Stoyan Stefanov
@stoyan.me
stoyan.me, PerfPlanet, "JavaScript Patterns", "React: Up & Running", YSlow, SmushIt. Formerly of Facebook, WebPageTest, Yahoo
New blog post about subsetting a ligature-heavy font highperformancewebfonts.com/read/subsett...
Almost always we subset based on text. But in my case, a more fine-tuned glyph-based approach saves 91% of bytes as opposed to 74% in the usual way. Worth it?
Almost always we subset based on text. But in my case, a more fine-tuned glyph-based approach saves 91% of bytes as opposed to 74% in the usual way. Worth it?
December 30, 2025 at 8:33 PM
New blog post about subsetting a ligature-heavy font highperformancewebfonts.com/read/subsett...
Almost always we subset based on text. But in my case, a more fine-tuned glyph-based approach saves 91% of bytes as opposed to 74% in the usual way. Worth it?
Almost always we subset based on text. But in my case, a more fine-tuned glyph-based approach saves 91% of bytes as opposed to 74% in the usual way. Worth it?
New blog post "Lazy-Loading Optional Fonts with Native Browser API" describing a wee trick I do on sightread.org to load music glyphs, optionally
highperformancewebfonts.com/read/lazy-lo...
highperformancewebfonts.com/read/lazy-lo...
December 24, 2025 at 7:21 PM
New blog post "Lazy-Loading Optional Fonts with Native Browser API" describing a wee trick I do on sightread.org to load music glyphs, optionally
highperformancewebfonts.com/read/lazy-lo...
highperformancewebfonts.com/read/lazy-lo...
Bug or a feature: selecting code in the devtools console makes some tokens black rather than white?
December 2, 2025 at 7:00 PM
Bug or a feature: selecting code in the devtools console makes some tokens black rather than white?
perforomance.run() everybody! The latest API available to folks visiting for #perfnow
October 29, 2025 at 3:58 PM
perforomance.run() everybody! The latest API available to folks visiting for #perfnow
Ha! @11ty.dev folks have opened a Beverly Hills location /cc @zachleat.com
July 11, 2025 at 8:33 PM
Ha! @11ty.dev folks have opened a Beverly Hills location /cc @zachleat.com
Not the web-type of performance
June 16, 2025 at 11:19 PM
Not the web-type of performance
performance.now() conference by @ppkoch.bsky.social and friends is back again for another edition: perfnow.nl
2 days, single-track, 100% web performance geekout happening 30th and 31st of October in Amsterdam. First 9 speakers announced, tickets on sale now.
2 days, single-track, 100% web performance geekout happening 30th and 31st of October in Amsterdam. First 9 speakers announced, tickets on sale now.
May 26, 2025 at 10:33 PM
performance.now() conference by @ppkoch.bsky.social and friends is back again for another edition: perfnow.nl
2 days, single-track, 100% web performance geekout happening 30th and 31st of October in Amsterdam. First 9 speakers announced, tickets on sale now.
2 days, single-track, 100% web performance geekout happening 30th and 31st of October in Amsterdam. First 9 speakers announced, tickets on sale now.
highperformancewebfonts.com/read/pick-ch...
A quick JS snippet that adds a feature to fontdrop.info to hand pick characters for subsetting with Glyphhanger. You click around and get a command generated that looks like:
$ glyphhanger --format=woff2 --subset="font.otf" --whitelist="U+0025,U+0026...
A quick JS snippet that adds a feature to fontdrop.info to hand pick characters for subsetting with Glyphhanger. You click around and get a command generated that looks like:
$ glyphhanger --format=woff2 --subset="font.otf" --whitelist="U+0025,U+0026...
May 25, 2025 at 5:45 PM
highperformancewebfonts.com/read/pick-ch...
A quick JS snippet that adds a feature to fontdrop.info to hand pick characters for subsetting with Glyphhanger. You click around and get a command generated that looks like:
$ glyphhanger --format=woff2 --subset="font.otf" --whitelist="U+0025,U+0026...
A quick JS snippet that adds a feature to fontdrop.info to hand pick characters for subsetting with Glyphhanger. You click around and get a command generated that looks like:
$ glyphhanger --format=woff2 --subset="font.otf" --whitelist="U+0025,U+0026...
Font sizing intensifies
April 25, 2025 at 8:14 PM
Font sizing intensifies
Read in 2025 so far, in an attempt to work on my attention span
April 3, 2025 at 5:53 PM
Read in 2025 so far, in an attempt to work on my attention span
I need to make like a 100 slides for a class I'm taking and I found this little tool is perfect www.markdowntoolbox.com/tools/conver...
March 31, 2025 at 10:02 PM
I need to make like a 100 slides for a class I'm taking and I found this little tool is perfect www.markdowntoolbox.com/tools/conver...
I found one here (next to Firebug and something called "PageTest" :D ) calendar.perfplanet.com/2009/perform...
