Updates to Task Difficulty Levels – August 2025
To ensure that our platform accurately reflects the evolving skills and expectations of candidates, we have reviewed and adjusted the difficulty levels of 246 tasks in our library. This update includes:
- 117 Real-life tasks
- 129 Fundamental tasks
We've included the complete list of tasks affected by this update at the end of this message — feel free to review them at your convenience.
Why are we making these changes?
At Codility, we continuously analyze candidate performance data to fine-tune how we classify the difficulty of our tasks. This helps hiring teams select tasks that are best suited for their recruitment goals and candidate profiles. Here’s how we determine the difficulty of our tasks.
What’s changing?
Only the difficulty ratings of the tasks have been updated.
There are no changes to the task content itself — inputs, outputs, scoring, or descriptions remain untouched.
What does this mean for you?
- If you're using these tasks in your tests, their difficulty tag might appear different, but the test behavior remains exactly the same.
- These adjustments aim to more accurately reflect how real candidates perform, giving you better alignment between task labels and actual challenge level.
Full list of changes:
Real-life tasks:
AggregatedPrices to easy
AngularSideMenu to medium
ApacheCamelFiltering to hard
AsynchronousTaskRunner to medium
ReactAutocompleteTypescript to easy
BayesianAbTesting to elementary
BlocStateManagement to medium
BruteForcePassword to easy
ClientSideCaching to easy
ClusteringForImageSegmentation to easy
ConfigurationServer to easy
CustomStringEnumerator to medium
Auroc to elementary
DatabaseTransactionsSimulator to easy
DjangoModels to easy
DjangoShopping to elementary
DjangoZoo to easy
DockerComposeDryConfig to hard
DockerGoMultistage to elementary
DockerNginxAssets to elementary
DockerNodejs to elementary
DotnetConvention to medium
DotnetPagination to medium
DynamicObjectParser to medium
ExtendArrayPrototype to easy
FinancialClustering to medium
FlexboxBlogCard to hard
FoodBasket to elementary
FootballFormation to elementary
GsonParsing to easy
HeaderSecurity to medium
HelmServiceDefinition to easy
Html5SimpleArticle to hard
ImbalancedDataset to easy
InventoryRepository to easy
Iterable to easy
Java8ProductionLineTester to easy
Java8Reconciliation to medium
JsCreatePrototype to elementary
JsLibrary to easy
JsMaxTable to elementary
JsTestValidation to medium
JwtFilter to easy
LaravelBlogRouting to elementary
LazyLoading to medium
LocalstorageService to medium
LoggerTemplateHelper to easy
ManageEntityRelationship to hard
MedicalDataAnalysis to easy
MessyCsv to easy
MongodbArrayAggregation to easy
ReactPagination to easy
PodWebserver to elementary
PopularCourses to easy
Promisify to easy
ReactBugFixing to medium
ReactJavascriptSideMenu to easy
ReactMusicPlayer to easy
ReactStyledComponents to elementary
ReduxChat to elementary
Regression to easy
RequestInterceptors to elementary
RspecController to easy
RxjavaChaining to medium
ServiceHealthCheck to easy
ShellFindFunction to easy
ShoppingCart to medium
SpringAspectOrientedProgramming to hard
SpringDataJpaCrud to hard
SpringHateoasApi to hard
SpringMicrometerCustomMetrics to easy
SpringOrders to easy
SqlalchemyOrm to medium
StatefulService to easy
StringInverter to elementary
StringValidation to elementary
SymfonyController to easy
SymfonyValidation to easy
TensorflowCustomLayer to elementary
VarianceAnalysis to medium
VersionComparator to medium
Vue15Puzzle to easy
VueAutocomplete to easy
VueLoginPage to elementary
VueSideMenu to elementary
WcagColor to easy
AcademicNotes to medium
ActionMailer to medium
BashAccessLog to medium
BashLogTail to hard
BasicApiTests to hard
BuilderPattern to medium
CliApplication to hard
CombiningSamplingMultipleStreams to hard
Compose to hard
CssContentPositions to medium
CssDropDownMenu to medium
CustomLossFunction to medium
DockerComposeBuild to medium
DockerComposeMultipleContainers to medium
Emojify to medium
GesturesTodoApp to medium
InheritanceStrategies to hard
JqueryTable to medium
