Job description template

Kotlin Developer

We’re hiring a mid-level Kotlin Developer to design, build, and maintain reliable backend services and integrations. You’ll work independently on well-defined work, collaborate with the team to deliver changes end-to-end, and improve system quality over time.

Responsibilities

Develop and maintain backend services in Kotlin, focusing on correctness, performance, and maintainability
Implement and consume APIs and integrations, including validation, error handling, and backward-compatible changes
Design and evolve application data models and persistence layers with appropriate indexing and query patterns
Write and maintain automated tests to ensure safe releases and reduce regressions
Diagnose production issues, perform root-cause analysis, and implement fixes with clear documentation
Improve code quality through refactoring, reviews, and adherence to engineering standards
Collaborate with product and engineering peers to translate requirements into technical solutions

Must-have qualifications

Hands-on Kotlin backend development (services, APIs, and data access)
Strong experience with API design and integration practices (versioning, validation, error handling)
Proven ability to build reliable persistence/data access layers (SQL/ORM patterns, performance awareness)
Hands-on production experience with automated testing (unit/integration) and quality practices
Ability to troubleshoot and resolve production issues using logs/metrics/traces and root-cause analysis

Nice to have

Experience with JVM observability tooling (logging/metrics/tracing) in production
Experience with event-driven or asynchronous systems (queues/streams) using JVM ecosystems
Familiarity with CI/CD workflows and release practices for backend services

What success looks like in 12 months

Ship backend features reliably with low regression risk
Reduce production instability through faster diagnosis and fixes
Improve API quality and compatibility for ongoing development
Strengthen testing coverage for key service paths
Enhance data access performance and correctness

Logistics

Full-time (40 hours a week), remote from Latin America.
Working hours overlap with US business hours.

About the company

[About your company: what you build, your stage and team size]

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Interview scorecard

Score every candidate against the same bar

Deliver and maintain high-quality Kotlin backend services that are reliable in production and evolve safely over time.

Outcomes to measure

What this hire should deliver in the first year. Replace [N] with your own targets.

Ship backend features reliably with low regression risk. Measure: deliver [N] production features with no more than [X]% causing customer-impacting defects
Reduce production instability through faster diagnosis and fixes. Measure: reduce incident frequency by [X]% and reduce mean time to resolution by [X]%
Improve API quality and compatibility for ongoing development. Measure: maintain successful API compatibility with [X]% of breaking changes avoided or mitigated via versioning and validation
Strengthen testing coverage for key service paths. Measure: increase automated test coverage for critical modules by [X]% (or add [N] integration/unit tests) without increasing flaky test rate
Enhance data access performance and correctness. Measure: reduce data-related performance regressions by [X]% and improve slow query performance by [X]% for targeted endpoints

Competencies and weights

What to evaluate, how much it counts and what a strong answer looks like.

Kotlin Backend Delivery · 24%
Core responsibility is building backend services independently using Kotlin best practices. Evaluated in Round 1.

Weak: Writes Kotlin code that compiles but lacks clear structure, reuse, or correctness checks; changes are hard to review or maintain.
Meets the bar: Implements backend features in Kotlin with readable structure, appropriate abstractions, and correct behavior with tests.
Strong: Designs and implements maintainable Kotlin services with clear boundaries, strong error handling, and performance-aware code that stays stable after release.

API Design and Integration · 18%
APIs and integrations drive product functionality and must remain compatible and resilient. Evaluated in Round 2.

Weak: Breaks client compatibility or handles failures inconsistently; validation and error responses are unclear or incomplete.
Meets the bar: Designs/updates APIs with versioning strategy, input validation, and consistent error mapping; can explain tradeoffs.
Strong: Delivers API changes with strong compatibility guarantees, robust validation, and predictable error semantics under real-world failure modes.

Production Debugging · 18%
Must independently troubleshoot production incidents and implement lasting fixes. Evaluated in Round 1.

Weak: Relies on guesswork; struggles to connect symptoms to root cause; fixes do not address contributing factors.
Meets the bar: Uses logs/metrics/traces to narrow down issues; performs root-cause analysis and implements verified fixes.
Strong: Leads structured incident diagnosis, validates impact, prevents recurrence with targeted changes, and documents lessons learned.

