felix-arntz.me

Category: WordPress

  • Speculative Loading, or A Brief History of Landing a Performance Feature in WordPress Core

    Speculative Loading, or A Brief History of Landing a Performance Feature in WordPress Core

    Two years ago today, on May 22, 2023, I opened an experimental pull request for a new module in the Performance Lab plugin. That little experiment was the very first step on a long road that ultimately led to the “Speculative Loading” feature landing in WordPress 6.8 last month (April 2025).

    For those unfamiliar, the Speculative Loading feature enhances performance by speculatively loading pages a user is likely to visit next, which can make navigation feel almost instantaneous. If you want to dive into the technical nitty-gritty, I recommend checking out the “dev note” post on Make WordPress Core.

    This post, however, isn’t about the what or how of the feature itself. Instead, I want to pull back the curtain and share the story behind the feature—the milestones, the discussions, and the collaborative effort that took it from a spark of an idea to a reality for millions of WordPress sites. The impact is considerable even for the entire web. Keep reading to the end for concrete numbers. 👇

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  • Deploying Your WordPress Plugin’s “Tested Up To” Version Bump in Isolation

    Deploying Your WordPress Plugin’s “Tested Up To” Version Bump in Isolation

    Keeping the “Tested Up To” version of your WordPress plugin up-to-date on WordPress.org is crucial for ensuring compatibility and giving your users confidence. However, the process of manually updating this information can be a bit tedious, often involving a new release even if no other code changes are necessary.

    While there are existing GitHub Actions that can deploy plugin assets to WordPress.org, such as the excellent 10up/action-wordpress-plugin-asset-update, using them solely for updating the “Tested Up To” version without any customization can be less than ideal. You might inadvertently deploy other changes you’ve made to your readme.txt file or other assets, even if those weren’t intended for immediate release. This could lead to unexpected updates on the plugin directory.

    Imagine you implemented a new plugin feature in your GitHub repository which is not released yet, and you’ve already included documentation about it in the readme.txt. You wouldn’t want that to be deployed by accident when all you want to do is bump the “Tested Up To” version.

    This post highlights a targeted GitHub workflow for exactly this purpose, which allows you to automate the deployment of bumping your WordPress plugin’s “Tested Up To” version in isolation.

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  • Writing a WordPress plugin to generate image alt text with AI Services

    Writing a WordPress plugin to generate image alt text with AI Services

    In my initial post that announced the AI Services plugin for WordPress I mentioned several times how it simplifies using AI in WordPress by providing AI service abstractions as central infrastructure.

    In this post, let’s take a more hands-on look how you as a developer can use the AI Services plugin: We will write a WordPress plugin that generates alternative text for images in the block editor – a crucial aspect of good accessibility, which AI can be quite helpful with. Since the feature will be built on top of the AI Services plugin, it will work with Anthropic, Google, OpenAI – or any other AI service that you may want to use. And the entire plugin will consist of less than 200 lines of code – most of which will in fact be for the plugin’s UI.

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  • Introducing the AI Services plugin for WordPress

    Introducing the AI Services plugin for WordPress

    It’s safe to say the topic of generative AI doesn’t need an introduction in today’s age. It has been emerging throughout the tech world. However its adoption in the WordPress ecosystem has been slower than in other ecosystems. This is for various, mostly technical reasons that make implementing generative AI features in WordPress harder than elsewhere.

    That’s what I’m trying to address with AI Services, a new free open-source plugin that is now available for early access on GitHub, and as an early version 0.1.0 in the WordPress plugin directory.

    AI Services is an infrastructure plugin which makes AI centrally available in WordPress, whether via PHP, REST API, JavaScript, or WP-CLI – for any provider. Other plugins can make use of the APIs from the AI Services plugin to easily add AI capabilities to their own plugins, for whichever third party service they prefer: Whether it’s Anthropic, Google, or OpenAI, whether you’d like to use another service, or whether you’d like to leave the choice up to the end users of your plugin – AI Services makes it possible by providing access to the various APIs in a uniform way. It acts as a central hub for integrating AI services, allowing plugin developers to focus on functionality instead of managing individual service integrations. As an end user of WordPress, that means you have more control on how you would like to use the AI capabilities provided by the plugins.

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  • Autoloading WordPress options efficiently and responsibly

    Autoloading WordPress options efficiently and responsibly

    If you’re a WordPress plugin developer, you may have come across the concept of autoloading options. Or you may not, since knowing about autoloading options is, technically speaking, entirely optional when implementing a WordPress plugin that uses options. However, being unaware of the concept of autoloading options can lead to massive performance problems for large WordPress sites. It can notably slow down the server response of sites using your plugin. And by doing that, it hurts their “Time to First Byte” (TTFB), which directly contributes to the Core Web Vitals metric “Largest Contentful Paint” (LCP).

    This post is about explaining what autoloading options in WordPress is, how it works, and how plugins should go about it. We’ll go over the basics as well as explore how to use more recently introduced WordPress Core enhancements, including some code examples. This will hopefully help you get to a comprehensive understanding of how to apply autoloading in your WordPress plugins in a way that’s both efficient (for your own plugin’s usage) and responsible (for the overall sites using your plugin, in a gazillion of combinations with other plugins).

