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Authentication on the web is a complicated problem. If you’re going to do it yourself, there’s a lot you have to take into consideration. But odds are, you’re building an app whose core offering has nothing to do with auth. You don’t care about auth. It’s an implementation detail. So rather than spend your precious time solving the problem of auth, you pay someone else to solve it. That’s the value of SaaS. What would be the point of paying for an authentication service, like workOS, then re-implementing auth on your own? They have dedicated teams working on that problem. It’s unlikely you’re going to do it better than them and still deliver on the product you’re building. There’s a parallel here, I think, to building stuff in the browser. Browsers provide lots of features to help you deliver good websites fast to an incredibly broad and diverse audience. Browser makers have teams of people who, day-in and day-out, are spending lots of time developing and optimizing new their offerings. So if you leverage what they offer you, that gives you an advantage because you don’t have to build it yourself. You could build it yourself. You could say “No thanks, I don’t want what you have. I’ll make my own.” But you don’t have to. And odds are, whatever you do build yourself, is not likely to be as fast as the highly-optimized subsystems you can tie together in the browser. And the best part? Unlike SasS, you don’t have to pay for what the browser offers you. And because you’re not paying, it can’t be turned off if you stop paying. @view-transition, for example, is a free API that’ll work forever. That’s a great deal. Are you taking advantage? Email · Mastodon · Bluesky
I have a standing desk that goes up and down via a manual crank. I’ve had it for probably ten years. Every time I raise or lower that thing, it gets my blood pumping. I often think: “I should upgrade to one of those standing desks that goes up and down with the push of a button.” Then there’s the other voice in my head: “Really? Are you so lazy you can’t put your snacks down, get out of your comfy chair, in your air conditioned room, and raise or lower your desk using a little elbow grease? That desk is just fine.” While writing this, I get out of my chair, star the timer, and raise my desk to standing position. 35 seconds. That’s the cost: 35 seconds, and an elevated heart rate. As I have many times over the last ten years, I recommit to keeping it — mostly as a reminder that it’s ok to do some things manually. Not everything in my life needs to be available to me at the push of a button. Email · Mastodon · Bluesky
(I present to you my stream of consciousness on the topic of casing as it applies to the web platform.) I’m reading about the new command and commandfor attributes — which I’m super excited about, declarative behavior invocation in HTML? YES PLEASE!! — and one thing that strikes me is the casing in these APIs. For example, the command attribute has a variety of values in HTML which correspond to APIs in JavaScript. The show-popover attribute value maps to .showPopover() in JavaScript. hide-popover maps to .hidePopover(), etc. So what we have is: lowercase in attribute names e.g. commandfor="..." kebab-case in attribute values e.g. show-popover camelCase for JS counterparts e.g. showPopover() After thinking about this a little more, I remember that HTML attributes names are case insensitive, so the browser will normalize them to lowercase during parsing. Given that, I suppose you could write commandFor="..." but it’s effectively the same. Ok, lowercase attribute names in HTML makes sense. The related popover attributes follow the same convention: popovertarget popovertargetaction And there are many other attribute names in HTML that are lowercase, e.g.: maxlength novalidate contenteditable autocomplete formenctype So that all makes sense. But wait, there are some attribute names with hyphens in them, like aria-label="..." and data-value="...". So why isn’t it command-for="..."? Well, upon further reflection, I suppose those attributes were named that way for extensibility’s sake: they are essentially wildcard attributes that represent a family of attributes that are all under the same namespace: aria-* and data-*. But wait, isn’t that an argument for doing popover-target and popover-target-action? Or command and command-for? But wait (I keep saying that) there are kebab-case attribute names in HTML — like http-equiv on the <meta> tag, or accept-charset on the form tag — but those seem more like legacy exceptions. It seems like the only answer here is: there is no rule. Naming is driven by convention and decisions are made on a case-by-case basis. But if I had to summarize, it would probably be that the default casing for new APIs tends to follow the rules I outlined at the start (and what’s reflected in the new command APIs): lowercase for HTML attributes names kebab-case for HTML attribute values camelCase for JS counterparts Let’s not even get into SVG attribute names We need one of those “bless this mess” signs that we can hang over the World Wide Web. Email · Mastodon · Bluesky
