Demand for Elixir Developers Continues to Expand
The functional programming language Elixir has exploded in popularity for the development of systems requiring concurrency, scalability, and fault tolerance. A modern re-imagining of Erlang, Elixir is now used by more than twice as many professionals; skills with these two BEAM-based languages command the highest compensation among software developers. With the popularity of e-commerce, real-time communication, healthcare, and other industries that require high performance and reliability, the steady growth of demand for Elixir software engineers makes sense.
Despite this growth, the language’s focus on advanced systems makes Elixir skills far less common than those in mainstream languages like JavaScript, PHP, or Python. The right Elixir developer can be hard to find in this relatively small talent pool, especially given the market’s need for the language’s capabilities.
This guide provides the insights hiring managers need to navigate the complexities of hiring Elixir developers. From understanding what differentiates top talent to crafting an effective job description and interview questions, you’ll learn how to attract and discern the ideal candidates for your specific project requirements.
What Attributes Distinguish Quality Elixir Developers From Others?
Elixir programmers are known for writing clean, maintainable, and high-performing code, thanks to the language’s emphasis on functional programming. Many will have experience with Phoenix — the most popular among several Elixir frameworks — enabling them to create scalable web applications. Many will also know their way around tools like Ecto to work with PostgreSQL, MySQL, and other databases.
The best Elixir developers will know how to create robust back ends with optimally designed APIs, allowing seamless service integration. They will excel in problem-solving and, thanks to a deep understanding of distributed systems, ensure scalability and fault tolerance. Their experience will often have overlapped with DevOps roles, garnering them skills in Docker and Kubernetes — tools that are often used to deploy and manage Elixir applications. And having been on various development teams, they’ll likely be accustomed to adapting to different development processes and methodologies (e.g., Scrum).
How Can You Identify the Ideal Elixir Developers for You?
Every project is unique, as is every developer, so you’ll have to understand the former before you look for the latter. For example, a real-time messaging platform may require someone skilled in concurrency and fault-tolerant design, while an e-commerce application might prioritize expertise in the Phoenix framework.
Any project with specific plans or implementations will have a highly relevant list of dependencies on adjacent technologies; it’s well worth watching for these competencies among candidates. Here are some example scenarios showing skills to keep in mind:
- In planning, your team eschewed Phoenix in favor of a more specialized framework like N2O. Alternatively, it kept Phoenix, but did so alongside Ash Framework.
- Your project relies on advanced techniques concerning a particular SQL database like PostgreSQL.
- You’re looking to hire a full-stack developer rather than having separate front- and back-end developers among your project’s team members. In this case, experience with your app’s front-end web framework (e.g., React or Angular) and intuition around user experience (UX) would be vital.
Your new hire may or may not need skills in all the technologies and tools comprising your system — it depends on their expected role.
Lastly, the years of experience separating a junior developer from a senior can make all the difference with critical projects. Senior developers have extensive knowledge of Elixir’s ecosystem and a track record of architecting high-quality applications that have proven successful at scaling.
How to Write an Elixir Developer Job Description for Your Project
Skilled Elixir developers may not contact you if your job description is contradictory or unclear. Beyond the technical skills and scope requirements you’ve already gathered, you’ll also need to know which policies may affect your hiring flexibility. Are you open to freelancers? Is the role required to be full-time? Do you need an entirely in-house team, or can they be remote? Does your project manager have the appropriate communication skills and schedule to work with team members distributed across multiple time zones? Include any relevant details.
The job description should also list required soft skills, such as problem-solving, teamwork, and communication; in all three cases, emphasizing the context is helpful. For example, you might indicate that problem-solving is required because the role includes being on-call if deployments fail, or that teamwork and communication are essential because a new hire would be expected to work closely with front-end developers and the database specialist.
Lastly, highlight the project’s goals and potential impact, whether it’s an e-commerce platform, a real-time application, or a machine learning initiative. Providing this context can help you attract candidates who are genuinely passionate about your mission.
What Are the Most Important Elixir Developer Interview Questions?
