The key differences between Junior, Mid-level and Senior developers

In this article we explore the subject of levels of expertise, as these relate to software developers.

You will see how education, skills and personal traits all play an important role in Information Technology, just as they do in any other types of engineering, whilst also acknowledging that there are other very important qualities a developer must have, in order to earn their “Senior’s” badge.

So, the first topic we are going to look at is: What are the key differences between JuniorMid-level and Senior developers.

Then, to finish, we’ll take a quick look at how to recognize people with Systems Architect qualities amongst Senior developers.

The Comparison

To start, let’s look at the dictionary definition of an expert.

Expert – someone who’s gained a special skill or knowledge of a subject and is a candidate to become a skilled professional in that area.

When considering the qualities needed at each of the three levels, experience, in terms of age is not the key factor in determining the level of expertise. There are developers with 10+ year experience in the industry who would qualifying only as Junior level developers, conversely there are young people who become Senior developers in just couple of years.

It is important to bear in mind here that if you need to solve a business issue by developing software and then you find an expert or a group of experts you would like to dedicate the task to, there is always an element of risk involved, but before we look at potential problems, let’s focus on the main topic of our article and see how Junior, Mid-level and Senior developers differ from each other.

Junior developer

Required qualities for working at this level:

  • Relevant educational qualifications, including knowledge about Information Technology from both a software (primary) and hardware (secondary) perspective;
  • An understanding of how software interacts with, and depends on, hardware;
  • Knowledge of basic principles of programming;
  • Knowledge of at least one programming language with the ability to write basic program code;

Negative traits:

  • Can lack a sense of responsibility for what they do;
  • Cannot work independently, needing training, supervision and excessive quality control;
  • Sometimes lack the ability to learn independently;
  • Poor debugging skills;
  • Poor understanding of business problems and situations;
  • Write inefficient and hard-to-read code;
  • Rarely produce code without bugs;
  • Not fully aware of best practices;

Mid-level developer

Required qualities for working at this level:

  • Knowledge of several programming languages and technologies;
  • Can write programming code independently, provided that the business case is first analyzed and explained to them in terms of the software development needed;
  • Knowledge of, or at least awareness about best practices in the industry with a tendency to use them;
  • Can carry out other, basic dev-ops tasks in addition to software development;
  • Able to carry responsibility;
  • Acceptable debugging skills;
  • Can sometimes communicate directly with business people to clarify minor details in relation to the given task;
  • Can write simple unit tests;

Negative traits:

  • Produced code always needs to be reviewed and tested;
  • Lack understanding of the importance of different tasks;
  • Lack understanding of the importance of functional units of the software;
  • Responsibility tends to disappear at important moments;
  • Rarely think about how their work influences other parts of the software;
  • Don’t pay much attention to the readability and structure of the software code;
  • May not be very keen to gain new, or extra knowledge – feel happy with the status quo. This trait usually is the key factor as to why people often get stuck in this level for a long time or, in some cases, forever;
  • Lack the will to take care of complicated tasks voluntarily;
  • Debugging skills are sometimes not good enough to solve issues outside of their “comfort zone” or area of knowledge;
  • Can write tests of average complexity;

Senior developer

Required qualities for working at this level:

  • The person is an expert (remember the definition mentioned above);
  • Can communicate with business people about business processes;
  • Can transform business processes into programming code;
  • Take responsibility for the dedicated tasks;
  • Tend to think about the software project in general, often outside the scope of their dedicated tasks;
  • Think about “context” when applying theory;
  • Keen to learn new technologies, follow trends and incorporate best practices;
  • Consistently strive to improve the quality and structure of previously written code;
  • Can write sophisticated tests;

Negative traits:

  • Tend to focus more on the technical side of the solution rather than thinking about the business value of the feature and its ease of use;
  • Cannot always match together several systems and put together the whole scope of the project;
  • Can unnecessarily overcomplicate technical solutions, whilst paying less attention to the financial aspects of the project in terms of project costs and ROI;

Of course, there are many different personalities and skills levels and each individual might exhibit some good or some negative traits from each and every level mentioned above.

Everyone has a talent for something, it’s a case of making careful judgments, defining the need and finding the right application for any given talent.

Risk factors and the probability of failure

Now let’s get back to the previously mentioned topic about risk factors and the possibility of failure, which will always be present even if you have gathered together a group of Senior software developers.

Having listed the qualities and negative traits of the three developer levels, at some time, a problem may develop which can sometimes stay hidden for a long time. The issue here is that even a good Senior developer may fail when involved in a large, sophisticated project.


Engineering is not just about providing solutions, it’s about providing EFFICIENT solutions!

Because they are used to focusing more on the technical side of things, Senior developers may not think through all the options and challenges of the business processes of the project, and this may lead to:

  • Underestimation;
  • Architecture which eventually blocks further development of the software;
  • Issues with the realization of the business process.

There is a saying: “What the customer wants is not what customer needs”. Although we mentioned earlier that a Senior developer is capable of turning business processes into programming code, there is one more very important aspect to take in account. Without paying close attention to the relationship between each business process, it may turn out that the overall functionality of the developed software is faulty, or the software is hard to use, and this is generally as a result of:

  • Either, incorrect or ambiguous business process definitions;
  • Or, descriptions of business processes which aren’t well optimized;

The trick here is to go deep into understanding the business, before planning the software, so that the best possible solution is developed.

So, for larger or more complicated projects what you should be looking for is a Systems Architect.

How is a Systems Architect different from a Senior developer?

Although both the Senior developer and the Systems Architect roles involve tasks of planning the design and architecture of the Information System being developed, there are some functions that the Systems Architect must be capable and should be doing in addition.

The Systems Architect must:

  • Be an expert (remember the expert definition we had before)
  • Have a broad overall life experience, giving them the ability to understand the business issues being solved;
  • Be able to quickly jump into the business area of the project and understand this in detail;
  • Come up with and suggest the best possible solutions, in conjunction with the two previous points. It is often the case that suggestions are not related only to the technical aspects, but are actually better or more efficient implementations of the business process itself;
  • Ensure the coexistence of all aspects of the project as one integrated system;
  • Be responsible for the overall quality of the system, (whereas a Senior developer is responsible only for certain tasks);
  • Understand the “Big Picture” and be able to visualize the whole system before it is built;
  • Be responsible for important decisions (ones which cannot be easily “undone”) and the overall success of the project;
  • Be able to build and unite teams and other parties involved into the project
  • Be able to step in when critical issues arise, suggest a working solution or fix the issues themselves;
  • Be able to develop at least the basics of system integration and performance tests;

The list could be continued; however, these are the core qualities a System Architect needs to have. In some cases, the Systems Architect may lack some of these qualities if they are provided by some other team member, such as project manager or product owner, but if you are looking for the “Universal Soldier” and “Go-to-do-any-project” guy, it is best if all of these qualities are present.

In summary

Software developers are not just clones of one particular type of person. Personal characteristics play a big part in their ability to perform one or another of the tasks required, therefore when looking for a certain type of developer(s), try not pay too much attention to overall experience in terms of years or some standard description of each role that you can find on the internet.

Instead, pay close attention to the personality, sense of responsibility and presence of the person from a professional perspective. The right assessment of these characteristics may well give you a huge benefit in the long term, whereas focusing only on technical skills may result in you acquiring a static asset who will remain static in the future.

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