The Ultimate Hiring Guide to Developer Skills & Roles
Digital transformation is no longer “in the near future.” It’s happening right now.
Here are some interesting statistics about digital transformation:
- By 2023, companies are predicted to spend 2.3 trillion US dollars on technology and services that enable digital transformation worldwide compared to 1 trillion dollars spent in 2018.
- Digital transformation roles made up for 40% of overall ICT full-time employment worldwide in 2019 and are projected to increase to 52% by 2023.
- 46.4% of respondents claimed that their organizations' demand for advanced analytics increased significantly or moderately due to COVID-19.
And as a result of the acceleration of digital transformation, every company is now a technology company. In order to have the right technology, you need the right talent.
In an effort to help companies continue to innovate and adapt to this digital landscape, we’ve put together a list of the most sought-after developer skills, broke them down based on level (basic, intermediate, advanced), and shared the most in-demand developer role definitions and qualifications.
Continue reading for a list of developer skills or jump to roles & qualifications.
Comprehensive List of Developer Skills
.NET Core is an open-source cross-platform framework. .NET Core apps can be created using multiple programming languages.
- Basic: .NET Basic Skill level requires an understanding of .NET Classes, facilities for Input and Output, transforming data, and implementing simple REST API Services.
- Intermediate: .NET Intermediate Skill Level includes configuring data access, exploring .NET Core and Framework, the common language infrastructure, assemblies, and developing localized applications.
- Advanced: .NET Advanced Skill Level includes understanding asynchronous and parallel programming, exploring .NET security guidelines, and memory management.
- Basic: Basic Skill level includes understanding the use of components, TypeScript in Angular, MVC Framework, two-way binding, and form validation.
- Intermediate: Intermediate Skill level includes the use of Routing, NgModules, Observables for data transmission and event handling, Dependency Injections, and APIs to transport data over HTTP/S.
- Advanced: Advanced Skill level includes understanding design patterns, requirement specifications, unit testing, and browser console debugging.
Ansible Playbooks are utilized in configuring applications, servers, large networks, and systems. Automating tasks such as rolling updates becomes easy with Ansible Playbooks and modules.
- Basic: Basic Skill level includes configuring a playbook, controlling tasks, play behavior, and performing simple bash automation tasks.
- Intermediate: Intermediate Skill level includes configuration of applications and systems, using applications REST APIs and being able to test the Ansible code.
- Advanced: Advanced Skill level includes advanced automation involving security and cloud.
4. Apache Kafka
Apache Kafka makes it possible for large-scale data movement with high reliability. This key competency includes Understanding Apache Kafka Architecture, Kafka Clusters, Kafka Messaging Systems, Understanding Apache Kafka Partitions and Brokers, and Kafka Producers and Consumers, among others.
5. Apache Spark
Apache Spark is an open-source software framework built on top of the Hadoop distributed processing framework.
- Basic: This competency area includes installation of Spark standalone, executing commands on the Spark interactive shell, Reading and writing data using Data Frames, data transformation, and running Spark on the Cloud, among others.
- Intermediate: This competency area includes combining and analyzing data, performing data aggregations, configuring data sources and sinks, performing tuning, monitoring Spark jobs, performing transformations, and running SQL queries on streaming data, among others.
- Advanced: This competency area includes installation of Spark standalone, executing commands on the Spark interactive shell, Reading and writing data using Data Frames, data transformation, and running Spark on the Cloud, among others.
Amazon Web Services (AWS) is a platform that offers multiple cloud computing services from data centers around the world.
- Basic: Basic Skill Level includes launching secure Amazon EC2 instances with auto-scaling policy, configuring an Amazon S3 bucket for static website hosting, deploying a serverless application, securing an Amazon S3 bucket, among others.
- Intermediate: AWS Intermediate Skill Level includes creating cloud notification using SNS, deploying an application using Elastic Beanstalk, understanding CloudFront distribution for content stored in Amazon S3, creating a CloudWatch monitoring alert, exploring DynamoDB, among others.