I’ve written previously about reloading a document using only HTML but that got me thinking: What are all the values you can put in an anchor tag’s href attribute? Well, I looked around. I found some things I already knew about, e.g. Link protocols like mailto:, tel:, sms: and javascript: which deal with specific ways of handling links. Protocol-relative links, e.g. href="//" Text fragments for linking to specific pieces of text on a page, e.g. href="#:~:text=foo" But I also found some things I didn’t know about (or only vaguely knew about) so I wrote them down in an attempt to remember them. href="#" Scrolls to the top of a document. I knew that. But I’m writing because #top will also scroll to the top if there isn’t another element with id="top" in the document. I didn’t know that. (Spec: “If decodedFragment is an ASCII case-insensitive match for the string top, then return the top of the document.”) href="" Reloads the current page, preserving the search string but removing the hash string (if present). URL href="" resolves to /path/ /path/ /path/#foo /path/ /path/?id=foo /path/?id=foo /path/?id=foo#bar /path/?id=foo href="." Reloads the current page, removing both the search and hash strings (if present). Note: If you’re using href="." as a link to the current page, ensure your URLs have a trailing slash or you may get surprising navigation behavior. The path is interpreted as a file, so "." resolves to the parent directory of the current location. URL href="." resolves to /path / /path#foo / /path?id=foo / /path/ /path/ /path/#foo /path/ /path/?id=foo /path/ /path/index.html /path/ href="?" Reloads the current page, removing both the search and hash strings (if present). However, it preserves the ? character. Note: Unlike href=".", trailing slashes don’t matter. The search parameters will be removed but the path will be preserved as-is. URL href="?" resolves to /path /path? /path#foo /path? /path?id=foo /path? /path?id=foo#bar /path? /index.html /index.html? href="data:" You can make links that navigate to data URLs. The super-readable version of this would be: <a href="data:text/plain,hello world"> View plain text data URL </a> But you probably want data: URLs to be encoded so you don’t get unexpected behavior, e.g. <a href="data:text/plain,hello%20world"> View plain text data URL </a> Go ahead and try it (FYI: may not work in your user agent). Here’s a plain-text file and an HTML file. href="video.mp4#t=10,20" Media fragments allow linking to specific parts of a media file, like audio or video. For example, video.mp4#t=10,20 links to a video. It starts play at 10 seconds, and stops it at 20 seconds. (Support is limited at the time of this writing.) See For Yourself I tested a lot of this stuff in the browser and via JS. I think I got all these right. Thanks to JavaScript’s URL constructor (and the ability to pass a base URL), I could programmatically explore how a lot of these href’s would resolve. Here’s a snippet of the test code I wrote. You can copy/paste this in your console and they should all pass 🤞 const assertions = [ // Preserves search string but strips hash // x -> { search: '?...', hash: '' } { href: '', location: '/path', resolves_to: '/path' }, { href: '', location: '/path/', resolves_to: '/path/' }, { href: '', location: '/path/#foo', resolves_to: '/path/' }, { href: '', location: '/path/?id=foo', resolves_to: '/path/?id=foo' }, { href: '', location: '/path/?id=foo#bar', resolves_to: '/path/?id=foo' }, // Strips search and hash strings // x -> { search: '', hash: '' } { href: '.', location: '/path', resolves_to: '/' }, { href: '.', location: `/path#foo`, resolves_to: `/` }, { href: '.', location: `/path?id=foo`, resolves_to: `/` }, { href: '.', location: `/path/`, resolves_to: `/path/` }, { href: '.', location: `/path/#foo`, resolves_to: `/path/` }, { href: '.', location: `/path/?id=foo`, resolves_to: `/path/` }, { href: '.', location: `/path/index.html`, resolves_to: `/path/` }, // Strips search parameters and hash string, // but preserves search delimeter (`?`) // x -> { search: '?', hash: '' } { href: '?', location: '/path', resolves_to: '/path?' }, { href: '?', location: '/path#foo', resolves_to: '/path?' }, { href: '?', location: '/path?id=foo', resolves_to: '/path?' }, { href: '?', location: '/path/', resolves_to: '/path/?' }, { href: '?', location: '/path/?id=foo#bar', resolves_to: '/path/?' }, { href: '?', location: '/index.html#foo', resolves_to: '/index.html?'} ]; const assertions_evaluated = assertions.map(({ href, location, resolves_to }) => { const domain = 'https://example.com'; const expected = new URL(href, domain + location).toString(); const received = new URL(domain + resolves_to).toString(); return { href, location, expected: expected.replace(domain, ''), received: received.replace(domain, ''), passed: expected === received }; }); console.table(assertions_evaluated); Email · Mastodon · Bluesky
