Search results

Visualizing APIs with tree diagrams, partly generated with AI

by Tom Johnson on Feb 13, 2024
categories: ai api-docvisual-communication

I recently visualized both a cloud and Java API through some complex tree diagrams that showed the objects returned, with all the detail inherent in the parent/child relationships and structures. One of the primary principles of prompt engineering is to break complex tasks up into smaller ones. This principle has at least two purposes: (1) most AI chatbots can't process large amounts of text, and (2) you can more precisely direct the output from smaller inputs.

As I’ve been working with AI chatbots over the past few weeks on a particular project visualizing APIs with tree diagrams, I’ve really come to see how important these two principles are. I’ll elaborate more on the details of the prompt engineering techniques, but first, let me explain the documentation context.

I decided to create some visual diagrams that describe the APIs I work with. This might seem like an odd task, but the scenario is that we have multiple APIs (of different types — e.g., Java, cloud) with similar data, and partners struggled to navigate the reference docs to find the data they wanted to see. These APIs deliver massive amounts of data to users in various parent-child hierarchies.

I first started generating dot diagrams from proto files using an internal utility. The utility was pretty cool but had two main drawbacks: (1) the diagrams looked like spaghetti with so many lines everywhere, and (2) the diagrams didn’t link to the reference docs.

To get a diagram with links, I started creating tree diagrams. First, I was surprised to learn that AI tools can convert a chunk of JSON into a tree diagram. There seems to be some kind of logic in AI tools that can convert JSON into a tree diagram or a tree diagram into JSON, as if they were equivalent formats similar to Markdown and HTML.

For the Java API, I found that I could also convert the API’s structure into a tree diagram as well, often by just pasting in the documentation for each class! This sort of blew my mind. (It’s hard to explain in more detail, and I’m not doing it justice here, but each method gets certain objects, and those objects have attributes.)

I started with a simple tree and built out each node one by one, often just pasting in the documentation. It worked best if I started out with the high-level structure and then asked the AI to expand each node with more details. This approach seems like one that could scale to many documentation scenarios.

I also had to teach the AI the specific tree diagram style I wanted, and there were errors along the way I had to correct and fix, but by and large the AI tools made this task feasible in ways that I wouldn’t have attempted otherwise.

I realize it’s hard to get a sense of the complexity of this task without seeing the details. Unfortunately, the documentation lives behind a firewall, so I can’t share it or go into more details. But imagine a tree diagram so large and complex that you have to scroll down for a while to see it all, navigating around 10 subnodes with different levels of nesting and parent/child logic.

Here’s an example of what it kind of looks like. This diagram has been jabberwockied and doesn’t reflect the actual structure either. My diagrams were actually about 10 times this large.

root {} 
   ├─WonderWhizzleSnacker {}
   │  ├─FluffPrep []
   │  │  ├─PufTwiz {}
   │  │  │  ├─WhipFlavor {}
   │  │  │  │  ├─FlimEssence (string)
   │  │  │  │  │  └─SpinRefine (number) 
   │  │  │  │  └─SnigDust (boolean)
   │  │  │  └─GlimPolish {}
   │  │  │     ├─PixieShine (number) 
   │  │  │     └─FrumBuff (string) 
   │  │  ├─FluffDetangle []
   │  │  │   ├─BumbleFluffRetrieval (boolean) 
   │  │  │   └─WiggleSproutDisentanglement (string) 
   │  └─RootGet []
   │     ├─BumpExped {}
   │     │  ├─GinProv [] 
   │     │  │  ├─PogBake (number)
   │     │  │  └─FlibBrew (string) 
   │     │  └─SnorgNav {}
   │     │     ├─FlutRefuel (number) 
   │     │     └─HobEcho (boolean) 
   │     ├─RootSort (string) 
   │     └─FabPick {}
   │        ├─WhifOrch {}
   │        │   ├─BanLull [] 
   │        │   │  ├─HumpHarm (number) 
   │        │   │  └─FluffTease (string) 
   │        │   └─FlufUntang (boolean) 
   │        └─TwitGrove {}
   │           └─GrifDistract (number) 
   ├─WhizgigBuild {}
   │  ├─FidFrame []
   │  │  ├─SnurdJig {} 
   │  │  │  ├─FizWrang (string) 
   │  │  │  └─KlopAppease (boolean) 
   │  │  └─QuigWeld {}
   │  │     └─SnizRust (number) 
   │  ├─SpinSprock {} 
   │  │  ├─WhipTight (string) 
   │  │  └─WigCal (number) 
   │  └─FizPow {}
   │     ├─Sparkle (boolean) 
   │     ├─FizzMon {}
   │     │   └─BlipTrack (string) 
   │     └─DingPrevent {} 
   ├─OpWozzle {}      
   │  ├─KnobTune {}
   │  │  ├─SnarfCalc (number)  
   │  ├─PlinkStart []
   │  │  ├─GurgleInit {}
   │  └─FrobMon {}
   │     └─WhipAssure {}
   │        └─HogEquil {}
   ├─SnickersnapScrambler {}
   │  ├─JibberCrunch {}
   │  │  ├─KnizzlePop (number)
   │  │  └─WhiffleFuzz (boolean) 
   │  └─WiggleWarp []  
   │     ├─SplortFizzle (string)
   │     └─QuiggleSnap {}
   │         ├─SplinkTweak (number)
   └─WhiffleFlummox {}
      ├─SplootScrunch (string)
      ├─WhizzTwizzle {}
      │   └─FlarpStack (number)
      └─PoggleWiggle []
         ├─SnurdlePop (boolean)
         └─Jumboflap (string)