- Advanced: AWS Advanced Skill Level includes analyzing data in S3 using Athena, utilizing the AWS CLI to manage resources, data migration, automating code deployments, among others.
Bash or Bourne-Again SHell is a command interpreter and a scripting language widely used as a default across Linux-based operating systems.
- Basic: The core competencies include theoretical fundamentals of Bash, common commands, variables and operators, conditional and loop statements, I/O operations, and ability to basic Bash scripts.
- Intermediate: The core competencies include advanced commands, using regular expressions, understanding, and usage of piping, file handling, trap and signals in bash, functions, and usage of command-line arguments.
- Advanced: The core competencies include error handling, asynchronous commands, ability to build a command-line tool, and usage of /dev/null.
C# is a general-purpose, object-oriented programming language designed for Common Language Infrastructure (CLI), and widely recognized for its structured, strong-typing, and lexical scoping abilities.
- Basic: Basic Skill level includes understanding the structure of C# programs, types, and Variables, basic OOP, Properties and Indexers, Collections, Exception handling, among others.
- Intermediate: Intermediate Skill level includes understanding the generic system, using anonymous methods, closures, and lambda syntax, Language Integrated Query (LINQ), resource management, and use of dynamic types, among others.
- Advanced: Advanced Skill level includes understanding Asynchronous programming, Reflection, Unsafe code, and Expression trees.
9. Code Quality
When multiple developers work on the same codebase, it is important to follow best practices to make sure unintentional patterns and syntax errors do not get committed. The competency area includes understanding the benefits of writing code that is modular, reusable, maintainable, and secure.
Cascading Style Sheets (CSS) are primarily used to enable text styling, tables, and to format the layout of Web pages. The competency areas include exploring Cascading and Inheritance, exploring text styling fundamentals, understanding the use of layouts in CSS, understanding the boxing of elements in CSS, among others.
11. Data Modeling
Data Modeling includes various techniques for modeling the data for storage in databases. Basic Skill level includes estimating probabilities using Bayesian modeling, understanding Linear regression, Logistic regression, and predicting labels to name a few.
12. Data Visualization
Data visualization is a key aspect of data analysis that allows for exploring and understanding data. Basic Skill level includes creating Data Visualizations, displaying the underlying frequency of data, displaying data trends, and using heat maps, among others.
13. Data Wrangling
Data Wrangling includes gathering, selecting, and transforming data to make them appropriate for analytics and machine learning. It also includes data cleaning, imputation, summarization, aggregation, normalization. Basic Skill level includes Outlier/Anomaly Detection, cleaning data, transforming categorical data to numerical data, grouping data based on values, and joining data, among others.
Django is an open-source web application framework based on Python, with a variety of features built-in that can be used to develop applications with ease and speed.
- Basic: Basic Skill level includes understanding key concepts, such as Models, Views, Templates, and URL configuration, among others.
- Intermediate: Intermediate Skill level includes the ability to implement email for communication and perform logging which can be used for debugging the application as required.
- Advanced: Advanced Skill level area includes performing complex database related operations using Django models in conjunction with Class-based views and the use of appropriate URL mapping as required. Understanding Templates, Authentication, and the ability to implement Rest APIs, customize Django Admin, among others.
Docker is a platform that is designed to make it simple to create, update, deploy, and run containerized applications.
- Basic: Basic Skill Level includes building Docker Images and Docker Files, creating, deploying, and running simple applications, working with .NET Containers, among others.
- Intermediate: Intermediate Skill level includes building images, understanding of basic DevOps commands for docker, Tags, and Labels, and running multiple services in a container, among others.
- Advanced: Advanced Skill level includes running commands inside a container, learning how to extract metrics, adapting stronger security practices, and working with volumes, among others.