After shipping my work transforming HTML with Netlify’s edge functions I realized I have a little bug: the order of the icons specified in the URL doesn’t match the order in which they are displayed on screen. Why’s this happening? I have a bunch of links in my HTML document, like this: <icon-list> <a href="/1/">…</a> <a href="/2/">…</a> <a href="/3/">…</a> <!-- 2000+ more --> </icon-list> I use html-rewriter in my edge function to strip out the HTML for icons not specified in the URL. So for a request to: /lookup?id=1&id=2 My HTML will be transformed like so: <icon-list> <!-- Parser keeps these two --> <a href="/1/">…</a> <a href="/2/">…</a> <!-- But removes this one --> <a href="/3/">…</a> </icon-list> Resulting in less HTML over the wire to the client. But what about the order of the IDs in the URL? What if the request is to: /lookup?id=2&id=1 Instead of: /lookup?id=1&id=2 In the source HTML document containing all the icons, they’re marked up in reverse chronological order. But the request for this page may specify a different order for icons in the URL. So how do I rewrite the HTML to match the URL’s ordering? The problem is that html-rewriter doesn’t give me a fully-parsed DOM to work with. I can’t do things like “move this node to the top” or “move this node to position x”. With html-rewriter, you only “see” each element as it streams past. Once it passes by, your chance at modifying it is gone. (It seems that’s just the way these edge function tools are designed to work, keeps them lean and performant and I can’t shoot myself in the foot). So how do I change the icon’s display order to match what’s in the URL if I can’t modify the order of the elements in the HTML? CSS to the rescue! Because my markup is just a bunch of <a> tags inside a custom element and I’m using CSS grid for layout, I can use the order property in CSS! All the IDs are in the URL, and their position as parameters has meaning, so I assign their ordering to each element as it passes by html-rewriter. Here’s some pseudo code: // Get all the IDs in the URL const ids = url.searchParams.getAll("id"); // Select all the icons in the HTML rewriter.on("icon-list a", { element: (element) => { // Get the ID const id = element.getAttribute('id'); // If it's in our list, set it's order // position from the URL if (ids.includes(id)) { const order = ids.indexOf(id); element.setAttribute( "style", `order: ${order}` ); // Otherwise, remove it } else { element.remove(); } }, }); Boom! I didn’t have to change the order in the source HTML document, but I can still get the displaying ordering to match what’s in the URL. I love shifty little workarounds like this! Email · Mastodon · Bluesky
More in programming
As with my last post on AI, let me open with a statement: Just because most people hold AI a certain way, doesn’t mean that we always must, either now or in the future. As I noted in that piece, and my shades of gray post, I am well aware — and agree with — … Continue reading Must we always use LLMs this way? →
TokyoDev has grown substantially over the past few years. We’ve expanded our community, dramatically increased the scope and frequency of our events, and have curated a library of articles for international developers. Despite all that, the way we run the business hasn’t changed much. I’ve continued to coordinate most of these activities myself, making the final decisions and keeping everything connected. In short, TokyoDev cannot run without my daily input. That approach worked well when TokyoDev was smaller, but it’s increasingly limiting how much we can accomplish. To help the business grow further, I wanted to find someone to take over some of my responsibilities and bring a fresh perspective. This is a significant step for me personally, as while I have worked with many contractors over the years, I have never actually hired a regular employee. Most importantly, I wanted to ensure that this person was someone I could trust to understand what TokyoDev stands for, and to make decisions in line with our philosophy. So I’m happy to announce that Scott Rothrock is joining TokyoDev full time as our Head of Operations. About Scott Scott has lived in Japan for nearly 20 years and has worked as a software engineer in multiple industries and environments, including small Japanese-owned businesses, overseas employers, and international companies based