Codility on Reddit: what 429 threads say and get wrong_

We are Codility, the company behind the platform, and this is our analysis. Every quote below links to the thread it came from. Hiring teams can go straight to what hiring teams get wrong.

What is Codility?

Codility is a skills assessment platform. Companies use it in 4 ways: to hire engineers, to hire for any other role, to assess the engineers they already employ, and to assess how well their other employees use AI. Screen and Interview cover hiring, Skills Intelligence covers current employees, and AI for Business is the name for assessing AI skills outside engineering.

A candidate meets Codility through an employer. The employer sends an invite link, and the test behind it contains tasks the employer picked from our library or wrote itself. The employer also sets the time limit, the pass mark, the integrity settings and whether AI help is allowed. The candidate gets a score, and the employer decides what happens next.

When a Reddit thread describes “the Codility test”, it is describing one employer’s choices on the platform.

How we reviewed what Reddit says about Codility

We collected the Reddit threads that mentioned Codility between 9 October 2023 and 8 October 2026 and that our searches could find. We read all 429 of them and assigned each one to a single main topic. We read every post in full, plus the comments under the most discussed threads.

Reddit has no star rating, so this review reports the topics people discuss. The chart below shows how the 429 threads split.

What do Reddit threads about Codility discuss?

Share of 429 threads

What's on the test, for one employer

45.5%

Ghosted or waiting after the test

8.6%

Scores and hidden test cases

7.9%

Live interviews on Codility

7.7%

Cheating, AI use and proctoring

7.2%

Buyer evaluation and pricing

5.8%

Invite and link problems

3.7%

Too many rounds, one-way tests

3.3%

Passing mentions of Codility

2.8%

Practice resources

2.8%

Editor friction

2.6%

"Doesn't measure real work"

2.1%

The 5 largest topics are test preparation, silence after the test, scoring, live interviews, and AI use.

What candidates get wrong about Codility on Reddit

Most candidate threads treat the test they received as “the Codility test”, but the employer who sent it chose every task, time limit, integrity setting and pass mark in it. 2 candidates applying to 2 employers can sit 2 very different tests on the same platform.

Is a Codility test just LeetCode?

Some Codility tests are algorithm problems, and many are not. The threads describe React components, API endpoints, SQL, data pipelines, debugging tasks and system design, depending on the role and the employer.

LeetCode is still the most common comparison: it comes up in 118 threads, more than any other product name. That count reflects how candidates prepare. The examples above show the tasks employers send.

Frontend engineer assessment Task 1 of 3 timer62 min left typescriptexpand_more Submit task

Task 1 Tag chips Build a component that shows a list of tags as chips. Show at most limit chips and replace the rest with one +N chip.

React TypeScript Medium

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export function TagChips({ tags, limit }: Props) {

const visible = tags.slice(0, limit);

const hidden = tags.length – visible.length;

return (

<ul className=“chips”>

{visible.map(t => <li key={t}>{t}</li>)}

{hidden > 0 && <li>+{hidden}</li>}

</ul>

);

}

Example tests Console play_arrowRun tests

check_circleexample_1: renders 3 chipsPassed

check_circleexample_2: limit 2 of 3 shows +1Passed

infoRun tests checks the example tests only. Hidden tests run after you submit.

How does Codility score a test, and does anyone read the code?

Codility scores correctness and performance against hidden test cases, so passing the visible examples does not mean passing the task. Whether a person then reads the code is the employer’s decision. There is no universal Codility pass mark: each employer sets its own.

The hidden tests cause the most frustration.

Accounts from both sides of the process describe something gentler than automatic rejection. A former program candidate on r/codingbootcamp said the interviewers “were fine with my work being somewhere between pseudo-code and functional code.” A hiring manager on r/cscareerquestions wrote “I try to be quite generous in letting candidates through it into an interview.”

Candidate report · Backend engineer screen Candidate 0412

Completed

38% Total score

Task 2 · Rate limiter python Correctness 40% · Performance 0%

Test Type Result exampleExampleOK empty_inputCorrectnessOK burst_over_limitCorrectnessWrong answer clock_skewCorrectnessWrong answer large_input_1e6PerformanceTimeout

Submitted code open_in_fullView code

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def allow(log, t):

log.append(t)

recent = [x for x in log

if t – x < 1]

return len(recent) <= 10

Can Codility see my screen or record my camera?

Only if the employer switches it on. Proctoring on Codility is disabled by default, and each employer chooses which signals to turn on, so one candidate is recorded and the next is not. Codility’s help center confirms both points: recruiters decide when to turn proctoring on, and Photo ID verification runs only when the employer activates it.

The threads show the range.

Backend engineer screen

Assessment settings

Details Tasks and integrity Invite

Tasks

Time limit 90min

AI Assistance

task_1REST APIOff

task_2SQLOn

Proctoring

infoProctoring is off by default.

videocamCamera

screen_recordScreen recording

badgePhoto ID verification

desktop_windowsRequire Codility Desktop App

Can I use AI or Google during a Codility test?