Google Cloud Platform (GCP), offered by Google, is a suite of modular cloud computing services including computing, data storage, data analytics, and machine learning, along with a set of management tools.
- Basic: This competency area includes deploying Google App Engine instances, deploying and managing Google Cloud Functions, creating and managing Google Storage buckets, among others.
- Intermediate: This competency area includes deploying applications Compute Engine, advanced App Engine deployments, Google Kubernetes Engine, using more advanced database solutions, using shell-like solutions to manage Cloud services, among others.
- Advanced: This competency area includes in-depth Cloud Identity and Access Management, advanced data solutions, more advanced deployment options, services like Pub/Sub, Cloud CDN, Cloud Load Balancing, among others.
Golang is a popular language invented by Google in 2007. It is statically typed, and a compiled programming language. It is a common language that is used with cloud computing technologies, container orchestration toolings such as Docker and Kubernetes, ease to build CLI tools, web services, and is popular tools for building DevOps and site reliability engineering tools.
- Basic: The core competencies include covering basic language features of Golang, simple data structures, arrays, maps, data types, and interfaces.
- Intermediate: The core competencies include working with functions, understanding named returned parameters, pointers, file handling, and error handling.
- Advanced: The core competencies include learning about goroutines, mutexes, and channels, interfacing with storage, working with mock objects, and HTTP endpoint testing, among others.
The Hadoop open-source software framework is widely used for reliable, and scalable distributed computing on a cluster of machines.
- Basic: This competency area includes understanding Single node cluster in a standalone mode, in pseudo-distributed mode, running shell commands to interface with HDFS, performing parallel processing tasks, among others.
- Intermediate: This competency area includes implementing advanced parallelism, implementing Counters, performing basic queries, and subqueries in Hive, among others.
- Advanced: This competency area includes performing ETL operations using Apache Pig, Apache Cassandra NoSQL database, optimizing task execution on Hadoop using Tez, among others.
A high-level programming language used to create complete applications that may run on a single computer or be distributed among servers and clients in a network.
- Basic: Basic Skill level includes using common language features in Java, class hierarchies, design patterns, among others.
- Intermediate: Intermediate Skill Level includes Multithreading in Java, Working with Networking in Java, and Collections and Serialization.
- Basic: Key competency includes Functions, Events, and Error Handling, Currying, Hoisting, Scope, Inheritance, among others.
- Intermediate: This key competency includes Design Patterns, Memory management, concurrency model, and event loops, among others.
Jenkins is a free and open-source build and test automation server-based system written in Java. This key competency area includes configuring project builds, scheduling builds, setting up email notifications, and creating scripts for proper backup and restore of the Jenkins server.
Kubernetes (K8s) is an open-source system for containerized applications. It allows you to automate the deployment, scaling, and management of containers at scale.
- Basic: This competency area includes Kubernetes Installation and Configuration, deployments, and clusters, working with Kubernetes services to access deployments, creating configs, and secret data, among others.
- Intermediate: This competency area includes working with Stateful Applications, accessing the Kubernetes Dashboard, working with Labels, among others.
- Advanced: This competency area includes working and accessing Kubernetes and Application logs in a cluster, debugging, network policy, performance tuning, among others.
24. Language Proficiency
Understanding all of the rules, features, and mechanisms of a programming language, and optimizing for simplicity, accuracy, and modularity within the rules of the programming language is key to implementing solutions. This competency area includes identifying what makes a developer proficient in a given programming language.
Linux refers to the family of operating systems based on the open-source Linux Kernel [first released in 1991] with a largely Unix-like interface. This family of operating systems is distributed and specialized for varied purposes, such as desktops, smartphones, mainframes, edge computing devices, etc. Linux was solely built as an open-source project and today is the most widely used family of operating systems in the world.
- Basic: The competencies include theoretical fundamentals, basics in bash, usage of package manager, text editors to edit files, and an understanding of the Linux boot process.
