning that’s off, every misalignment in the world.
Here’s a crass example: this sign has offended me to no ked past it 😆 nobody else I’ve ever walked past it with seems to have noticed.
It obviously has a spelling mistake, maybe to fit horizontally?
What does the sign say in the first place? Isn’t the right an accessible ramp?!
And worst pet peeve of anyone with aesthetic sensibilities, zoom in, they’ve left the protective plastic film after installing. Like keeping the plastic on an iPhone screen 😭
And this super power is also an absolute curse. They see every kerning that’s off, every misalignment in the world.
Here’s a crass example: this sign has offended me to no ked past it 😆 nobody else I’ve ever walked past it with seems to have noticed.
It obviously has a spelling mistake, maybe to fit horizontally?
What does the sign say in the first place? Isn’t the right an accessible ramp?!
And worst pet peeve of anyone with aesthetic sensibilities, zoom in, they’ve left the protective plastic film after installing. Like keeping the plastic on an iPhone screen 😭
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