in Japan. Until the end of October 2026, he was the head of the Japan Markets team at Kraken Technologies, where he led an international team of software engineers in delivering complicated, regulated products on strict timelines for Japanese electricity and gas retailers, while also ensuring compliance with evolving organizational and global standards. He’s made a name for himself both inside and outside Japan as a kind, effective mentor who can cultivate great engineers and leaders. Scott’s previous role in TokyoDev Some of you may already know Scott in another capacity, as he has been involved with TokyoDev since 2022. He began as a community volunteer and later became our community manager, which also included responsibilities such as managing our article pipeline from submission to publishing. When I created TokyoDev’s Discord, I had no previous experience running an online community. Scott joined soon after I started and began helping other members, stepping in when people behaved inappropriately, and configuring our roles and permissions and safety features. I was impressed by his initiative and asked him to become an official moderator in January 2023. Outside of his role as a moderator, Scott has always pushed TokyoDev to grow; for example, he arranged internet events such as livestreamed AMAs and interviews. He organized TokyoDev’s first meetup as a volunteer in February 2023, which taught me that there was interest in TokyoDev events outside of the internet. By the end of 2023, I had brought him on as our part-time community manager. What I saw throughout his tenure was that Scott continued to take initiative in expanding TokyoDev. Scott was one of our first external contributors, writing about his experience living with a disability in Japan. He encouraged me to expand and refine both our editing and submission processes so that we could reach out to even more contributors and platform their perspectives. The editorial team now consists of him and Rebecca Callahan, and they’ve had a hand in every article that TokyoDev has published. In other words, since 2022, Scott has shown that he cares about TokyoDev as much as I do. He is invested in what we do and why we do it, and shares my vision for what TokyoDev can become. What changes now Scott’s experiences as an engineer, a mentor, and a leader make me confident that, as our Head of Operations, he will continue to help TokyoDev mature. A big part of what has made TokyoDev successful is that I see the software developers who use our site as my peers and genuinely want to help them. Scott shares that perspective, and will join me in ensuring that TokyoDev remains true to its principles while we grow. So what changes in the short term? Nothing dramatic. I will teach Scott about managing TokyoDev as a business, and he will document our processes and products as a part of that learning. He will also look for areas of improvement while ensuring that we remain compliant with regulations and labor law. Over time, I will hand over some other responsibilities. I will continue to run TokyoDev, but TokyoDev will become less dependent on me for its day-to-day operations. Long term, I’m excited about what this will enable us to do. TokyoDev has always been about helping international software developers build successful careers in Japan, and bringing Scott on full time puts us in a much better position to continue doing that. We look forward to writing the next chapter of TokyoDev together.
Kidz Fun Art is a drawing, colouring and animation app for kids that I’ve been building since 2021. It runs in the browser also as a simple wrapper app on iOS, iPadOS and Windows. It wasn’t getting a great click through rate on Google, even for people who directly searched for it. So, for two days I took a hard look at how fast it loads and how search engines see it. It wasn’t flattering. This post covers what I found, what I changed and what the graphs say now. Short version: on a simulated slow phone, the homepage’s Largest Contentful Paint got about 2.6× faster (15.9 s to 6.1 s) and its first load is about 82% smaller (4.2 MB to 0.75 MB). I also fixed a set of SEO mistakes that are, frankly, embarrassing to write down. I’ll write them down anyway. Part 1: Google had no idea what the site was for I started by reading 16 months of Google Search Console data. 9,380 clicks in total. About 9,200 came from people who had typed “kidz fun art” or a close spelling. People searching for what the app actually does (“coloring app for kids”, “ai art for kids”, “make a comic book”) sent the site 164 clicks. In 16 months. Total. When there was a relevant page, Google ranked it well. The site was #1 for things like “drawing app for kids ipad” and a German query that means “paint by numbers app without ads”. There just weren’t many