- Intermediate: The core competencies include usage and understanding of secure shell (ssh), process and memory monitoring and management, filesystems, and an understanding of the init process and job scheduling.
- Advanced: The core competencies include an understanding of desktop and window managers, theoretical fundamentals, and utilizing the networking layer in Linux, inter-process communication, and user management for the administration of a Linux system.
26. Machine Learning
Machine Learning, a subdomain of artificial intelligence, allows computers to produce output without being explicitly programmed.
- Basic: This competency area includes using feature selection, and model selection, selecting, using, and optimizing machine learning models, procuring data, performing basic operations on data, among others.
- Intermediate: This competency area includes using the One-Hot encoding technique, creating new features using feature engineering, record sampling, running inference on a pre-trained machine learning model, among others.
- Advanced: This competency area includes training a brand new machine learning model from scratch, evaluating the performance of a machine learning model, tuning a machine learning model to achieve better performance, among others.
MongoDB is a document-based No-SQL database. MongoDB stores all schema and records using a JSON-like syntax and makes use of collections and documents.
- Basic: This competency area includes creating a new database with a new collection, users, collections, inserting, and returning documents, among others.
- Intermediate: This competency area includes querying for documents, performing various operations on documents such as updation, insertion, removing fields, deletion, among others.
- Advanced: This competency area includes inserting and sorting records, limiting query results, counting and aggregating documents, among others.
- Basic: Key competency includes Package and Modules Management, and understanding the use of Callbacks, Event Loop, Event Emitter, Buffers, Streams, File Systems, among others.
- Intermediate: Competency includes understanding Event-Driven Architecture and Concurrency, and Scaling and Packaging.
- Advanced: This key competency includes combining REST API Services and business drivers to achieve the best results.
29. Problem Solving
At its core, problem-solving focuses on the study, understanding, and usage of data structures and algorithms.
- Basic: The competency area includes basic Data Structures and Algorithms.
- Intermediate: Competency area includes usage of HashMaps, stacks, queues, heaps, and analyzing run-time complexities and space complexities, among others.
- Advanced: This competency area includes working with Data Structures such as Trees, Graph Traversal, using Dynamic Programming and Specialized Algorithms, among others.
Puppet is an open-source (and enterprise) tool that is used for configuration management, deployment automation, and provisioning (AWS). It uses a pull configuration paradigm and makes it easy to manage large infrastructures through simple abstraction.
- Basic: This competency area includes an understanding of configuration management, Puppet architecture, basics of Puppet DSL, among others.
- Intermediate: This competency area includes an understanding of basic manifests in Puppet, setting an attribute value for a resource, installing a package, creating a file, writing simple templates, exploring Puppet Forge, setting up Puppet for a cluster, among others.
Python is an interpreted, high-level, general-purpose programming language, and one of the most popular languages for rapid development across multiple platforms. Python enables developers to focus on the core functionality of the application by abstracting common programming tasks.
- Basic: This competency area includes understanding scalar types, operators and control flow, types in Python, modular program design, among others.
- Intermediate: This competency area includes understanding Closures and Decorators, using magic methods in Python, Collections, Exceptions, Errors, and using Context Managers.
R is a software environment for statistical computing and graphics. R is commonly used for Data Analysis, Statistical Computing, Machine Learning algorithms, and scientific research. This competency area includes fundamentals of the R programming language, understanding Data Frames, Packages, and Data Reshaping, using Data interfaces, among others.
- Basic: This competency area includes understanding basic routing, rendering elements, state management, handling events, among others.
- Intermediate: This competency area includes managing controlled components, routing with Params, fetching, and processing data using web requests, among others.
- Advanced: This competency area includes integrating framework knowledge with business logic, creating and running comprehensive unit tests on the React application, Debugging, Hooks, among others.
34. REST API
A RESTful API makes it possible for remote execution of an application's capabilities by supporting standard HTTP methods, error handling, and other RESTful mechanisms.