Persistence and Performance · 16%
Reliable data access and performance are essential for backend systems. Evaluated in Round 2.

Weak: Implements data access that causes inefficient queries or incorrect results; struggles to reason about indexing or query patterns.
Meets the bar: Builds persistence/data access layers with correct queries and appropriate patterns; identifies and addresses obvious performance issues.
Strong: Proactively optimizes data access using query analysis, indexing strategy, and careful transaction boundaries while ensuring correctness.

Testing and Quality · 15%
Automated tests reduce regressions and enable safe, independent delivery. Evaluated in Round 3.

Weak: Adds minimal or brittle tests; cannot describe how tests catch regressions or prevent flaky failures.
Meets the bar: Creates useful unit/integration tests for critical paths; keeps tests reliable and maintains them through changes.
Strong: Builds a thoughtful test strategy with clear coverage for risk areas and uses test results to drive quality improvements over time.

Independent Execution · 9%
Mid-level scope requires working independently on well-defined work. Evaluated in Round 3.

Weak: Needs frequent guidance for basic milestones; unclear ownership or incomplete delivery.
Meets the bar: Plans and executes within a defined scope; communicates progress and risks clearly and completes deliverables.
Strong: Takes end-to-end ownership, anticipates blockers, coordinates with others when needed, and delivers predictably.

Interview questions

Questions for every interview round

Each round has an owner, a time box and questions that test the competencies above.

Round 1: Backend Kotlin + Production Debugging
Engineering Lead · 60 min

Tell me about a Kotlin backend feature you shipped end-to-end. How did you structure the code and ensure correctness?
Describe a production incident you investigated. What signals did you use (logs/metrics/traces), how did you form hypotheses, and what was the root cause?
Give an example where you improved a failing workflow or reliability issue. What change did you make and how did you verify it?

Round 2: API + Persistence/Performance
Senior Backend Engineer · 60 min

Walk through an API you designed or changed. How did you handle backward compatibility, validation, and error responses?
Describe a time you optimized database performance in a backend service. What was slow, what did you measure, and what fix improved it?
How do you think about transaction boundaries and consistency when implementing data access in Kotlin services?

Round 3: Testing Strategy + Independent Execution
Staff/Principal Engineer · 60 min

Explain your approach to automated testing for backend services. How do you decide what to cover with unit vs integration tests?
Tell me about a time a test strategy prevented a regression. What did the failing test show and what did you change afterward?
Describe how you work independently on a well-defined task. How do you plan, get unblocked, and communicate status and risks?

Red flags to watch for

Cannot provide a concrete example of diagnosing and resolving a production issue with a clear root cause and verification step
Regularly delivers API changes that break clients or lacks a consistent strategy for validation and error handling
Relies on manual testing for critical backend paths or produces flaky/brittle automated tests that erode confidence
Shows limited understanding of database query performance and transaction/consistency implications in backend services

How much does it cost to hire a Kotlin Developer in Latin America?

In 2026, a senior Kotlin Developer in Latin America costs $6,625 to $7,625 a month all-in, versus $14,625 in the US: up to 55% less. Mid-level starts at $4,375.

Country

Mid-level

Senior

Argentina

$4,375

$6,625

Brazil

$4,875

$7,375

Colombia

$4,375

$6,625

Mexico

$5,125

$7,625

United States

$11,875

$14,625

Monthly cost in USD, all-in: the talent's salary plus Teilur's flat 20% fee, from our 2026 rates. The United States row shows what the same role typically costs there.

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Frequently asked questions

What does a Kotlin Developer do?

Typical responsibilities include: develop and maintain backend services in Kotlin, focusing on correctness, performance, and maintainability; implement and consume APIs and integrations, including validation, error handling, and backward-compatible changes; design and evolve application data models and persistence layers with appropriate indexing and query patterns. The full list is in the template above.

How much does it cost to hire a Kotlin Developer in Latin America?

In 2026, a senior Kotlin Developer in Latin America costs $6,625 to $7,625 a month all-in, versus $14,625 in the US: up to 55% less. Mid-level starts at $4,375.

Can I customize this Kotlin Developer job description?

Yes. Teilur's free Job Description & Scorecard Generator rewrites it for your stack, seniority, time zone and hiring urgency in about 15 seconds. No sign-up needed.

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Kotlin Developer Job Description Template