By “dynamic” social media cards, I mean cards for pages of user-generated content or something like an e-commerce site with loads of different products. Meaning too many pages to reasonably design a custom graphic by hand for each. So what we’re talking about here is a system to generate dynamic images with dynamic data.
If you can custom design a social media card image, you probably should. Make it branded, enticing, and quickly communicate the most important thing about what’s going on at that URL.
GitHub is a good example of dynamically generated social media cards. Each repo has a generated image like this:
That’s an image, not a screenshot I took, but one they dynamically created.
A typical implementation makes that show up with meta tags in the HTML response like this:
<meta property="og:image" content="https://example.com/images/social/1.jpg">
<meta name="twitter:image" content="https://example.com/images/social/1.jpg">
<meta name="twitter:card" content="summary_large_image">Code language: HTML, XML (xml)There are more possible tags (see the Open Graph protocol), plus variations and platform-specific stuff, naturally. Plus, typically a site will have other tags that ultimately help with social sharing, SEO, and general UX, like:
<title>Raccoon Animation</title>
<meta name="description" content="A cool demo of a raccoon in roller skates.">
<link rel="icon" type="image/x-icon" href="/assets/favicon.ico" />Code language: HTML, XML (xml)An example of a more “complete” set of HTML:
<title>Balatro Planet Card Scaling</title>
<meta name="description" content="A code demo by Chris Coyier created on CodePen">
<link rel="icon" type="image/x-icon" href="/assets/favicon.ico" />
<meta property="og:title" content="Balatro Planet Card Scaling"><meta property="og:description" content="Interactive Example of the +Mult and +Chips scaling of Planet Cards in the game Balatro">
<meta property="og:url" content="https://codepen.io/editor/chriscoyier/pen/01a14173-dbcb-7828-afc4-9a8907157ecb">
<meta property="og:site_name" content="CodePen">
<meta property="og:image" content="https://codepen.io/screenshots/xxx/1280.jpg">
<meta property="og:image:width" content="1280">
<meta property="og:image:height" content="720">
<meta name="twitter:card" content="summary_large_image">
<meta name="twitter:site" content="@CodePen">
<meta name="twitter:creator" content="Chris Coyier ">
<meta name="twitter:title" content="Balatro Planet Card Scaling">
<meta name="twitter:description" content="Interactive Example of the +Mult and +Chips scaling of Planet Cards in the game Balatro">
<meta name="twitter:image" content="https://codepen.io/screenshots/xxx/1280.jpg">Code language: HTML, XML (xml)I’m pretty sure you still use the twitter:foo meta tags for X, if you care to. The “X” docs have no guidance on this. Should they just support og:foo style tags? Yes. Do they? I don’t think so, but please correct me if I’m wrong.
Also weird: I used GitHub as an example above, but many of the meta/og tags don’t appear in the GitHub HTML source when you view a repo, so they must do something extra exotic to make it happen. 🤷♀️
With those tags in place, supporting platforms will show special extra content. For example, if I text this repo to someone over iMessage, this is what they see:
This is referred to as unfurling. How a link unfurls.
What actually unfurls in any given app can change at any time; you aren’t guaranteed any control over it, and it depends on user preferences. For instance, in Slack, you can tell it to never unfurl for particular domains.
You can also add alt text for social meta images, which is probably a good idea if you can properly describe it.
<meta property="og:image" content="https://example.com/images/og/abc123.png">
<meta property="og:image:alt" content="A rounded purple-to-pink gradient button labeled 'Get Started' on a dark background, with a code editor preview beside it.">Code language: HTML, XML (xml)Example Unfurls
Here’s a bunch of examples of apps and how they unfurl, mostly using Pens from CodePen as that’s what I’m actively thinking about. Each has differences and notes worth considering. I’m listing next to each of them what they have and don’t have.
- They aren’t judgment calls; it’s just an inventory of what is there.
- I’m not talking about what might be in the image (that’s what we’re trying to figure out) — just if it has an image and the prominence.
