Senior Developer in 24 hours

In the realm of technology, the path to becoming a senior software developer is a journey marked by continuous learning, problem-solving prowess, and a relentless pursuit of excellence. This book serves as your compass in navigating the intricate landscapes of software development, offering a comprehensive guide to acquiring the skills that elevate you to the coveted position of a senior developer.

Embark on a transformative odyssey as you delve into the nuances of the software developement lifecycle, learn to decipher complex problems, and cultivate the art of collaboration within development teams. With real-world examples and hands-on exercises, this book not only equips you with the technical acumen required for senior roles but also delves into the soft skills and leadership qualities that distinguish exceptional developers. Whether you're a budding programmer seeking to ascend the ranks or an experienced developer aiming to stay at the top of your game, this guide is your roadmap to mastering the skill set of arguably the most trascendental occupation of the information age: software developer.

What Makes a Senior Software Developer?

In the world of software development, a Senior Software Developer is the core of the team. The people who can truly fill the role of a Senior Software Developer are few, and as such, in extremely high demand. This book is an attempt to condense the skills and traits required to make the jump from a Junior Software Developer to a Senior Software Developer. But the first step is to define what we mean by Senior Software Developer and Junior Software Developer.

Junior Software Developers are normally entry-level software developers who assist the development team with all aspects of the software development lifecycle. However, their primary role is to write code and fix bugs, normally based on well-defined tickets and bug reports. The day-to-day of a Junior Software Developer normally consists of picking up (or being assigned) a particular bug, working on it until completion, and then picking up the next bug. Besides tackling tickets, Junior Developers will become intimate with parts of the codebase, making their input valuable in other areas of the design and development process.

Senior Software Developers will spend a lot of their time writing code and closing tickets, but the value they provide goes far beyond. Senior Developers are a force multiplier that will enable Junior Developers to operate at their full capacity. In this book we are going to focus on how we can become enable the creation of better software, a skill above just writing better code.

What a Senior Software Developer is not?

Some characteristics and traits are associated with a Senior Software Developer but do not contribute directly to the effectiveness of a Senior Software Developer. For example:

Years of experience: Many times organizations, and especially Human Resource departments and recruiters, equate a lengthy tenure with a Senior position. While having multiple years of experience is typical for Senior Developers, just having those years does not provide on its own the skills that a Senior Software Developer should bring to the table.

Writing code the fastest: A Senior Developer should be able to solve problems faster, but that doesn't necessarily mean that they write raw code faster. Senior Developers are better at understanding what code should be written, what code or libraries can be reused, and what code shouldn't be written in the first place.

Intimate knowledge of the company's codebase: While many Senior Developers will have intimate knowledge of the codebase that they are working on, it is not in itself a hard requirement. One of the attributes that Senior Developers bring is the ability to quickly learn their way around a new codebase.

Junior Software Developer vs. Senior Software Developer

To plot our path from Junior Software Developer to Senior Software Developer, it's vital to understand the difference between the two. Or at the very least understand the basic role of Junior Software Developers.

Junior Developers follow a very simple workflow, where they pick up a ticket, work on the ticket until it's done, submmit their changes, and then pick up a new ticket to start the process all over again. Senior Software Developers will also work on tickets but also need to keep a more holistic view of the system. This holistic view includes:

  • Gathering and grooming requirements
  • Ensuring functional and non-functional requirements are met
  • Having an opinionated take on whether code should be written, or if alternative solutions should be used
  • Understanding the end-to-end Software Development Lifecycle (SDLC)

We'll go into a lot more detail in the next chapters, but we can summarize the main differences between Junior and Senior Developers in the following table:

JuniorSenior
Focused on ticketsHolistic view of application
Functional RequirementsFunctional and non Functional Requirements
Writes codeShould we even write this code? Can we remove this code?
Limited view of SDLCEnd-to-end view of SDLC

Architect vs. Senior Software Developer

Another persona that is often seen in the higher ranks of software development organizations is the Architect. Normally prefaced by even more enthusiastic terms such as "Enterprise" or "Solution", the Software Architect is another potential career development path for Software Developers.

Architects normally work at the organizational level, keeping a holistic view of the system, rather than focusing on an individual component level. Sr. Software Developers will focus more on their component, while also keeping an eye out to understand how it fits within the bigger picture.

Architects work mostly at the development organization level, while Senior Software Engineers work more at the team level. This means that in an organization, you will find many more Senior Software Engineers with only a few Architects.

The deliverables produced by Architects are more theoretical, think UML diagrams, design documentation, standards, and occasionally some proof of concept code. On the other hand, Senior Software Engineers will produce a lot more code, with some supporting documentation (design diagrams, standards, etc.).

It is worth noting that in other cases Enterprise Architects or Solution Architects are part of the sales organization, and as such their job is more aligned with architecting "Sales Proposals" or "RFP (Request For Proposals) Responses" rather than architecting the actual system that will be built.

Both the Software Architect and the Senior Software Developer must be thought leaders in the organization and must collaborate to bring about the vision of the organization. An architect who proposes a design that the software developer can't deliver is not contributing to the fulfillment of this vision. In the same manner, a software developer who works without understanding how their components fit in the overall organization is not contributing value to the organization.

We can summarize the main differences between an Enterprise Architect and a Senior Developer in the following table:

ArchitectSenior Developer
Holistic view of systemDeep knowledge of a component
Concerned about non Functional RequirementsConcerned about Functional and non Functional Requirements
Organization levelTeam level

Backend vs Front-end Development

It is also important to note that for the scope of this book, we're going to be focusing on backend development. While some of the topics covered in the book might apply to front-end development, the ecosystem is different enough that to achieve proficiency in either field, true specialization is required.