relevant pages. Then I looked at the code, and the cause was obvious. The homepage <title> was “Kidz Fun Art” in all 12 languages. That’s a fine name, and a terrible title. It tells a search engine nothing. The homepage’s first <h1> was the pricing table’s “Choose your experience”. I was, in effect, telling Google that the most important thing on my homepage was the checkout. Every blog post had the same meta description: a generic line about “news, updates, tips”. Each post’s front matter already had a perfectly good excerpt field that nobody read. Blog posts had two <h1>s: the site header and the post title. There was no structured data at all. The sitemap that redirected every single URL This one stings. The sitemap is the one file whose whole job is to say “here are my URLs, please index them”. Mine listed 17 URLs, and every one of them redirected. The sitemap build used an environment variable that resolved to kidzfun.art. The site lives on www.kidzfun.art, so every URL got a 308. Only the English blog posts were listed. The other 11 languages appeared only as hreflang alternates, which pointed at redirecting URLs too. There were no <link rel="canonical"> tags on any page and no hreflang in the page <head>. Google was left to guess which URL was the real one, and it guessed wrong a lot. What I changed: The sitemap is now built on https://www.kidzfun.art, with 204 URLs: every home page, blog index, blog post, About page and gallery page, in all 12 languages. Each one lists all of its language alternates plus an x-default. A shared SeoLinks component adds an absolute canonical (www, no query string) and the full hreflang set to every public page. The ?v= cache-busting URLs that had been showing up as duplicates now canonicalise to the clean URL. /xx/blog/yy/... URLs, which returned a 500 in production (oops), now 308 to /blog/yy/.... Login, account, debug, export and embed pages send X-Robots-Tag: noindex, follow from next.config.js, so they stop using up crawl budget. robots.txt now mentions the sitemap. Novel idea. Why Google skipped half the site Search Console’s Pages report had 93 of 174 known pages not indexed. Every reason on that list traces back to the mistakes above: “Page with redirect” (22): that sitemap, plus internal links to the non-www host. “Duplicate without user-selected canonical” (18): I hadn’t selected any canonicals. Fair cop. “Crawled, currently not indexed” (39): mostly translated posts that Google reached through redirecting URLs, plus thin pages like /login. “Discovered, currently not indexed” (12): Google found these and decided they weren’t worth a visit. With no sitemap entry and no hreflang, I hadn’t given it a reason to. On-page fixes Titles and descriptions: Each blog post got its own seoTitle and description, in all 12 languages. The meta description now comes from the post’s excerpt, which is what that field was for all along. The About pages take their title and description from their own localized Markdown. They had been sharing an English title and a generic description. One <h1> per page: A # heading inside a post’s Markdown now renders as an <h2>, so the post title is the only <h1>. The About page opts back in with a keepH1 prop. Its Markdown heading is the page title. This fix arrived in two parts. The first part left the About page with zero <h1>s. I noticed, eventually. Structured data and social tags: JSON-LD for the home page (the app), blog posts (articles) and the embedded videos. Open Graph and X/Twitter tags on every public page, so shared links get a proper card. A real 404 for deleted gallery images: The AI gallery shows a friendly “AI Artwork Not Found” page when an image has been deleted. It used to return 200 OK, which Google calls a “soft 404” and dislikes. It now returns a 404 with noindex, and a 503 if the Firestore lookup itself fails, so a database hiccup tells crawlers “come back later” rather than “this is gone”. Part 2: Making the homepage fast The homepage is the app. It works offline, so every dialog (save, stickers, colouring pages, “get an adult”, “no wifi”) is server-rendered into the HTML up front. That’s a deliberate trade-off, and I kept it because I want new users to be able to immediately be able to start drawing as soon as they launch the app. What I hadn’t thought about was what it meant for the network. What the homepage downloaded before the app could start I measured the live site with a Lighthouse-style mobile profile: slow 4G (1.6 Mbps, 150 ms latency), 4× CPU slowdown, empty cache. First load: 4.5 MB over 198 requests. The homepage HTML alone was 358 KB, with about 77 <img> tags in hidden dialogs. The browser dutifully fetched every one of those images. The script that starts the app (main.min.js, 191 KB) sat at the very end of the document, so the browser found it last