- Basic: This competency area includes usage of the GET Request, and exploring basic functionalities.
- Intermediate: This competency area includes usage of the GET Request, and exploring basic functionalities.
- Advanced: This competency area includes building a complete REST API Service.
Ruby on Rails (RoR) is a framework, primarily helping developers build websites and applications, abstracting and simplifying repetitive tasks.
- Basic: This competency area includes understanding the RoR Model/View/Controller (MVC) framework, understanding the Rails Directory Structure, working with rake tasks, migrations, records, and rail routes.
- Intermediate: This competency area includes understanding the RVM (Ruby Version Manager), setting up databases and working with migrations, exploring advanced active record operations, and caching, among others.
- Advanced: This competency area includes working with Refactoring large Rails codebases, working with vast test suites, the know-how of building a Gem, microservices, security, and performance, and other key concepts such as debugging, testing, and deployment.
Ruby is an interpreted, dynamic, open-source programming language with a focus on simplicity and productivity.
- Basic: This competency area includes exploring the basics of Ruby programming, including constructors, operators, loops, methods, and objects. Also includes learning to write simple modules, working with Arrays, and input-output, among others.
- Intermediate: This competency area includes understanding Ruby objects and their functionalities, working with Ruby Built-ins, Hash, Range, and Set, exploring Collections and Enumerables, building simple regular expressions, reading, and writing to JSON and XML file types, directory operations, among others.
- Advanced: This competency area includes advanced operations with Ruby Objects and Methods, working with some complex regular expression operations, modifying Ruby classes and modules, working with Proc, Block, and Lambda, among others.
Selenium is an open-source Web UI automation testing framework. Selenium supports automation across different browsers, platforms, and programming languages.
38. Spring Boot
Spring Boot is an extension of the Spring Framework that helps developers build simple and web-based applications quickly, with less code.
- Basic: Competency area includes configuring a Spring MVC application, Basics of the Spring framework, working with REST APIs, writing a unit test for a simple application, among others.
- Intermediate: Competency area includes using Spring Boot’s auto-configuration, packaging, and deploying a simple application, implementing exception handling, among others.
Structured Query Language (SQL) is an industry-standard query language that works with relational databases. Unlike some earlier systems, queries are performed at the server and only the results are passed to a client. This resulted in the ability to work with large databases efficiently over a network.
- Basic: This competency area includes understanding simple queries, relationships, and aggregators.
- Intermediate: This competency area includes working with complex joins, unions, and subqueries.
- Advanced: This competency area includes the ability to demonstrate an understanding of query optimization, data modeling, Indexing, window functions, and pivots in SQL.
40. System Design
System design is best used to provide sufficient detailed data and information about a system and enable the implementation consistent with architectural entities as defined in models and views of the system architecture. This key competency explores Scalable Systems and Visualizing and Designing complex systems.
41. Technical Communication
Technical communication is used to make information about technical products, services, and processes clear and understandable. It is the ability to convey thoughts, designs, ideas, and specifications in a clear and concise manner.
Terraform allows you to build, change, and version your infrastructure using infrastructure as code techniques.
- Basic: This key competency includes Deploying Terraform Configurations, Launching and changing an AWS instance using Terraform, Working with the Terraform Registry, resources, and outputs, among others.
- Intermediate: This key competency includes working with the Docker Provider, importing existing Infrastructure, working with Terraform Secrets, Conditionals, Counters, Functions, and working with Variables.
- Advanced: This key competency includes understanding backends, using the MySQL, local, and time provider to manage database instances, debugging, modularizing, and understanding the Terraform Graph API.
For more information on each skill, please visit our HackerRank Skills Directory.
High-Demand Developer Role Definitions & Qualifications
1. Software Engineer
What is a software engineer?
A software engineer is hired to build customized systems and solutions for a specific customer. They have extensive knowledge of programming languages, software development, and computer operating systems. They apply engineering principles to the design, development, maintenance, testing, and assessment of computer software.