February 18, 2025 at 7:37 PM
I found one here (next to Firebug and something called "PageTest" :D ) calendar.perfplanet.com/2009/perform...
getting all "scientific" on linkedin's URL shortening logic. Seems like URLs > 26 characters are shortened in posts, but left alone in comments
February 14, 2025 at 7:03 PM
getting all "scientific" on linkedin's URL shortening logic. Seems like URLs > 26 characters are shortened in posts, but left alone in comments
Put this in your console:
setInterval = setTimeout = requestAnimationFrame = console.log
... end you might be stunned, nay, horrified by what's happening in your app, especially with third-party code
(inspired by @andydavies.me)
setInterval = setTimeout = requestAnimationFrame = console.log
... end you might be stunned, nay, horrified by what's happening in your app, especially with third-party code
(inspired by @andydavies.me)
February 11, 2025 at 8:43 PM
Put this in your console:
setInterval = setTimeout = requestAnimationFrame = console.log
... end you might be stunned, nay, horrified by what's happening in your app, especially with third-party code
(inspired by @andydavies.me)
setInterval = setTimeout = requestAnimationFrame = console.log
... end you might be stunned, nay, horrified by what's happening in your app, especially with third-party code
(inspired by @andydavies.me)
I hung out in the Chicago public library today and I found someone has checked out one of my books. I'm torn between being proud someone is reading or feeling guilty and responsible for the person reading a 9-year old book. I mean the second edition feels old, let alone the 1st
February 7, 2025 at 5:00 AM
I hung out in the Chicago public library today and I found someone has checked out one of my books. I'm torn between being proud someone is reading or feeling guilty and responsible for the person reading a 9-year old book. I mean the second edition feels old, let alone the 1st
"Which local fonts can I use?" writeup, official docs and a web app to gather field data so we can have an authoritative answer to this question now and in the future highperformancewebfonts.com/read/which-l...
February 6, 2025 at 5:49 AM
"Which local fonts can I use?" writeup, official docs and a web app to gather field data so we can have an authoritative answer to this question now and in the future highperformancewebfonts.com/read/which-l...
New blog post: "First timid steps in Rust" www.phpied.com/first-timid-...
1. Install Rust
2. A new project
3. Add dependencies to Cargo.toml
4. All ok so far?
5. Tweaks in src/main.rs
6. (Optional, VSCode only) install rust-analyzer
Rust in peace!
1. Install Rust
2. A new project
3. Add dependencies to Cargo.toml
4. All ok so far?
5. Tweaks in src/main.rs
6. (Optional, VSCode only) install rust-analyzer
Rust in peace!
February 1, 2025 at 8:06 PM
New blog post: "First timid steps in Rust" www.phpied.com/first-timid-...
1. Install Rust
2. A new project
3. Add dependencies to Cargo.toml
4. All ok so far?
5. Tweaks in src/main.rs
6. (Optional, VSCode only) install rust-analyzer
Rust in peace!
1. Install Rust
2. A new project
3. Add dependencies to Cargo.toml
4. All ok so far?
5. Tweaks in src/main.rs
6. (Optional, VSCode only) install rust-analyzer
Rust in peace!
I'm having troubles uploading a video. It's an MP4 encoded by Handbrake that seems to work in QuickTime, linkedIn, etc. I'm on Firefox @support.bsky.team
February 1, 2025 at 8:02 PM
I'm having troubles uploading a video. It's an MP4 encoded by Handbrake that seems to work in QuickTime, linkedIn, etc. I'm on Firefox @support.bsky.team
My attempt at clarifying what we mean when we say font, font-family, font-face, typeface, etc.
highperformancewebfonts.com/read/font-ja...
highperformancewebfonts.com/read/font-ja...
January 27, 2025 at 8:13 AM
My attempt at clarifying what we mean when we say font, font-family, font-face, typeface, etc.
highperformancewebfonts.com/read/font-ja...
highperformancewebfonts.com/read/font-ja...
Today's mini-post on fonts turned out not so mini. A look into the past and future of `-apple-system` and `BlinkMacSystemFont`: highperformancewebfonts.com/read/ditch-B...
January 25, 2025 at 8:37 AM
Today's mini-post on fonts turned out not so mini. A look into the past and future of `-apple-system` and `BlinkMacSystemFont`: highperformancewebfonts.com/read/ditch-B...
New mini-post, this time on extreme font subsetting highperformancewebfonts.com/read/extreme...
January 24, 2025 at 8:14 AM
New mini-post, this time on extreme font subsetting highperformancewebfonts.com/read/extreme...
There *is* a solution to 🧭 Safari's annoying insistence of adding its little triangle icon to <details><summary> and it's
summary::-webkit-details-marker {
display: none;
}
summary::-webkit-details-marker {
display: none;
}
January 23, 2025 at 8:39 AM
There *is* a solution to 🧭 Safari's annoying insistence of adding its little triangle icon to <details><summary> and it's
summary::-webkit-details-marker {
display: none;
}
summary::-webkit-details-marker {
display: none;
}
A quick note on the importance of adding `crossorigin` when -preloading fonts: highperformancewebfonts.com/read/on-the-...
Otherwise you get duplicate font downloads and the preload is unused
Otherwise you get duplicate font downloads and the preload is unused
January 23, 2025 at 8:23 AM
A quick note on the importance of adding `crossorigin` when -preloading fonts: highperformancewebfonts.com/read/on-the-...
Otherwise you get duplicate font downloads and the preload is unused
Otherwise you get duplicate font downloads and the preload is unused