and gave it whatever bandwidth was left. The app script finished arriving at about 14 seconds. The CPU was not the problem. Every long task was under 300 ms. This was purely about bandwidth and request order. I had built a very polite queue and put my own app at the back of it. Watch the queue The waterfall is a simplified illustration. The milestone times (first paint, LCP, load) are measured: slow 4G + 4× CPU, local production build, median of 3 runs. My Largest Contentful Paint was the “Contact support” link The canvas doesn’t count toward LCP, and the toolbar buttons are small. So on a slow load the largest thing painted was… the loading dialog. The loading dialog fades in its “Taking a while? Contact support” text after 5 to 7.5 seconds. On a slow connection, that text became the page’s LCP element, at 15.9 s. I was measuring my page speed by how long it took to suggest the user complain about my page speed. There’s a lesson in there somewhere. The fix wasn’t to change the dialog. It was to make the app start sooner, so it paints before that text ever appears. What I changed Preload the app script. I added <link rel="preload" as="script"> in <head> for main.min.js and errorHandler.min.js. The <script> tags stay where they were, so execution order doesn’t change. The browser just starts fetching them before any image. This one line did more than anything else on this list. It’s a little humbling. Turn the three dialog GIFs into MP4s. Three animated GIFs: an arrow pushing pictures into a tablet (927 KB), a dancing rainbow pencil (650 KB) and a paper plane (305 KB). That’s 1.9 MB of decoration in dialogs most visitors never open on their first visit. I re-encoded them with ffmpeg: H.264 High profile, -preset veryslow -crf 20, yuv420p, +faststart, constant frame rate taken from each GIF’s frame delay. The commands are committed as scripts/gif-to-mp4.sh. The result is 130 KB in total, with SSIM between 0.988 and 0.993 against the originals. The pencil needed tpad=stop_mode=clone:stop_duration=0.2, because ffmpeg’s GIF reader drops the final 250 ms hold and the dance lost its big finish. The new <video autoplay loop muted playsinline> tags render at exactly the same size and class as the old <img> tags. Alt text moved to aria-label. Locked colouring thumbnails were full-size PNGs. In the colouring page picker, locked pages used the full-size colouring PNG as their background image, inlined into the HTML. That came to about 1.3 MB on every first visit, to draw thumbnails in a dialog that was closed. They now use the small image, set when the picker opens, like the unlocked ones always did. Sticker thumbnails wait their turn. I tried loading="lazy" first. It didn’t help: Chrome fetched the images before the stylesheet that hides the dialogs had arrived, so as far as it knew they were visible. Sticker thumbnails and the media library’s YouTube thumbnail now use data-deferred-src. They load 3 seconds after the load event, or as soon as their dialog opens, whichever comes first. The service worker preload starts after load. The offline preload queue (about 2 MB of colouring pages and stickers) used to start while the page was still loading and compete with it. Now it starts after the load event. Same files, same offline result, no fighting for bandwidth. Analytics is async. Nothing waited for it, so nothing needed to block on it. Cache headers. /images/*: max-age=86400, stale-while-revalidate=604800. It had been max-age=0, so every image was re-checked on every visit. Versioned /js, /css and /addToHomescreen files are immutable for a year in production. Offline still has to work Offline support is a core feature, so “just don’t download it” was never an option. Some of the changes above put it at risk, and a couple of things turned up along the way: Safari plays video from byte ranges. Safari requests video with Range: bytes=.... Answer that with a full cached response and the video won’t play. The service worker now answers Range requests from its cache with a proper 206 Partial Content slice (lib/util/rangeResponse.ts, with unit tests). First-visit gap: on a first visit the service worker isn’t controlling the page yet, so dialog images only reached the offline cache on the second online visit. The page’s own dialog images and videos now go to the front of the offline preload queue on the first visit. I nearly downloaded my whole site, 12 times over. The service worker cached every <link href> it found in the page. The new SEO work had just added canonical and hreflang <link>s pointing at all 12 localized homepages. So every new visitor would have downloaded about 12 extra homepages, in languages they don’t speak, “for offline use”. I caught it before production. The service worker now skips rel=canonical and rel=alternate. Safari stopped the service