JsCaptcha to easy
KnnTask to hard
LambdaGeneratePdf to hard
LodashThrottle to medium
ModuleLineIterator to hard
QaPagination to hard
QaJavaSearch to hard
ServerlessFixDeployment to medium
SklearnTransformers to medium
SpringTaskManager to hard
TerraformS3Sqs to medium
TestingCallsToDependency to medium
TextClassification to medium
Fundamental tasks:
BallsInBuckets to hard
BoardRecovery to medium
BreakThePalindrome to easy
CarAssembly to easy
ClosestDigitSwap to hard
CommonDigit to medium
DecreaseFuelConsumption to medium
DeleteDefectiveRows to easy
DivisibleByThree to easy
EqualFractions to easy
EqualSums to medium
ErasePairs to medium
EvenWord to elementary
FourDigitsPath to easy
ArraySlicing to easy
IncreaseMultipliers to medium
IncreaseTheDigits to easy
IntersectingLineChart to medium
LargestPothole to elementary
LongestEvenPath to medium
MakeArrayIncreasing to medium
MaxBiValuedSlice to easy
MaxOddDecomposition to medium
MaxTrailingZeros to medium
MergeNeighbors to medium
MinStackHeightSum to easy
MonthlyBalance to hard
OddPairs to elementary
OneTwoDigits to medium
OptimizingFarthestDifferent to easy
PriceFluctuation to easy
RecyclingTrucks to easy
Rerooting to medium
RoadRoller to easy
Rome to medium
RoomCounter to easy
RotateArrows to medium
SameDigitEnds to easy
SimilarRectangles to hard
SkillTree to easy
SortedLetters to medium
StringCutter to medium
SumOfThree to medium
ThreeLetterSubstring to elementary
TotalWaitingTime to hard
TransformString to easy
TreeExpansion to elementary
UniqueCharacters to medium
WordSplit to easy
AssassinsStealth to hard
Basketballs to hard
DifferentProducts to medium
DigitString to medium
DigitSumReplacement to medium
DigitsSum to medium
DiversityString to medium
EvenPairsOnCycle to medium
FindIntervalInArray to hard
LongestPath to hard
LongestTileSequence to hard
MonitorsDelivery to medium
ReplaceByFive to medium
SameDigitMerge to medium
SmallestDiverseWord to hard
SparseArray to medium
SquareTiles to hard
SumOfThreeTesting to hard
SymmetricGrid to medium
TwoProjects to hard
VideoAngleBrackets to hard
BugfixingBinaryPeriod to easy
BugfixingComputeMinProduct to hard
BugfixingMaxNonnegSliceSum to easy
BugfixingNails to medium
BugfixingRoomCounter to easy
BugfixingFavoriteNumber to medium
BugfixingOppositeNumbers to easy
BugfixingRepeatCounter to hard
BalancedRectangles to easy
BalancedTree to easy
ChoosingNumbers to easy
InterviewScenarioAiPromptwritingLetters to easy
CompanyEmailsVar (Opal variant) to easy
Kfold to easy
DetectSquare to hard
DominoPyramid to medium
DoubleDigitsSum to elementary
LettersGrid to medium
MetroTicketPrice to elementary
OddTwoDigitNumbers to easy
PasswordCheck to hard
TestingComputeMin to elementary
Recipes to elementary
SecurePassword to elementary
StringMisspellingVar (Topaz variant) to medium
StringOcrMatch to easy
TwoDigitHours to easy
VideoAllNumbers to easy
WarmNights to elementary
AlternatingSigns to easy
BackAndForth to hard
CheckRectangle to medium
CompanyEmailsVar (Topaz variant) to medium
ConvertToPalindrome to medium
CoverPoints to hard
EqualizeHeadsTails to easy
FileListVar (Jade variant) to hard
FileListVar (Opal variant) to medium
GenerateDigitString to hard
GymEntrances to easy
HighestCardSet to hard
IncreaseTheNumber to easy
LastZero to easy
LatestDate to medium
LeadTheCleaningRobot to hard
LessThanThreeDigits to easy
SubmatrixSum to hard
UpsideDown to easy
VideoCheckRectangle to medium
DevThinkingMcq to easy
SticksTesting to hard
MysqlAccessUser to elementary
SqlTheater to elementary
SqlCompetition to easy
SqlPhonecalls to elementary
SqlRecruitment to elementary
SqlVideoAssignTaskDifficulty to elementary
SqlWarehouse to easy
SqlInterflightCities to medium
This change only affects customers creating new tests.
If you have previously used one of the listed tasks, we ask that you be mindful that their difficulty level may have changed. The signal that you have been receiving from tests using the given tasks will remain the same.
If you have questions about our task library or need help with your tests, reach out to your Customer Success Manager or support@codility.com