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Making sense of atomic design: molecules and organisms

Our Interaction Designer, Alla Kholmatova, reflects on some of the aspects of using atomic design at FutureLearn.

An atomic design workshop

A year ago we wrote about building our first pattern library at FutureLearn and why we decided to use atomic design methodology. Overall, atomic design has worked out well for our team. It has helped us to build a shared understanding of the interface, make a transition towards a more modular system, and evolve our design language.

While some concepts in atomic design were clear from the start, others felt a bit foggy. For example, one area that we’re still trying to improve our understanding of, is the difference between molecules and organisms.

Molecules and organisms

Brad Frost defines molecules as “groups of atoms bonded together, the smallest fundamental units of a compound”, and organisms as “groups of molecules joined together to form a relatively complex, distinct section of an interface”.

While these definitions may sound simple in theory, we’ve been struggling to understand exactly when a molecule is complex enough to become an organism, the defining difference between the two types, and even why we need both types in the first place. (The CSS part of organisms and molecules are quite similar, wouldn’t it be simpler to just have smaller and larger molecules?)

Why have both types in the first place?

We felt that a separation between molecules and organisms brings (or could potentially bring) three main advantages.

  1. From the front-end perspective, organisms are good candidates for separating their HTML parts into partials (molecules are probably too simple for this).
  2. From the design perspective, it helps to understand the design, and see what parts it consists of. It also helps to find the right element quicker to use in your design (for example, “I need a supporting element here to enable sharing of this content, let’s see what we have…”)
  3. From the Pattern Library perspective, it helps to organise the elements and makes them easier to find (at least easier than the one long list we used to have).

The problem we were trying to address

However, there was no shared understanding in the team about what the distinction is exactly. Is it about the visual presentation – for example, size or visual complexity? Is it about the complexity or importance of the content? Is it about the function? What if the content alters the function? And what if the function is relative, depending on the context in which an element appears?

As a result, we used to spend a long time debating whether something is a molecule or an organism. The debates weren’t always productive, and we couldn’t afford to continue having them.

So we decided to run a workshop with designers and front-end developers, to see how we could become more efficient in classifying the elements.

The workshop

As always, we cut the interface elements out on paper (pictured above). We split into small teams and asked each group to sort the interface elements into groups (similar to a card sort), in the way that made sense to them, rather than the way they were already organised in the pattern library. The idea was just to see what groupings people would come up with.

The results

The results of the workshop were fairly inconclusive. The teams classified the modules in a variety of ways and ultimately ended up with different groupings.

However, there were clearly two distinct types. We all picked up that some modules could be used on their own, while others could only work only as part of another module. For example, these two components are quite different, both on the functional and presentation levels:

Two different types of interface element

The elements in the first group (which the top component represents) have more of a supporting function – let’s call them “helpers”. The elements in the second group are more independent – let’s call them “standalone”.


Helpers don’t make sense on their own. Here are just a few typical representatives of this group. In our interface molecules are typically “helpers”.

Examples of "helper" interface elements


The “standalone” elements can “survive” on their own – they can be viewed as their own self-contained units of content and functionality. Typical representatives of standalone modules on FutureLearn are:

Examples of "standalone" interface elements

In our interface, organisms are typically “standalone”.

So far it makes sense. Molecules primarily support other interface elements. Organisms are primarily self contained and can stand on their own.

Helper or standalone?

However, many elements fall somewhere in between. The ones that fall in between can in theory belong to either group, depending on two main factors – content and context. Content and context are of course subject to change, which makes it difficult to classify those elements. Here is a  typical example of such module:

An example of an element that falls between helpers and standalones

On the surface this looks like an organism (it’s a fairly complex element which contains a fair bit of content). However, it can’t really stand on its own. It’s not clear what exactly you’re sharing, and which course will start in 2 days. But imagine that we changed the content, gave it a more meaningful title, and referenced the title of the course. Suddenly this module can stand on its own.

Our interface abounds with elements like those, that don’t fall clearly in one of those two buckets. Here’re just a few of them:

More examples of elements that fall between helpers and standalones

The takeaways

Even after a year of working with atomic design there is still no clarity and shared understanding in our team about how interface elements should be classified. But maybe it’s OK. There isn’t always the “right” way to classify and organise things.

One thing we learned is that we should be more flexible in deciding which group a module belongs to. Rather than involving the whole team in the debate, the designer and developer who introduce a new module ultimately should decide whether it is a molecule or an organism. The rest of the team should accept their decision, unless they have strong, well-grounded objections.

When thinking about complexity of elements, it helps viewing molecules as “helpers” and organisms as “standalone” modules. If an element doesn’t clearly fall into either group, asking these questions may help:

  • Is this more of a supporting element or a standalone one?
  • Would it normally be part of something else and be reused within various components? (probably molecule)
  • Is it a well defined and relatively independent part or section of a page? (probably organism)

If you work with atomic design, we’d love to hear your thoughts. Do you see the value in separating molecules from organisms? If so, how do you distinguish the two? Tell us in the comments below. You might also be interested in design roles at FutureLearn.

Category Making FutureLearn

Comments (5)


  • sherab lham


  • Rob Belics

    In my case, I’m not concerned about standalone or helpers. I would stop at calling them organisms and atoms and molecules. An organism, to me, is something that is complete for what it does and can be placed wherever I want it. A molecule is only part of an organism to make that organism complete. Atoms make molecules complete. What those individual components do, does not matter.

    I’m still learning, though. While I’ve thought about this method for months, I only started using this method on a project I started I started a few days ago.

    • Alla Kholmatova

      Thanks for your comment Rob! That’s a really interesting way of thinking about this – in terms of how “complete” the elements make each other. But isn’t completeness sometimes a relevant thing? For example, comment blocks in a thread make the thread complete. But aren’t the blocks complete in themselves, as units of content? Would you then say that the whole thread is an organism or an individual comment block?

  • Paul Stonier

    Even working solo on a pattern library, I’ve been running through the same dilemma of deciding whether to classify something as an organism or a molecule. I’ve actually been wishing I had another level of classification between molecule and organism or molecule and atoms. When it comes to nesting modules, I either have to work less DRY or nest molecules into molecules. Am I overcomplicating it?

    • Karl

      It would probably help if this pattern library went atoms > elements > molecules > *compounds* then organisms. Creating complex compounds (or organisms) from different molecules whether nested or combined stretches the analogy, but not necessarily what you’re actually doing in CSS. I think we all get hung up on it (and naming stuff), so just pick an approach that works for that project and move on 🙂