Discord
- ✅ URL Visible
- ✅ Site Title
- ❌ Site URL
- ❌ Site Favicon
- ✅ Page Title
- ✅ Page Description
- ✅ Large Image
Notes: Only one that doesn’t truncate the URL?
Mastodon
- ☯️ URL Visible (truncated)
- ✅ Site Title
- ❌ Site URL
- ❌ Site Favicon
- ✅ Page Title
- ✅ Page Description
- ✅ Large Image
The Elk client for Mastodon does things differently.
No idea why the image is mini and broken.
Slack
- ☯️ URL Visible (truncated)
- ✅ Site Title
- ❌ Site URL
- ✅ Site Favicon
- ✅ Page Title
- ✅ Page Description
- ❌ Large Image (small and cropped to a square)
Bluesky
- ✅ URL Visible (truncated)
- ❌ Site Title
- ✅ Site URL
- ❌ Site Favicon
- ✅ Page Title
- ✅ Page Description
- ✅ Large Image (kinda huge actually)
iMessage
- ❌ URL Visible (replaces it entirely with unfurl)
- ❌ Site Title
- ✅ Site URL
- ❌ Site Favicon
- ✅ Page Title
- ❌ Page Description
- ✅ Large Image
- ❌ URL Visible (might be behind “more” and obfuscated)
- ❌ Site Title
- ✅ Site URL
- ❌ Site Favicon
- ✅ Page Title
- ❌ Page Description
- ❌ Large Image (small but not cropped)
Threads
- ✅ URL Visible (truncated)
- ❌ Site Title
- ✅ Site URL
- ✅ Site Favicon
- ✅ Page Title
- ❌ Page Description
- ✅ Large Image
- ✅ URL Visible
- ❌ Site Title
- ✅ Site URL
- ✅ Site Favicon
- ✅ Page Title
- ✅ Page Description
- ✅ Large Image
X
- ❌ URL Visible
- ✅ Site Title
- ❌ Site URL
- ❌ Site Favicon
- ✅ Page Title (overlays image)
- ✅ Page Description
- ✅ Large Image
Other Sites That Unfurl
This isn’t a complete list of sites that unfurl, it’s just a bunch of common ones. There’s also Facebook, Signal, Telegram, etc. I’m sure you can think of a bunch. If this matters a lot to you, it’s probably worth testing on all of them.
So… What Should a Large Image Actually Contain?
Should you show the item title?
Maybe not! This seems to be the thing that almost every unfurling has anyway. So listing it again almost seems unnecessarily duplicative.
And yet! It seems to be the most common thing that custom cards duplicate. My first-ever take on this on CSS-Tricks back in the day duplicated the title for sure:
I admit it does make the title super noticeable, and typography can be a big part of a site’s brand. Smashing Mag does it and you certainly get a taste of their style.
This site has opted not to include the post title on the card. Instead, it uses a custom graphic for each post (not always scalable), but still builds the card dynamically with the branded bar across the bottom.
One tool for building dynamic cards is WordPress’ Jetpack Social plugin. It’s a very basic implementation, though, which just sets the post title on top of whatever “custom post image” you select for the post, with a gradient on top to make the text more visible.
Personally, I lean toward not including the title, as it’s typically already there, and using the space for other things or just breathing room.
Should you show the site’s branding?
First, here is the site name and site URL. Unfurls tend to show one or the other. It looks like it’s trending toward showing the site URL. I imagine that’s a security thing. Any ol’ site could put “Facebook” as the <title>Facebook</title> which would make an unfurl look like it’s from Facebook on sites that list titles, whereas you can’t fake unfurls that list the actual URL like facebook.com or codepen.io or whatever. I kinda like seeing the URL myself.
It’s common enough that I’d lean toward not needing to include the site name or URL in the image itself.
Then there is the site’s favicon that shows in some unfurls, which is likely some form of the site’s logo. That’s less common to see in an unfurl, and if it’s there, it’s likely quite small.
I think the site’s logo is a decent candidate for putting in the custom image. That can make it unmistakably part of the site, which is kind of the point of branding.
