Certification

Senior Kotlin Developer

This certification is designed for experienced Kotlin developers who work on production systems and make implementation decisions that influence reliability, maintainability, and long-term code quality.

It validates senior-level capability in Kotlin language features, null-safety, object and API design, collections and functional style, coroutines, concurrency control, testing strategy, and application architecture. The emphasis is on using Kotlin thoughtfully in real engineering environments rather than relying on surface-level familiarity with syntax.

Candidates are expected to demonstrate that they can structure Kotlin codebases clearly, model domain logic safely, control side effects, manage asynchronous workflows, and debug issues that emerge in evolving production applications. This includes understanding how Kotlin helps teams build expressive, correct, and maintainable systems under real delivery pressure.

The certification is suitable for developers who already use Kotlin professionally and want to validate that they can deliver robust, scalable, and well-structured applications with senior-level engineering discipline.

Get Certified

What this certification proves

Clear scope for candidates. Clear meaning for reviewers.

Passing result

What a pass confirms

This certificate confirms that the candidate demonstrated senior-level Kotlin development competence in building maintainable application architectures, writing reliable production code, and managing concurrency with sound engineering judgment.

Scope

What the exam validates

Scope includes Kotlin language semantics, null-safety, object-oriented and functional design, collections handling, coroutines, concurrency patterns, API design, testing strategy, debugging, performance awareness, and long-term maintainability decisions.

For reviewers

What someone can verify later

The public certificate page shows the holder name, score, issue date, certificate ID, and current verification status without relying on screenshots.

Share flow

Share one record, not a bundle of files

Use the certificate page as the primary proof. PDF stays available as a convenient copy, but the live page is the canonical record.

Official certificate page

What the verifier will see

Candidate name
Score and pass outcome
Date and certificate ID
Current verification status

Preparation topics

Topics covered by the exam question set.

Use this topic map as a preparation checklist. Questions in this certification are built from these concrete topic areas.

Language Basics

basic syntax
val vs var
type inference
string templates
expressions
control flow

Null Safety

nullable types
safe calls
Elvis operator
smart casts
safe casts
not-null assertion
null transforms

Scope Functions

let
run
with
apply
also
takeIf
takeUnless

Collections and Maps

list operations
map operations
set operations
collection transforms
associateBy
groupBy
partition
any all none

Sequences

lazy sequences
sequence builders
terminal operations
re-evaluation
side effects

Classes and Objects

class properties
primary constructors
secondary constructors
init blocks
visibility modifiers
object declarations
companion objects
anonymous objects

Interfaces and Abstraction

interfaces
default methods
abstract classes
override rules
conflict resolution
constructor state

Properties and Delegates

custom getters
custom setters
backing fields
backing properties
lazy delegate
observable delegate
vetoable delegate
const val
lateinit

Data and Sealed Types

data classes
copy semantics
enum classes
sealed classes
sealed interfaces
data objects
exhaustive when
equality rules
hash contracts

Destructuring

component functions
data destructuring
map entries
lambda destructuring
skipped components
destructured matches

Functions and Inlining

higher-order functions
extension functions
extension properties
local functions
inline functions
crossinline
noinline
non-local returns

Generics and Type System

generic bounds
variance
reified types
type erasure
runtime checks
platform types
Any Unit Nothing

Operators and Infix

operator overloading
assignment operators
comparison operators
invoke operator
contains operator
indexing operators
infix functions
precedence rules

Reflection and Interop

KClass
Java Class
function references
property references
constructor references
bound references
unbound references
@JvmStatic
@JvmField
static bridges

Annotations and Regex

annotation targets
retention policy
use-site targets
annotation arguments
raw strings
regex matching
capture groups
regex replace
input escaping

Coroutines

suspend functions
coroutine builders
coroutine scope
structured concurrency
async await
dispatchers
cancellation
supervisor scope
exception propagation
coroutine context
ThreadLocal context

Flow and State

cold flows
hot flows
flow operators
flowOn
catch boundary
combine zip
latest operators
StateFlow
SharedFlow
state updates
sharing strategies

How the certification works

From voucher purchase to public certificate.

Once the candidate decides to pursue this certification, the path is simple: buy a voucher, exchange it for this certification, complete the exam, and receive the official certificate after a successful result.

Step 01

Buy a voucher for account balance

The candidate tops up voucher balance first. DevCerts does not sell this certification as a direct one-off checkout item.

Step 02

Choose this certification and exchange the voucher

When the candidate is ready, one voucher is consumed and DevCerts opens exam access for this certification.

Step 03

Pass and receive the official certificate page

After a successful valid result is received from Askium, DevCerts issues the certificate, publishes the public verification page, and keeps PDF available as a secondary copy.

Current certificate policy

What this certification page promises today

A certificate is issued only after a successful valid result.
The public verification page is the canonical certificate artifact.
The issued certificate is active and non-expiring in the current MVP.