It depends on the employer’s rules for that test. Some employers switch on an AI Assistant inside the test, others allow AI and web searches, and others allow neither.

In the second and third cases, the rejection followed a rule nobody wrote down.

Does Codility check for cheating?

Yes. Codility checks every new solution against earlier submissions and known leaks, and it reports the risk signals the employer has turned on. The employer sees an integrity risk level with the evidence behind it, and a person at the employer decides how to read that evidence.

One campus candidate on r/PlacementsPrep said the employer “used some kind of signals to detect cheating and caught the ones who did.” The opposite claim, that Codility doesn’t proctor closely, mostly comes from communities built around paid overlay apps, tools that sit on top of the test and hide from screen sharing.

Employers can also require the Codility Desktop App for a test. The Desktop App is designed to surface overlay apps that screen sharing cannot capture, and a reviewer at the employer sees what it surfaces and makes the decision.

shield Integrity Medium risk

NoneLowMediumHigh

difference

Similarity checkTask 2 is similar to 1 earlier submission

Similarity detected

badge

Photo ID verificationID matched the candidate

Verified

desktop_windows

Codility Desktop AppNo overlay apps surfaced

None found

person_check A reviewer at your company makes the decision. No AI is used to produce the risk level. Review evidence

We cover the approach in more depth in Preventing cheating in coding assessments and in why AI code detection is the wrong hiring question.

Why didn’t I hear back after my Codility test?

The employer decides who moves forward and reviews results on its own schedule. Silence after the test is the second most discussed topic in the data set, and 25 of its 37 threads come from early-career candidates.

“You don’t get feedback. If you get an interview you passed, if you don’t you failed.”

An apprenticeship applicant on r/PlacementsPrep received an automated rejection saying the employer had been “unable to reach you regarding next steps”, while other applicants got a second test the next day.

What hiring teams get wrong about Codility on Reddit

Hiring teams who read Reddit to judge Codility are mostly reading candidates’ reactions to other employers’ test design. Only 14 of the 429 threads come from buyers. The rest tell you more about how to run an assessment than about the platform.

Do candidates hate Codility?

No. The complaints in these threads target when the test arrives and how many rounds follow it, and they name Codility alongside HackerRank and HireVue.

Is Codility only an online test?

No. 33 of the 429 threads describe employers running live coding and design interviews on Codility.

A candidate on r/microsoft described the first stage as “a technical coding interview with a technical expert on Codility platform.” An internship invite quoted on r/GeneralMotors said “The interview will be using Codility for the coding portion and Miro for whiteboarding/diagramming.” A data science candidate said the live session “mostly concentrated on the design part and not the correctness”, in a reply on r/microsoft.

Does a low average score mean weak candidates?

A cohort that clusters at 25 to 40% usually points to tasks that are too hard or too long for the role, and the hiring team can change that.

Can AI tools beat a Codility test, and does Codility ban AI?

Codility does not ban AI. Some employers switch on an AI Assistant inside the test on purpose, and the overlay apps sold as working “on Codility” are what the Desktop App described above is designed to surface.

The AI conversation is growing fast. 9 of the 31 threads on AI and cheating are vendor posts: communities built around overlay apps, and startups pitching their own assessment tools. One founder pitching their own product on r/SaaS claimed that “tools like HackerRank/Codility treat AI as cheating.” In the same period, candidates at 4 different employers reported tests where AI was allowed.

How fast is the Reddit conversation about AI use on Codility growing?

Threads about AI use, cheating and proctoring, per year

Is Codility expensive, developer-only and priced only through sales?

Codility publishes the price of two self-serve plans, so a team can check the cost against its own hiring volume. Codility also assesses AI skills in business roles as well as engineering, so two of the three claims are out of date.

On 13 October 2026, Codility’s pricing page listed Starter at $1,200 a year for up to 120 invite credits, Scale at $6,000 a year for up to 300 invite credits, and a Custom plan by quote. Starter and Scale are self-serve, and invite credits are used in Screen or Interview. On cost, the useful comparison is the plan price against the engineering interview hours a screen saves. AI for Business assesses AI skills in business roles inside Screen or Skills Intelligence.

A competitor wrote 7 of the 25 buyer-evaluation threads: Hirevire posted them in its own subreddit. One r/Hirevire post quotes Codility at “$1,200-6,000/year”, and another lists “technical roles only” as a con. The price range is right. The role coverage is not.

The 11 misreadings at a glance

Summary: what Reddit gets right about Codility, and what it gets wrong

Reddit is right on 4 points, and 3 of them are criticisms.

Codility pros and cons

These are drawn from the Reddit threads and from reviews on G2 and Capterra, and they describe the platform as candidates and hiring teams report it.

Is Codility worth it?

Codility helps hiring teams hold one consistent, defensible standard across every team and hundreds of candidates, so engineers spend fewer hours interviewing candidates who were never going to pass.

