Monday, February 19, 2018

MCD - API Design Associate tips

As MuleSoft partners, in IO Connect Services we care about constant education and certification for all its employees. In late January I presented and passed the exam for the MuleSoft Certified Developer - API Design Associate certification. MuleSoft recommends the Anypoint Platform: API Design course, which costs $1500 USD for 2 days. Here I’m sharing my findings that helped me to pass this exam.

Preparation guide

It all starts with what is covered in the exam. As you may know by now, MuleSoft publishes a preparation guide for all the certifications they have. For this particular topic, you can find the course guide here.

This guide will help you to know which are the topics you have to know in order to pass this exam. In summary, you will have to know the following:
  • RESTful basics.
  • HTTP details in order to implement such APIs in a RESTful approach.
  • SOAP basics.
  • API-led connectivity lifecycle.
  • RAML 1.0.
  • Design APIs.
  • Define APIs using RAML1.0.
  • Document APIs.
  • Secure APIs.
  • Test APIs.
  • Publish APIs on Anypoint Exchange.
  • Version best practices.

RESTful and SOAP basics.

RESTful and SOAP have been around for some time now. Nevertheless, it’s good to go back to basics from time to time. I’ve found this website that gives clear statements about basics and best practices when designing a RESTful application.

Make sure the effect of the HTTP specification on a RESTful endpoint. HTTP codes, headers, request, responses and more are covered in the exam. Make yourself comfortable with this topic as it’s very important for the design of an API.

Unlike RESTful, SOAP is an industry standard, one good reference is the W3C website: 

RAML 1.0

RESTful API Modeling Language, or RAML, is a standard to document APIs for RESTful applications. MuleSoft uses this standard in order to design and define APIs in Anypoint Platform and in the Mule runtime.

The first place you should look at is the specification itself.

But if you’re a tutorial person, you can use the RAML 1.0 tutorial.

Make sure you can write an API in RAML with nothing but a notepad. You will get some RAML snippets and will have to answer those questions based on them. This means you have to know whether the syntax is correct and what those snippets mean to the question. Also, lots of questions will come up, like syntax, design best practices, versioning best practices, and security. This is one of the most important topics in the exam as it’s the core of the API design in Mule.

One more thing, I’ve found a lot of people who think that RESTful is JSON. This is not true at all. While the usage of JSON in RESTful APIs is widely used, remember that it also supports XML and other payload formats via content-type header reference. This is particularly true for RAML as it can serialize objects based on the content type you specify in the document.

API-led connectivity and lifecycle

MuleSoft has a set of best practices for APIs. This is very well documented as API-led connectivity. You can get a quick view here.

Also, MuleSoft has very specific products and practices to manage the lifecycle of your APIs through the Anypoint Platform, such as API designer, API portal and Exchange. Make sure you know all these products inside out. As part of the lifecycle management, be sure you understand the role of each product in it. To start looking into these components, see this link:

One resource I knew recently is the API Notebook. A tool for writing API tutorials that you can share with your peers and that runs JavaScript snippets.

Be sure to know the API of this, you can find it here:


In my experience taking this exam, I noticed HTTP and RAML specifications are covered extensively. In the HTTP spec side, I got a bunch of questions about codes, requests formats, responses and headers in order to define an API properly.

I strongly advise you to get familiar with the API lifecycle management products in Anypoint platform. Moreover, do your own study projects on these products. Design an API from scratch using API Designer, publish it and make it discoverable within your organization. This will help you to understand MuleSoft’s practices and products while you study the specs as well. Will save you a little of time.

Let me know your experience about this exam. Write any comment and let’s help others looking for help on this topic.


IO Connect Services -

IO Connect Services - MuleSoft partnership -

API Design course overview -

API Design course guide -

REST API Tutorial website -

W3C SOAP tutorial -

RAML Specification -

RAML 1.0 tutorial -

API-led connectivity -

API Lifecycle management -

API Notebook -

API Notebook guide -