Branding is a much bigger concept than just a logo, though. It’s typography, colors, the voice, the whole vibe of the thing. You could be like Zach and put your own mug on your personal blog’s social card:
Should you show the item’s URL?
Nah, probably not. Typically, sites unfurl in addition to showing the posted URL. The shown URL might be truncated, but it’ll follow the platform’s standard handling, and users will be used to it. So unless showing the complete URL is somehow super interesting and relevant, probably skip it.
Should you show the item’s description?
Again, a ton of unfurls show this already, so it’s probably equally as skippable as the title is. Only perhaps more so because it tends to be hierarchically less important than the title and more text, which is hard to fit in.
A full paragraph of text is unlikely to work in a social media card. If you know it’s fairly short, truncation is practical, and if it’s super interesting, I could see it working; otherwise, skip it. GitHub repo descriptions are usually decently short and fit the other criteria above, so I can see why they do it, even if it is relatively duplicative.
I could also see turning the hierarchy on its head. Maybe the description is the most interesting part of a dynamic page. Maybe a blog post with a custom excerpt could be an interesting take!
What kind of other dynamic data can you show?
This is where it gets interesting to me. Not to over-analyze the GitHub image over and over, but their choice to show off interesting GitHub-specific data is smart, I think.
If you’re looking at doing this, what kind of unique, interesting data do you have for that page? Likes/hearts? Analytics data? Number of reviews? Star rating? A sparkline? A price or discount?
Since I’m thinking about this in terms of CodePen, I’m wondering whether we could/should show hearts, views, and comments in the image. That might be cool, but if the numbers are low or zero… maybe not. But that’s the beauty of doing things dynamically: you could include information only when it’s actually interesting. Like a “Picked Pen” could say that, but say nothing when it isn’t.
Here are some ideas of what dynamic data could be:
- Author / Username
- User Avatar
- Analytic data, like “likes” and “views”
- A chart for something like a stock
- A waveform for something like a song
- An average customer rating for something like a product
- A discount for something like a SaaS plan
Just let the item speak for itself?
For example, games on Steam already have custom images, so the unfurl just uses that image, and that’s it.
That works perfectly well. I think it’s a good fit for Steam, and game developers are already particularly strongly incentivized to produce good and enticing images for the Steam website itself, and for this exact scenario.
What we already do on CodePen is take a screenshot of the Pen (on every save!) so we already have that to work with. For over a decade, that’s what we’ve used as the social image card already, letting the Pen speak for itself. It’s reasonable to leave it that way. But I think it’s also reasonable to bring a little bit more branding to the images and offer little bits of more interesting information. Not sure if we will, but we might!
Sometimes images are just really small
Generally, we’re talking about a 1200×630 image shown decently large. But most mobile screens aren’t that big, so readable text is iffy to begin with.
Platform Specific Stuff
You can’t truly control how platforms are going to unfurl. Things change over time, and different platforms do different things as times change. Twitter, as far as I recall, didn’t do “overlay” information like X does now, and who knows when that will change again. X is one of the rare sites that replaces the link in your post with the unfurl, making the unfurl pretty important as it’s the main thing a user can click.
Bluesky incorporates the standard.site schema, and when done correctly, you get a special “View Publication” button. It links to the site itself, not the article, which is a little weird, but it can at least draw a little extra attention and maybe some clicks.
On Slack, an admin user might remove an unfurl, then click an additional option to forever stop unfurling for that particular domain, meaning you can’t count on it at all.
YouTube is in a class of its own. It’s so popular that many platforms have their own special way of unfurling it, so the “card” is an embedded video. I doubt even YouTube itself has much control over this.
Interesting Technology for Dynamic Social Images
- Next.js has a whole built-in system for making them.
- Many other site-builder tools have custom plugins for it, like 11ty and WordPress.
- Cloudinary can build dynamic images through URL parameters alone.
So… what should you put on a dynamic custom social media card image?
- Whatever the most interesting thing you can show about the page is. Probably an actual image.
- Data that is contextual and relevant to the page. Particularly when it’s not available in the title, description, or any other meta tag.
- Not too much text. It’s probably duplicative anyway.
- Not too much, period!