In the Reddit evidence, 3 things decide a candidate’s experience: the tasks you choose, your AI rule, and the information you give candidates before the test. You set the first 2 in Codility for each test, and the invite covers the third.

What we do about each misreading

AI is the fastest-growing topic in the threads, so it comes first.

Live interview · Backend engineer auto_awesomeAI Assistance on 00:24:10

JKAM

End interview

Explorer

▾ src

rate_limiter.py

store.py

▾ tests

test_limiter.py

README.md

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from collections import deque

class RateLimiter:

def __init__(self, limit=10):

self.limit, self.log = limit, deque()

def allow(self, t):

while self.log and t – self.log[0] >= 1:

self.log.popleft()

Terminal

$ pytest -q

4 passed in 0.31s

smart_toyClaude CodeAgent

Use a sliding window so more than 10 requests in one second are rejected.

Updated allow() to keep timestamps in a deque and drop entries older than one second. Run the tests to check.

historySaved to the candidate record as AI activity

Claude Code runs on Custom plans. The agentic AI Copilot is included in Starter and Scale. Customers choose whether their data is hosted in the US or the EU.

Early-career hiring is where most of the ghosting threads come from, and it is a segment that needs proctoring. We describe how employers assess thousands of graduates fairly in Early careers hiring at scale. If you are comparing vendors, our Codility alternatives page sets out where other tools fit better.

What to tell candidates before they take your Codility test

Tell candidates 6 things about the test in the invite. The candidate threads above guess at each of them.

1. 01The task types and the programming languages allowed.
2. 02The time limit.
3. 03Whether AI or web searches are allowed, task by task if the rule differs.
4. 04The recording settings, including whether the camera or the screen is recorded.
5. 05Whether a person reads the code, or only the score is used.
6. 06When candidates will hear back, including if they don’t advance.

You set the tasks, the time limit, the AI rule and the recording settings in Codility when you create the test. Writing all 6 points into the invite takes one paragraph and answers the questions candidates most often take to Reddit.

Invite candidates Backend engineer screen Preview sendSend invite

SubjectYour Codility assessment for Backend engineer

Message

Hi Sam, here is what to expect from the test: Tasks: one REST API task and one SQL task. Use python, java or go. Time limit: 90 minutes. AI: the AI Assistant is on for the SQL task only. Web searches are fine. Recording: no camera or screen recording. Review: an engineer on the team reads your code. Results: you will hear from us within 5 working days, either way.

Test settings

TasksREST API · SQL

Time limit90 min

AI AssistanceTask 2 only

ProctoringOff

Codility reviews on other review sites

Hiring teams who review Codility on G2, Capterra and Software Advice rate it 4.6 / 5. These reviews come from people who buy and run the platform.

What doesn’t count as a Codility review

Glassdoor ranks for “codility reviews”, but its reviews rate Codility as an employer, so we left them out.

Frequently asked questions about Codility

How difficult is the Codility test?

The difficulty depends on the employer. Each employer picks the tasks, the time limit and the pass mark, so one Codility test can be a short algorithm task and another a multi-hour build task. Hidden test cases for edge cases and performance make the score stricter than the visible examples suggest.

Does Codility record my camera or screen?

Only if the employer turns it on. Proctoring on Codility is disabled by default, and each employer chooses which signals to enable, such as camera, screen recording or photo ID.

Does Codility check for cheating?

Yes. Codility checks every new solution against earlier submissions and gives the employer an integrity risk level with the evidence behind it. Employers can also require the Codility Desktop App, which is designed to surface overlay apps hidden from screen sharing. A person at the employer reviews the evidence and makes the decision.

Can I use Google or AI during a Codility test?

Only if the employer allows it for that test. Some employers switch on the AI Assistant inside the test, some allow AI and web searches, and some allow neither. If the invite doesn’t say, ask the recruiter in writing before you start.

Does Codility have AI?

Yes. Codility includes an AI Assistant and supports coding agents such as Claude Code inside the Codility assessment environment. Employers switch AI on or off for each task in Screen and Skills Intelligence and for each interview in Interview, and every AI interaction is saved as reviewable AI activity. No AI is used in scoring.

What is a passing score on Codility?

There is no universal passing score. Each employer sets its own pass mark for each test, and some employers read the code instead of relying on the score alone. A score depends on hidden tests for correctness and performance, and candidates report that code that fails to compile scores zero.

Do employers read my code if I fail the hidden tests?

Some do. Each employer decides whether a person reviews the submitted code before making a decision. A hiring manager on Reddit describes being generous in letting candidates through to an interview, so a low score is not always the end of the process.

How much does Codility cost?

Codility’s Starter plan costs $1,200 a year for up to 120 invite credits, and Scale costs $6,000 a year for up to 300 invite credits. Both are self-serve. Larger teams get a Custom plan by quote. Prices were read on codility.com on 13 October 2026.