This same tree diagram might look like this in JSON:

  "root": {
    "WonderWhizzleSnacker": {
      "FluffPrep": [
          "PufTwiz": {
            "WhipFlavor": {
              "FlimEssence": "string",
              "SpinRefine": 123,
              "SnigDust": true
            "GlimPolish": {
              "PixieShine": 456,
              "FrumBuff": "shiny string"
          "FluffDetangle": [
      "RootGet": [
          "BumpExped": {
            "GinProv": [
            "SnorgNav": {
              "FlutRefuel": 654,
              "HobEcho": false
          "FabPick": {
            "WhifOrch": {
              "BanLull": [
              "FlufUntang": false
            "TwitGrove": {
              "GrifDistract": 321
    "WhizgigBuild": {
      "FidFrame": [
          "SnurdJig": {
            "FizWrang": "fizzy string",
            "KlopAppease": true
          "QuigWeld": {
            "SnizRust": 789
      "SpinSprock": {
        "WhipTight": "taut string",
        "WigCal": 555
      "FizPow": {
        "Sparkle": false,
        "FizzMon": {
          "BlipTrack": "tracking data"
        "DingPrevent": {}
    "OpWozzle": {
      "KnobTune": {
        "SnarfCalc": 999
      "PlinkStart": [
          "GurgleInit": {}
      "FrobMon": {
        "WhipAssure": {
          "HogEquil": {}
    "SnickersnapScrambler": {
      "JibberCrunch": {
        "KnizzlePop": 123,
        "WhiffleFuzz": true
      "WiggleWarp": [
          "QuiggleSnap": {
            "SplinkTweak": 456
    "WhiffleFlummox": {
      "SplootScrunch": "glooping sound",
      "WhizzTwizzle": {
        "FlarpStack": 789
      "PoggleWiggle": [

I find the tree diagrams a lot easier to visually consume than blocks of JSON. It’s hard to see levels of nesting and which objects are at the same sibling level.

Additionally, I also had to represent both JSON and Java (for different APIs) with a similar enough tree structure as to be intelligible.

Having finished this project, it gave me a tremendous insight into our APIs in ways that I didn’t understand previously. And project managers loved it!

When I first showed it to the primary PM, he immediately wanted every element linked to the corresponding reference documentation. This meant adding hundreds of links. For the cloud API, it was fairly easy to get the links because most of the documentation was on a single page, and I just needed to discern the logic of the link paths.

For the Java API, however, the Javadoc was a lot harder to navigate, with many different pages (a separate URL for each model in the API). I had to study the link patterns to figure out the logic, but once I did, I instructed the AI how to discern the link patterns from the tree diagram. Then I had the AI write out a list of links.

I’m being cursory here and not going into too much detail. This project consumed me for two solid weeks, and I had many failed attempts and revised prompts and such before I had success.

I couldn’t add a ton of HTML links into a tree diagram without making it break lines all over the place and become unreadable. So I used Jinja scripting logic (available on our doc platform) to use variables. I created variables for each element and then added an include that pulled in all the variables for each diagram.

I then realized that different diagrams repeated some of the same element names. To get around this, I had to add a scope to the variables so that each variable name wouldn’t collide with similar variable names in other diagrams. I used AI to understand variable scoping in Jinja.

These tree diagrams might not be something that applies to many people, but for my particular scenario, the outcome is really awesome. I’m having a tough time understanding why tree diagrams aren’t more common in API documentation. They visualize complex objects in ways that I find valuable.

Regardless of whether tree diagrams make sense in other scenarios, my main point was to describe that approach I took with AI here. I used task decomposition to break down a complex project into smaller tasks. There were probably 50 smaller tasks I did before I finished the diagrams. That breakdown of complex tasks allowed me to use AI to achieve the result.

About Tom Johnson

Tom Johnson

I'm an API technical writer based in the Seattle area. On this blog, I write about topics related to technical writing and communication — such as software documentation, API documentation, AI, information architecture, content strategy, writing processes, plain language, tech comm careers, and more. Check out my API documentation course if you're looking for more info about documenting APIs. Or see my posts on AI and AI course section for more on the latest in AI and tech comm.

If you're a technical writer and want to keep on top of the latest trends in the tech comm, be sure to subscribe to email updates below. You can also learn more about me or contact me. Finally, note that the opinions I express on my blog are my own points of view, not that of my employer.