Tips and Interview Questions to Hire the Right Clojure Developer
Hiring & recruiting developers

How to Hire a Clojure Developer – A Comprehensive Guide 

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Ihor Shcherbinin
VP of Recruiting at DistantJob - - - 3 min. to read

With a 12% increase in Clojure development in the past year, there has also been a rise in the demand for Clojure experts. This increase is a nod to Clojure’s efficiency and versatility, making it a sought-after skill in the web development sector. When hiring a Clojure developer, it’s crucial to understand not just their coding skills but also their potential to effectively communicate, collaborate, and adapt within your current team.

In this guide, we’ll cut straight to the essentials of hiring a Clojure developer in 2024, addressing the skills you should seek and interview questions you should ask to find the right talent for your business.

5 Simple Steps to Successfully Hire a Clojure Developer 

Successfully hiring a Clojure developer involves several key steps that go beyond assessing technical skills. You should start with:

1. Identify the Skill Set Your Team Needs 

When hiring a Clojure specialist, it’s important to look for certain skills and qualities that are specific to this language. Here are some of the key skills and qualifications to look for in Clojure developers: 

  • Strong functional programming skills: Clojure is a functional programming language, so the developer must have a deep understanding of functional programming concepts.
  • Experience with Java Virtual Machine (JVM): Since Clojure runs on the JVM, knowledge of Java and JVM is important. This includes understanding how to optimize performance and troubleshoot issues that may arise in a JVM environment.
  • Database Skills: Understanding various database technologies (like SQL, NoSQL, Datomic) and how to integrate them with Clojure applications is important.
  • Experience with concurrency: Clojure is designed to handle concurrency, so the developer should be familiar with concurrency and multithreading.
  • Familiarity with the Clojure ecosystem: The Clojure ecosystem includes a number of libraries and frameworks. Look for developers who are familiar with these tools and have experience working with them. Especially the case with libraries and frameworks that your development team already uses.
  • Understanding of data structures and algorithms: Clojure places a strong emphasis on data structures and algorithms, so make sure that the developer has a solid understanding of these concepts.
  • Familiarity with web development: This is highly dependent on your company’s use case, but many Clojure developers work on web applications, so it is important to look for developers who have experience with web development frameworks.
  • Problem-solving skills: Clojure is a language that emphasizes elegant solutions to complex problems, so it is important to look for developers who are creative problem-solvers.
  • Good communication skills: As with any development role, good communication skills are essential. Look for developers who are able to communicate their ideas clearly and work effectively with team members.

When it comes to qualifications, while a formal degree in computer science or a related field is often beneficial, practical experience and a demonstrated track record in Clojure development can be equally valuable. To accurately assess this, ensure you conduct a thorough review of the candidate’s portfolio and implement a comprehensive interview process that includes practical skill testing.

2. Craft the Perfect job description for a Clojure Role

Job descriptions can highly influence the type of professionals you attract. This is why we always advise you to be very specific about the role. Don’t make generic descriptions or add job titles like “Clojure Guru.”This, rather than attracting candidates, ends up confusing them.

These are the 10 points you should always keep in mind when crafting a Clojure job description:

  1. Job Title Clarity: Start with a clear and precise job title that showcases the role and the level of expertise. Instead of just “Clojure Developer,” be more specific, add “Senior Clojure Developer” or “Senior Cloud Data Engineer.”
  2. Company Introduction: Briefly introduce your company. Highlight your culture, values, and any other aspect that makes your company an attractive place to work. 
  3. Role Overview: Provide a brief yet specific overview of the role. Explain how the position fits into the broader team and company objectives. Be clear about whether the role is for front-end, back-end, full-stack, or a specialized area within Clojure development.
  4. Key Responsibilities:
  • Enumerate the main responsibilities.
  • Include specifics like developing scalable web applications, maintaining existing codebases, collaborating with cross-functional teams, or contributing to open-source projects.
  • Mention if the role involves mentoring junior developers or leading projects.
  1. Required Skills and Qualifications:
  • List essential skills, such as proficiency in Clojure and ClojureScript, understanding of JVM, experience with functional programming, etc.
  • Include qualifications like a degree in Computer Science (if applicable) or equivalent experience.
  • Specify the number of years of experience required.