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  • My WordPress Core Contribution Workflow

    My WordPress Core Contribution Workflow

    During an informal meetup between the WordPress Core committers attending WordCamp US 2024, one of the topics we discussed was how each of us was handling commits. Given that WordPress Core uses svn and Trac for its source of truth but git and GitHub are encouraged for contributing, it can be a bit of a hassle to synchronize changes when it comes to committing code to WordPress Core.

    Fortunately, this is only relevant for the folks that commit code, i.e. nothing that a new contributor needs to worry about. Yet, there’s a good number of committers, and new ones are added regularly, so we thought it would be good to document our workflows. There’s no “official” documentation about this, simply because there’s no universally recommended approach. Many committers have come up with their own solutions throughout the years, so we decided it would be a great idea if each committer documented their approach, so that we would have a number of solutions to compare and for newer committers to review and choose from.

    This brief article outlines my personal workflow for committing to WordPress Core.

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  • An issue with block editor e2e test cross-version compatibility

    An issue with block editor e2e test cross-version compatibility

    While I was making minor updates to my Attachment Taxonomies plugin (GitHub repository) the other day, I noticed that the e2e tests were failing when run against WordPress version 6.1. Since the plugin’s minimum requirement is that version, I still run tests against it, to make sure it keeps working as expected.

    After some investigation, I noticed the issue was happening due to the way the block editor used to work prior to WordPress 6.3, when it started to be iframed by default. So the failure most likely wasn’t happening due to an actual bug in the plugin, but due to an issue with the e2e tests.

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  • Measuring website performance using WebPageTest (with WordPress 6.2)

    Measuring website performance using WebPageTest (with WordPress 6.2)

    In my post from last month, I am sharing my experience from rebuilding my WordPress website using a block theme, including a performance comparison. As part of that post, I included a spreadsheet with a detailed performance breakdown from before and after the changes. I only provided a bit of context for how I conducted the performance comparison in that post, however as promised, in this post I am sharing the concrete methodology that I used and how you can use it to measure performance of websites yourself.

    In order to better explain the methodology, I thought I might just do another similar kind of analysis that I would go over in this post. Last week, WordPress 6.2 was released, so no better opportunity than to measure how updating my website from WordPress 6.1 to 6.2 affects its performance!

    I created a spreadsheet with the full data for this new analysis, and in this post we’ll go over the process for how I got that data in detail.

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  • Rebuilding my website using a block theme

    Rebuilding my website using a block theme

    It’s been a while since I have posted on my blog. In fact almost 2 years now. But it’s been even longer since I have significantly touched the foundation of my website; other than the regular updates, adding a small plugin here or there, my website had been using the same infrastructure and theme since 2019. A lot of it even already existed the same way in 2018. My website had gotten really out of date, in terms of both content and technology. Some of the blocks I had implemented years ago were no longer working, so part of me was even afraid to open the block editor.

    A few weeks ago, I finally decided to change that and modernize my website. But it didn’t just came out of nowhere. Specifically, I wanted to update my website to use a block theme. I had been excited about them since they were in the exploration stage already in 2019, pretty much as far back as when I was rebuilding my website, “the old way”. The opportunities for enhancing performance due to the new block theme paradigm seemed extremely promising to me.

    Now that we’ve already had 3 major WordPress releases to establish and refine the new infrastructure, I decided to really give it a try. In this post I’ll share my experiences with you as well as the outcome and how it is impacting performance.

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  • Sharing content from your device directly into a new WordPress post

    Sharing content from your device directly into a new WordPress post

    It is tempting to rely on closed platforms and their native apps: They integrate well with your device’s capabilities and offer easy-to-use features for improved social engagement with your audience – however at the cost of locking you into their proprietary infrastructure and owning your content.

    But the open web has been catching up: A myriad of capabilities has been made available in the past few years through new standardized browser APIs which enable you and your audience to leverage the modern features they expect while remaining decentralized and under your control. To name a few:

    • Add to Home screen: You and your audience can add your website to their device’s home screen so that it shows up there with an icon, the same way they can install a native app, but without all the extra implications of that installation. Enable Add to Home screen in WordPress
    • Offline browsing: No longer will you see your browser’s ugly “Offline” page when losing the network connection, but you remain within the website’s / web app’s UI and can keep browsing content that was previously downloaded. Get offline browsing in WordPress
    • Engaging and replying to content from other websites: What closed social networks have been offering for seemingly ages has now finally come to the open web as well – with the difference that the data remains under your authority. Use webmentions in WordPress
    • Sharing content from your website: You can share content from your website to any other application, relying on your device’s integrated sharing UI – with the extra benefit of not requiring privacy-invasive sharing scripts from other platforms for it. Share content in WordPress

    Another capability which you are probably used to from native apps is sharing content from one app to another. While the last bullet point above covers sharing content from your website (via the Web Share API), it is now also possible to share content to your website (via the Web Share Target API) in the same integrated way, which is what we’re gonna focus on in this post.

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