The most effective interviewer will vary their question types by including factual and discussion-oriented questions. They will also mix questions relevant to project types and key adjacent technologies — for example, about machine learning (ML), web development, and/or SQL queries, as applicable — in with Elixir-specific ones, sometimes combining these contexts. For example:
How does Elixir’s concurrency model differ from that of other programming languages? Can you explain its advantages for web development?
The Elixir programming language, its use of the BEAM virtual machine, and its shared-nothing (SN) architecture (similar to the actor model) — and how these enable low-latency operations — should be familiar topics for candidates.
One of the foundational approaches to concurrency in Elixir is the use of Elixir processes, which are more lightweight than operating system (OS) processes or threads: BEAM can manage hundreds of thousands of them simultaneously, keeping them isolated from each other yet still able to communicate via messages. This concurrency model lets developers build web applications that are fault-tolerant and distributed — and therefore highly scalable. Any worthwhile candidate should find it easy to explain this clearly; most should also be able to contrast it with the approach of another language or platform, like Node.js’s single-threaded architecture.
They might also mention that Elixir’s SN architecture simplifies debugging by eliminating contention and reducing race conditions. They should be able to explain a web development scenario, perhaps involving Phoenix Channels or the Nerves framework, that showcases Elixir’s suitability for real-time communication use cases.
Can you describe a challenging Elixir project you worked on? How did you ensure scalability and fault tolerance?
This question evaluates a candidate’s practical experience, problem-solving approach, and familiarity with advanced topics like distributed systems. It also reveals their ability to align technical solutions with project and pricing constraints.
Phoenix and Ecto are typical Elixir dependencies when building a high-availability (HA) web application. If that’s the stack the candidate mentions, they should be able to talk about aspects like:
- Using Phoenix’s built-in publisher-subscriber system,
Phoenix.PubSub, for real-time updates and Ecto for calls to an SQL database. The choice of SQL database and its own scalability and fault-tolerance challenges can provide an excellent follow-up discussion.
- Deploying to AWS, Azure, GCP, or another cloud provider.
- Working with DevOps tools like Docker to simplify deployment and possibly Kubernetes (K8s) to orchestrate distributed application containers.
- Implementing self-healing strategies, such as supervision trees and retries, to handle production failures gracefully.
- Whether and how microservices fit into their Elixir project. Their answer may be simply that each Elixir application is already something of a microservice, depending on how the concept is defined.
Even if their stack didn’t include Phoenix and Ecto, the last four points can still be relevant discussion starters.
How would you design an API for a real-time chat application using Phoenix?
A strong candidate will provide a clear architectural outline with several key features. Real-time apps often include non-real-time components — in this case, examples include fetching previous chat history and user profile data. So the candidate’s architecture should include not only Phoenix Channels and Presence for real-time communication but also either a REST or GraphQL API for data that changes less often.
Their answer should include using a suitable database (such as PostgreSQL) to store messages and Ecto to query them. Likewise, they’d be remiss to leave out measures like authentication and rate-limiting, which are critical to security and performance.
When asked, a candidate should be able to walk you through how their architecture would handle scenarios like disconnections or partial failures.
Lastly, if your role will have any DevOps overlap, your vetting process should include questions about Docker and any specific cloud providers they’ll be expected to work with, like AWS, GCP, or Azure.
Why Do Companies Hire Elixir Developers?
Elixir developers create high-performance, scalable, fault-tolerant applications, from real-time messaging platforms to back ends hosting complex APIs. Frameworks like Phoenix and Nerves, and Erlang-based tools like OTP remain the basis for truly robust Elixir applications that even hypergrowth companies can be confident in. And with projects like Numerical Elixir (Nx) fueling the language’s ML capabilities, its ecosystem is set to meet the modern needs of companies looking for AI to enhance the features of their software.
With this guide’s coverage of what distinguishes top Elixir developers and how to understand Elixir project requirements, you’re ready to tailor your hiring process toward finding your ideal candidate. Whether you’re a startup seeking rapid development or an enterprise optimizing for scalability, hiring Elixir developers can provide the strategic edge your company needs for short- and long-term success.