Desired Skills:

  • Include additional skills that would be advantageous but not mandatory, such as familiarity with specific frameworks, database experience, or front-end technologies.
  1. Cultural Fit:
  • Describe the type of individual who would succeed not just in the role but also in your company culture.
  • Mention soft skills like problem-solving, team collaboration, or a passion for continuous learning.
  1. Benefits and Perks:
  • Detail the benefits and perks of working at your company, like flexible working hours, health insurance, professional development opportunities, or unique company culture aspects.
  1. Application Process (Optional):
  • Explain the steps of the application process clearly.
  • Include information on any coding tests, interviews, or portfolio reviews.
  1. Equal Opportunity Statement: Conclude with an equal opportunity employer statement. This shows your commitment to diversity and inclusivity.
  2. Bonus: You can also highlight any other aspect relevant to the position. For example, if advanced English is required, if the position sponsors visas, etc. 

So, how does this look on a real-life Clojure job description? Here’s an example: 

Job Title: Senior Clojure Developer (Remote Position) 

About Us: At TechInnovate, we’re not just a leading software development company; we’re a hub of innovation and creativity. Recognized for our cutting-edge solutions and dynamic work culture, we’re dedicated to pushing boundaries in the tech world. Join us and be a part of a team that values ingenuity, collaboration, and making a real impact.

Role Overview: We are seeking a seasoned Senior Clojure Developer to join our forward-thinking development team. In this role, you’ll be instrumental in designing and implementing robust, scalable web applications. You’ll play a key role in driving our projects from conception to deployment, working closely with cross-functional teams to deliver innovative software solutions that align with our strategic objectives.

Key Responsibilities:

  • Develop and maintain high-quality, scalable, and innovative Clojure-based applications.
  • Lead the design and implementation of new features and functionalities.
  • Collaborate with product managers, UX/UI designers, and other developers to ensure seamless, high-quality delivery.
  • Provide technical leadership and mentorship to junior developers.
  • Contribute to continuous improvement of our software practices and processes.

Required Skills and Qualifications:

  • At least 5 years of experience in software development, with a focus on Clojure and ClojureScript.
  • Strong understanding of the Java Virtual Machine (JVM) and its optimizations.
  • Expertise in functional programming and software design patterns.
  • Bachelor’s degree in Computer Science or a related field or equivalent experience.

Desired Skills:

  • Experience with web development frameworks such as Ring, Compojure, or Reagent.
  • Familiarity with database technologies (SQL, NoSQL, Datomic).

Benefits and Perks:

  • Competitive salary and comprehensive health benefits.
  • Flexible working hours.
  • Fully remote position. 
  • Generous paid time off and a commitment to work-life balance.

Application Process: Interested candidates should submit a resume and a portfolio of relevant work. Shortlisted candidates will be invited to a coding test followed by an interview process.

Equal Opportunity Employer: Our company is proud to be an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees.

3. Where to Hire Clojure Developers? Explore Different Hiring Alternatives

For specialized roles, hiring is not as easy as posting a job ad and waiting for applicants. When it comes to hiring Clojure engineers, it’s important to know where to look. Here are some of the best places to start your search:

1. Remote Recruitment Agencies

As we’ve shown above, the cost of hiring a Clojure developer greatly depends on where they are located. So, by working with remote recruitment agencies, you expand your global reach, gaining access to a diverse pool of talent. Additionally, IT staffing agencies often focus on other aspects of hiring. For instance, at DistantJob, besides headhunting and evaluating, we also focus on matching the specific technical and cultural needs of your project with the right candidate.

2. Freelancing Platforms

If you’re looking for Clojure specialists for a short-term project, then freelancers are a great option. Websites like Upwork and Toptal are known for finding freelance developers fast. These types of platforms allow you to review portfolios, read client feedback and easily find professionals with the skills you need. 

3. Online Tech Communities 

Online tech communities often offer projects and discussions where you can take a glance at a developer’s professionalism and skill set. Platforms like GitHub and Stack Overflow often have Clojure developers involved in projects, giving you insights into their expertise and problem-solving abilities.

4. Tech Job Boards

Websites such as Dice, Crunchboard, and Jobspresso specialize in job listings for technology roles. On these platforms, you have the option to post your own job advertisements or browse through the profiles of professionals with expertise in Clojure.

5. Clojure Meetups 

While attending Meetups can be a more cost and time-consuming strategy, it’s still a good alternative to get to experience first-hand the expertise and experience of Clojure developers. Some meetups, like the Clojure Berlin meetup, actively encourage companies to advertise their job.

