Making API Documentation Dynamic
How to unlock API documentation interactivity.
Documentation can kill an API. It's the most important thing influencing its quality. It's the very first thing consumers interact with. If the documentation is low quality, consumers will assume the API itself is low quality. Your job as the API owner is to make sure your documentation offers the best possible developer experience. And that also means replacing or removing anything that introduces unwanted friction. Especially in areas that involve interactivity or personalization. There, having just static text isn't enough. You need to add dynamic elements to the mix. But how exactly do you do that? How do you migrate from static Markdown to a place where you can use dynamic elements? Keep reading to get all the details.
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Markdown is not enough. At least, not if what you want is to offer interactivity or personalization. However, the existing reality of technical writing is built almost entirely on Markdown. Collectively, we have adopted a technology from 2004 as the way to format all kinds of content, both on and offline. We’re even using it to give instructions to AI agents. That’s how versatile Markdown is. From a writing perspective, it doesn’t get much easier. It’s simple to write, easy to read, and machines can understand it very well. What’s not to like about it, then? Well, one thing it misses is the lack of ability to define interactive elements. Or, elements that change their values based on some condition. These are exactly the two things consumers prefer when accessing API documentation. Consumers want to be able to try an API operation and access concrete example information, or configuration data, such as credentials. Markdown alone isn’t going to provide these elements for you. Fortunately, there’s something else that will, as we’ll see next.
The solution you need is called MDX. It’s a superset of Markdown that lets you embed components within your content. Or just render dynamic information obtained from executing JavaScript. You get to keep the simplicity and versatility of Markdown. But now, you can also use dynamic elements and data. This completely changes the game for API documentation. You can, for instance, embed a component to show the consumer’s API key, or one to make an API request and show its response. This hands-on interactivity helps users test the API faster. And, because of that, it significantly reduces the Time to First Call, or TTFC. Since a low TTFC means the API onboarding experience is excellent, it translates directly into a higher perception of quality. Which is exactly what you’re looking for.
Moving from pure Markdown to MDX doesn’t have to be complicated. However, and especially if you have little coding experience, putting an MDX system together from scratch can be challenging. Luckily, there are many systems that already support MDX. Docusaurus, for instance, supports it by default. Astro is another example of a content system where you can use MDX. There are more options, including commercial ones. What I’d recommend, though, is to check out the official documentation and have a go at the MDX playground. It’s an easy-to-use sandbox where you can experiment and quickly see how things work. Here’s what a simple MDX document that you can try there would look like:
export const daysValid = 30
export const expiryDate = new Date(Date.now() + daysValid * 24 * 60 * 60 * 1000).toLocaleDateString()
If you generated an API key today, it would be valid until **{expiryDate}**.Can you guess what id does? It calculates the expiry date of an API key. The first line sets the validity to 30 days. Then, the second line calculates the expiry date for an API key generated today. Take it for a spin at the MDX playground and see that it would render to something like this, depending on your current date and locale:
If you generated an API key today, it would be valid until 4/5/2026.
Easy, right? In principle, it’s simple to use and easy to understand. Let’s look at another example:
export const environment = 'production'
export const baseUrl = environment === 'production' ? 'api.acme.com' : 'staging-api.acme.com'
Your base URL for this project is: <code>{baseUrl}</code>.What does it do? Try changing the value of the environment variable from production to staging and see how that affects the output:
Your base URL for this project is:
staging-api.acme.com.
The goal of these two examples is just to illustrate what you can do. You can use more sophisticated JavaScript expressions, functions, and even import external code, though. There’s a lot of power to be unfolded with something that looks quite simple.
However, this solution also has its disadvantages. There is a clear cost to implementing MDX, as opposed to hosting and rendering pure Markdown. You can drop a simple README.md file in a code repository and be done. A README acts as the front door to an API and offers consumers brief information to get started. You can use basic static site generators to turn pure Markdown into HTML with almost zero overhead. But MDX is different because it relies on a build step. You can’t just host the documentation statically without running it through a compiler first. No, you also have to manage and maintain the components that you plan to use. Your documentation team now needs to understand JSX and how to import components and handle variables. If I were you, I’d carefully weigh this added complexity against all the benefits that MDX offers.
At this point, you have all the information you need to make your decision. You know that documentation is the most important factor in influencing the quality of your API. You understand that pure Markdown is simple to maintain but fundamentally static. You see that MDX offers a way to inject components directly into your writing. That alone can drastically improve the onboarding experience and lower the TTFC. But you also recognize the technical overhead of managing dynamic documentation. If you have a very simple API with limited resources, a well-written Markdown README might be enough. On the other hand, if you want to offer a premium and interactive experience, MDX is the clear winner. Let’s not debate more. The ultimate judge of quality is the consumer. That’s why I’d choose the tool that helps users get the job done right the first time. What would you do?