About the Author

Andrés Olarte portrait

Andrés Olarte has tackled multiple changes in IT, from working as a systems adminstrator, to Java Development of enterprise applications, to working as a consultant helping customer develop cloud native application.

Currently, Andrés works as a Strategic Cloud Engineer for the professional services organization at Google Cloud.

Andrés loves learning new things and sharing the knowledge. He has spoken at multiple events, such as "Chicago Java Users Group".

Andrés writes at his personal blog The Java Process.

About this Book

The book is structured around 24 chapters. Each chapter covers one topic in depth, and should be readable in one hour or less. Depending on your previously experience and knowledge, you might want to branch out and seek more information on any particular topic. Each chapter will provide a concise list of the tools that are referenced.

As part of the process of condensing the information and techniques for this book, a series of videos discussing the topics were created. The videos will listed within each chapter.

Who is the target audience of this book?

This book is geared towards "entry-level" or "junior" software developers, that want to grow their careers. If you already have the basic knowledge of how to write code, the material here will help you gain the skills to move up in your career.

In this book, we skip over a lot of basic topics, to focus on the areas where a Senior Software Developer can provide value. In this book, we are not trying to replace the myriad of coding boot camps or beginner tutorials that are out there, but rather provide a structured set of next steps to advance in your career. We also skip a formal review of Computer Science focused topics. There are plenty of sources for Computer Science theory, including preparation for CS-heavy interview questions that are popular in some companies.

If you are already a Senior Software Developer, you might find the material useful as a reference, as we provide opinionated solutions to common problems that are found in the field.

Decisions, decisions, decisions

One of the main roles of a Senior Software Developer is to make decisions.
When we hear "decision maker", we normally think of a high level executive, however software developers make tens if not hundreds of decisions every day. Some of these decisions might be small, but some might be very impactful. A bad decision when choosing a timeout could cause a mission critical system to fail, and a bad decision regarding our concurrency logic could limit how much the operations of the business can scale. In a large business, one of those bad decisions could have a price tag of thousands or millions of dollars.

For example, in 2012, Knight Capital Americas LLC, a global financial services firm engaging in market making, experienced a bug. This bug caused a significant error in the operation of its automated routing system for equity orders, known as SMARS1. Due to a misconfigured feature flag, SMARS routed millions of orders into the market over a 45-minute period.
The incident cause a loss of $450 million. 2

The decisions a software developer makes are very important, and we always must take into consideration three aspects:

  • The problem at hand
  • The technologies available
  • The context (from a technical perspective, but also from an organizational perspective)

Some of the decisions we can take on our own, for example: "How should we name a variable?" Other decisions will require consulting other teammates or external stakeholders. For larger decisions that impact the overal architecture of a solution, we might even have to negotiate to reach a concensus. The more ramifications a decision has outside our application, the more we'll have to involve other parties.

Whatever the decision, it's important to always keep in mind the context in which we're taking the decision. Many of the decisions we discuss here, might have already be defined in a large organization, and if we need to go against those standards, we need to have a very good reason to justify it.

Which brings us to another point to keep in mind: pick your battles. When trying to defend our point of view against someone with an oposing view, it's important to weigh if there's value in prevailing, while potentially spending a lot of time or burning political capital. Sometimes it's better to concede against a differing opinion, when there's marginal to choosing either alternative.

We can start by clasifying decisions into Type 1, which are not easy to reverse or non-reversable at all; or Type 2 decision which are easy to reverse if needed.

In an Amazon shareholder letter, CEO Jeff Bezos explained how we need to fight the tendency to apply apply a heavy decision making to decision that don't merit that much thought:

Some decisions are consequential and irreversible or nearly irreversible – one-way doors – and these decisions must be made methodically, carefully, slowly, with great deliberation and consultation. If you walk through and don’t like what you see on the other side, you can’t get back to where you were before. We can call these Type 1 decisions. But most decisions aren’t like that – they are changeable, reversible – they’re two-way doors. If you’ve made a suboptimal Type 2 decision, you don’t have to live with the consequences for that long. You can reopen the door and go back through. Type 2 decisions can and should be made quickly by high judgment individuals or small groups.

As organizations get larger, there seems to be a tendency to use the heavy-weight Type 1 decision-making process on most decisions, including many Type 2 decisions. The end result of this is slowness, unthoughtful risk aversion, failure to experiment sufficiently, and consequently diminished invention. We’ll have to figure out how to fight that tendency.

-- Jeff Bezos 3

With that said, it's important to understand in which decisions, we must apply a heavy and involved decision making process. Discussions can always be valuable to have, but must always be respectful.

We need to be ready to defend our decisions, so we need to think about the different trade-offs, as well as the context in which we're taking these decisions.

Throughout the book, key decision points will be higlighted in clearly marked boxes:

Decision Point

What is the priority of the tickets we have created?

Tech Stacks

Most of this book covers material that is independent of a particular tech stack. However, when it comes to practical examples, we focus on three tech stacks that are popular for backend development:

Other languages will be mentioned if they are relevant to a particular topic.

Introduction Video

1 "ORDER INSTITUTING ADMINISTRATIVE AND CEASE-AND-DESIST PROCEEDINGS,". Securities and Exchange Commission, 2013, https://www.sec.gov/files/litigation/admin/2013/34-70694.pdf

2 Popper, N. (2012, August 2). Knight Capital says trading glitch cost it $440 million. The New York Times. https://archive.nytimes.com/dealbook.nytimes.com/2012/08/02/knight-capital-says-trading-mishap-cost-it-440-million/

3 "LETTER TO SHAREHOLDERS,". Jeffrey P. Bezos, 2015, https://www.sec.gov/Archives/edgar/data/1018724/000119312516530910/d168744dex991.htm