4. Conduct Thorough Evaluations

The best way of evaluating a candidate’s Clojure proficiency is through evaluations. However, rather than generic online tests make sure that you’re evaluating the skills your team needs. This may include coding exercises, problem-solving challenges or even reviewing their past projects related to Clojure development. 

 Beyond technical skills, we always advise to also assess how well the candidate aligns with your company culture and values. This factor depends mostly if you’re looking to establish a long-term relationship. Make sure to also include interviews that delve into their collaboration style, communication skills, and ability to work within a team. 

5. Build an Onboarding Process 

After identifying and selecting the ideal candidate through the interview process, prioritize a seamless onboarding experience. Furnish comprehensive documentation to deepen their understanding of the company and its processes. 

Facilitate a smooth transition by introducing them to key team members and providing an insightful overview of company policies and practices. Additionally, during their initial weeks remember to set clear expectations and milestones to help them integrate seamlessly into the team.

How Much Does it Cost to Hire Clojure Developers? 

Hiring a Clojure developer in the US costs around $125.000/year, depending on the specialization. In addition, pay rates vary according to the developer’s location, year of experience and set of skills. Without impacting the last two factors, you can save money by hiring remotely outside the US.

Here are some values for Clojure developer salaries we’ve researched using values sourced from Talent.com, Glassdoor and DeveloperSalary.com:

CountrySalary per yearSalary per monthSalary per hour
USA$125,320$10,443$65
Mexico$48,168$4,014$25
Brazil$41,232$3,436$21
Poland$47,172$3,931$25

9 Clojure Interview Questions to Ask Your Dev Candidate

To ensure you’re bringing the right talent on board, here are key Clojure interview questions to ask your developer candidates: 

1. Coding tasks

If you want to hire a Clojure developer, you need to make sure that they aren’t just an expert at theoretical questions, but that they also know how to do some common coding tasks.

2. Write a recursive function that generates every permutation of an input string and returns them as a set

With this question from Interview Cake, your potential developer doesn’t need to spend their time focusing on efficiency. Instead, it’s meant to see if they can write this code with Clojure. Assume each character in the input string is unique, and the function is allowed to have loops, as long as it is also recursive.

Let’s take a look an example solution to this code:

(defn- remaining-subs [s idx]

(str (subs s 0 idx)

(subs s (inc idx) (count s))))

(defn permutations

"O(n!) time solution - recursively computing permutations."

[s]

(if (<= (count s) 1)

#[s]

(reduce-kv

(fn [permutations-so-far idx char]

(->> (permutations (remaining-subs s idx))

(map (partial str char))

(into permutations-so-far)))

#{}

(vec s))))

Keep in mind that this is just one solution, but not the only possible solution as there are different ways of accomplishing the question. If you don’t want to worry about trying to interview for a developer in a language you don’t know or understand, let us find you a highly-vetted expert so you can get straight to work.

3. There is a pre-existing function rand5() that generates a random integer from 1 to 5. Use it to write the function rand7() that generates a random integer from 1 to 7.

This commonly asked interview question is meant to simulate a 5-sided die and then becoming a 7-sided die. It makes sure that your developer knows how to write code correctly in the language of your choice, that they have substantial logic skills, and that they can incorporate pre-existing functions, perhaps created by another team member or before they came on-board, to the desired result.

The first method already returns each integer with equal probability, and rand7() must do the same.

Let’s take a look at a sample solution:

(defn- random [floor ceiling]

(+ floor (rand-int (inc (- ceiling floor)))))

(defn- rand5 []

(random 1 5))

(def ^:private rand7-matrix

(->> (range 1 8)

(cycle)

(take 21)

(partition 5 5 (repeat 0))

(mapv vec)))

(defn rand7-with-matrix []

(loop [row (dec (rand5))

column (dec (rand5))]

(if (and (= row 4) (> column 0))

(recur (dec (rand5)) (dec (rand5)))

(get-in rand7-matrix [row column]))))

(defn rand7 []

(loop [rand-a (rand5)

rand-b (rand5)]

(let [out (inc (+ (* (dec rand-a) 5) (dec rand-b)))]

(if (<= out 21)

(inc (mod out 7))

(recur (rand5) (rand5))))))

4. Find the highest product you can get from any three integers in a given list of integers

This coding task is relatively simple, but it confirms that they have a solid grasp of the logic of Clojure as well as how to properly write it.

The input list_of_ints that we’ll use in this given example will always have at least three integers, so your potential coders won’t have to test for this outlier.