What are some fundamental software engineer skills?
- Code Quality
- Language Proficiency
- Problem Solving
- REST API
- Technical Communication
What are some common software engineer interview questions?
- How do you build a search for Gmail?
- Describe some bad code you’ve read or inherited lately.
- When do you know your code is ready for production?
2. Front-End Developer
What is a front-end developer?
What are some fundamental front-end developer skills?
- Code Quality
- Problem Solving
- Technical Communication
What are some common front-end developer interview questions?
- What frameworks have you used and what are the pros and cons of each?
- What are some ways a server can communicate with a client?
3. Back-End Developer
What is a back-end developer?
A back-end web developer is responsible for server-side web application logic and data storage. While front-end developers focus on the UI, back-end developers write the web services and APIs used by front-end and mobile application developers.
What are some fundamental back-end developer skills?
- Code Quality
- Problem Solving
- REST API
- System Design
- Technical Communication
What are some common back-end developer interview questions?
- What is your favorite programming language and why?
- What is the difference between acceptance testing and functional testing?
- What are the differences between SQL databases and MongoDB at a high level?
- What are some performance testing best practices?
4. Full-Stack Engineer
What is a full-stack engineer?
A full-stack engineer works with both the front and back ends of a website or application. They can tackle projects that involve databases, building user-facing websites, and work with clients during the planning stages of this process.
What are some fundamental full-stack engineer skills?
- Code Quality
- Problem Solving
- REST API
- Technical Communication
What are some common full-stack engineer interview questions?
- When presented with a new project, how did you select the tools and technologies involved?
- What would you say was your best implementation experience?
- Say you had to write an endpoint for checking if a resource exists. What path and method would you use?
- What are 5+ ways you could optimize a website to be as efficient and scalable as possible?
- How would you prevent a bot from scraping your publicly accessible API?
5. Data Scientist
What is a data scientist?
Data scientists gather and analyze large sets of structured and unstructured data. Through computer science, statistics, and mathematics, they analyze, process, and package insightful data to inform key decisions within organizations.
What are some fundamental data scientist skills?
- Apache Spark
- Code Quality
- Data Modeling
- Data Visualization
- Data Wrangling
- Machine Learning
- System Design
- Technical Communication
What are some common data scientist interview questions?
- What are the differences between supervised and unsupervised learning?
- What is machine learning?
- What is selection bias?
- How should you maintain a deployed model?
- How can you avoid overfitting your model?
- How do you perform logistic regression?
- Say you are given a data set consisting of variables with more than 30% missing values. How would you deal with them?
6. Cloud Engineer
What is a cloud engineer?
A cloud engineer commercializes, standardizes, and governs cloud computing applications. They leverage methods and tools of engineering to conceive, develop, operate, and maintain cloud computing systems and solutions. Cloud engineers are responsible for cultivating cloud resources to solve business problems.
What are some fundamental cloud engineer skills?
- Code Quality
- System Design
- Technical Communication
What are some common cloud engineer interview questions?
- What are the benefits of Cloud Computing?
- What are the cloud service models?
- What are the differences between cloud and on-premise computing?
For Further Reading on Developer Skills
- Check out HackerRank’s Skills Directory to see all the industry-certified skills we offer on our remote hiring platform.
- Digital Transformation Is About Talent, Not Technology addresses the importance of reskilling and upskilling people so that they are better equipped to adjust to change.
- Download the HackerRank’s Developer Skills Report for insight into what employers and employees know, what they’re looking for in their work, and how they see their roles evolving as technology sweeps across industries of all sizes.
- Equip yourself with the tools to pull off a great interview with Springboard’s 31 Software Engineering Interview Questions With Answers.
- For more predictions around the future of digital transformation, check out CIO’s What is Digital Transformation? A Necessary Disruption.
Planning to hire developers?
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With our Developer Skills Platform, you can:
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