worker mid-download. The old preload queue ran on timers after the request had been answered. Safari considers an idle service worker fair game, so it stopped it after the first few images. The page now sends images in batches of 10, and the service worker caches each batch before it replies. A page lock-up I’d never noticed. resizeDialog added a new “image loaded” listener every time the window resized. With lots of images loading at once, the listeners multiplied until the page locked up. It now attaches one listener per image, which, in hindsight, is how many it needed. Part 3: The blog Blog index cards used the full 1920 px screenshots as covers, up to 500 KB each, in a box about 200 px wide. Each card was a little billboard, shrunk down by the browser on every visit. Covers now go through next/image with sizes that match the actual card widths, so the browser gets a resized WebP. The first few cards get priority. The rest load lazily. The first sizes hint was too small at some widths and made covers blurry. It now matches the real card widths, up to about 630 px between 769 px and 1028 px wide. Post pages: The cover image gets fetchpriority="high", and images further down the post load lazily. Five images were recompressed in place, keeping the same filenames and dimensions. The PNGs came out about 4× smaller and the JPEGs about 40% smaller. I deleted a 1.1 MB cover.png that nothing referenced. All 12 translations of that post used cover.jpg. The PNG had just been sitting in public/ taking up space. Results on the slow 4G profile: /blog LCP went from 13.3 s to 1.8 s. A typical post went from 3.9 s to 1.7 s. The gallery didn’t get faster, on purpose. It got a 5-minute edge cache and a cached Firestore image count, which fixed its slow server responses. I decided not to change its 20 full-size PNG thumbnails, so its lab LCP barely moved (8.4 s to 8.6 s). That’s a choice, and the chart owns it. Part 4: Lighthouse homework After the speed work went live I ran Lighthouse on the production homepage (mobile) and cleaned up what it flagged. Performance stayed in the low 70s, so I have some more work to do, but it’s moved nicely in the right direction. Part 5: Telling the search engines Fixing the site is half the job. The other half is getting crawlers to come back and notice. Google Search Console: Resubmitted the www sitemap. Clicked “Validate fix” on “Duplicate without user-selected canonical” and on the redirect errors. Requested indexing for the main language homepages and the top blog posts. The quota is about 10 a day, so it’ll take a few days. Wrote down a baseline from the Performance report, so in 4 to 8 weeks I can tell whether any of this worked. Bing Webmaster Tools: Submitted all 204 sitemap URLs through URL Submission. The daily quota is 10,000, so no trickle-feeding needed. Bing’s index also feeds DuckDuckGo and several AI search tools, so it’s cheap extra reach. Most of Bing’s “SEO recommendations” pointed at old ?v= URLs and old titles. They’ll clear as Bing recrawls. What I’m not watching: the Lighthouse score. Google ranks on real-user Chrome data (the Chrome UX Report): a rolling 28-day window, judged at the 75th percentile. So the honest answer to “did it work?” is “ask me in a month”. How I kept from breaking things The app has hundreds of unit and integration tests, all of which still pass (even though they do take over 30 minutes to run). I also manually regression tested all the riskiest changes. Hopefully I don’t make things worse before they get better… Lessons, mostly at my own expense Read your own sitemap. Actually open it and click a URL. Mine had been quietly redirecting for who knows how long. <link rel="preload"> for the script that boots your app is the cheapest big win there is. Browsers fetch resources in the order they find them. If your app script is at the bottom of a 358 KB document full of images, it really is last in line. Check what your LCP element actually is before you try to make it faster. Mine was a “Contact support” link. GIF is an image format from 1987 that I was using as a video format. A real video codec beats it by an order of magnitude at the same quality. try/catch doesn’t catch promise rejections. I knew that. My code didn’t. Every <link> you add to <head> is something your service worker might decide to download. Speed scores are for diagnosis. Rankings come from real users. Fix what the lab finds, then wait for the field data. Epilogue You’re still here? Wow. Cool. After all this, I’m hoping that users notice nothing other than quicker app start times. I’m looking forward to keeping an eye on traffic and retention in the coming weeks. Wish me luck!
Five months ago, we rebuilt our warehouse on DuckDB instead of ClickHouse. We did it because a shared ClickHouse cluster couldn't handle hours-long…