(defn- rotation

"Rotates bucket of k length around the bottom and top of arr by idx."

[arr k idx]

(let [top (- (count arr) (- k idx))]

(vec (concat (subvec arr 0 idx)

(subvec arr top)))))

(defn highest-product-of-k

"0(nlgn) time + 0(n + (k + k^2)) space solution."

[k arr]

(if (>= k (count arr))

(reduce * arr)

(->> (range (inc k))

(map (partial rotation (vec (sort arr)) k))

(map (partial reduce *))

(apply max))))

5. Write a Clojure function to parse a JSON string and return a map with keys sorted alphabetically. Discuss the choices made in your implementation.

(def counter (atom 0))

(defn increment-counter [] (swap! counter inc))

(def agent-example (agent 0))

(send agent-example inc)

Atoms provide a way to manage shared, mutable state with safe, atomic updates. Here, counter is an atom that is incremented safely using swap!. Agents are used for asynchronous state changes. agent-example demonstrates an asynchronous increment. 

Atoms are used when synchronous updates are needed, while agents are useful for asynchronous operations.

6. Write a Clojure function to parse a JSON string and return a map with keys sorted alphabetically. Discuss the choices made in your implementation

(require '[clojure.data.json :as json])

(defn parse-and-sort-json [json-str]

(into (sorted-map) (json/read-str json-str)))

This function uses the clojure.data.json library to parse the JSON string. json/read-str converts the JSON string into a Clojure map, and into (sorted-map) then sorts this map by keys. The choice of sorted-map ensures that the keys are automatically sorted in alphabetical order.

7. Explain transducers in Clojure. Provide an example of creating a custom transducer and using it with reduce.”

(defn filter-even [rf]

(fn

([] (rf))

([result] (rf result))

([result input]

(if (even? input)

(rf result input)

result))))

(reduce (filter-even conj) [] [1 2 3 4 5])

Transducers are composable algorithmic transformations. They decouple the process of transforming data from the context of the transformation (e.g., collections, streams). Here, filter-even is a transducer that filters even numbers. It’s used with reduce, applying the conj function only to even numbers.

8. Write a function in Clojure that takes a large dataset and efficiently finds the top N elements. Explain how your solution handles performance considerations

(defn top-n-elements [n data]

(->> data

(sort >)

(take n)))

This function sorts the dataset in descending order and then takes the first N elements. For large datasets, sorting can be a performance bottleneck. One way to optimize this is by using a priority queue or a min-heap, which can handle large data more efficiently, especially when only a small subset of the top elements is needed.

9. Write a Clojure function that takes a list and returns a new list with every second element removed. Explain your approach.

(defn remove-second [lst]

(keep-indexed (fn [idx x] (if (odd? idx) x)) lst))

This function uses keep-indexed, which keeps elements based on their index. The anonymous function (fn [idx x] (if (odd? idx) x)) returns the element x only if its index idx is odd, effectively removing every second element (at even indices, considering 0-based indexing).

10. How would you implement a memoized Fibonacci function in Clojure? Discuss the benefits of memoization in this context.

(def fib

(memoize (fn [n]

(if (or (= n 0) (= n 1))

n

(+ (fib (dec n)) (fib (- n 2)))))))

Memoization stores the results of expensive function calls and returns the cached result when the same inputs occur again. In the case of the Fibonacci sequence, memoization prevents the exponential growth in computation by caching previously computed values.

11. Can you demonstrate how to handle exceptions in Clojure using try/catch? Write a sample code snippet.

(try

(/ 10 0)

(catch ArithmeticException e

(println "Caught an arithmetic exception: " (.getMessage e))))

This code tries to divide 10 by 0, which will throw an ArithmeticException. The catch block captures this exception, and the message is printed out, demonstrating exception handling in Clojure.

Hire Clojure Developers Fast and Easy With DistantJob

Clojure is a coding language that can have great results in your company if used properly. By hiring a Clojure developer, you can blend expertise and innovation to create reliable websites or applications seamlessly.

If you’re looking to hire an expert Clojure developer, then DistantJob can be your partner and find you who you need to complete your projects successfully. We can get you the developers you need and that fit your company in just under two weeks. Interested? Contact us or visit our offices today!

Ihor Shcherbinin

Ihor is the Vice President of Recruiting at DistantJob, a remote IT staffing agency. With over 11 years of experience in the tech recruitment industry, he has established himself as a leading expert in sourcing, vetting and placing top-tier remote developers for North American companies.

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