Coding screens · async take-homes

Take-homes in a real IDE. Graded where nobody can touch the score.

Q: Can candidates see the hidden tests?

No. Hidden tests never reach the candidate's browser: a single-file challenge's test file stays out of their workspace, and hidden tests only run when the submission is graded on Kendor's servers. Test files candidates can see are restored from your starter before grading.

Q: What if the code needs the network?

Dependencies are installed before the network is cut. Anything that calls out while the tests run fails the same way for every candidate, so mock external services in the starter code.

Q: Does Kendor reject candidates automatically?

No. Test results and integrity signals are inputs for reviewers. A person advances or rejects every candidate.

Q: Do candidates need to install anything?

No. They open the link from their invitation in a browser and land in the IDE with the project's dependencies, terminal and preview ready. No webcam, no browser extension, no desktop app.

Candidates get VS Code, a terminal, a running preview of their app and language servers, all in the browser. Grading re-runs the work on Kendor's own servers at pinned versions with the network cut, so the score belongs to the code.

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rate-limiterTime left01:12:40← Back to AssessmentSubmit

Explorer

▾src

limiter.ts

server.ts

store.ts

▾test

limiter.test.ts

kendor.yaml

package.json

README.md

limiter.tslimiter.test.ts

1import type { Store } from './store';

3export class RateLimiter {

4 constructor(private store: Store, private limit = 100) {}

6 async allow(key: string): Promise<boolean> {

7 const bucket = Math.floor(Date.now() / 60_000);

8 const count = await this.store.incr(`${key}:${bucket}`);

9 return count <= this.limit;

10 }

11}

(method) Store.incr(key: string): Promise<number>

Terminal

$ npm test

✓ test/limiter.test.ts (6 tests) 412ms

Tests 6 passed (6)

:3000Preview

/api/check?key=ada

HTTP/1.1 200 OK

x-ratelimit-remaining: 97

{ "allowed": true }

mainTypeScriptNode.js 22Ln 8, Col 52

Three question types, one time limit.

Combine full projects, single-file exercises and written questions in one screen. The time limit covers the whole screen, and candidates move between questions freely.

Senior BackendLive

Challenges 3

rate-limitergithub.com/acme/rate-limiterNode.js 2210 testsReady

Open in editor

parse_durationSingle-filePython 3.128 testsReady

Open in editor

Sharing the limit across three regionsQ&AManual reviewReady

Edit brief & questions

Launch checklist

3 of 3 challenges ready

Time limit

90 minutes⌄

Proctoring

A clean re-run decides the score.

Results from the candidate's own terminal don't count. Grading rebuilds the workspace from your starter on Kendor's servers, lays only the files the candidate may edit on top, and runs your tests at the challenge's pinned versions. Hidden tests only run there.

The same versions for every candidate, so two submissions are graded alike.
No network while the tests run, so nothing outside the sandbox can change a result.
Tests, fixtures and install commands come from your starter, so editing them changes nothing.

← Back to submissionSubmission #1482 · read-only9/10 passed · recordedRun hidden tests

limiter.ts

6 async allow(key: string): Promise<boolean> {

7 const bucket = Math.floor(Date.now() / 60_000);

8 return (await this.store.incr(key)) <= this.limit;

9 }

Integrity signals, shown as evidence.

With proctoring on, tab switches, external pastes and fullscreen exits are logged with timestamps, and the Timeline tab plays the code back as it was written. Kendor doesn't turn them into a score. A reviewer reads them and decides what they mean.

ActivityProctored

3Tab switches2m 31s away in total

1External paste

0Fullscreen exits

9/10Tests passed

16:17:04Away from the screen for 1m 12s
16:31:40Pasted 214 characters from outsideconst windowStart = now - (now % this.windowMs);
16:52:18Away from the screen for 48s
17:03:55Away from the screen for 31s
17:24:09Submitted

Timeline

31:40 / 1:24:09Skipping idle1×2×4×

Attach a screen to a job posting.

Applicants get the screen the moment they apply, as a link on the confirmation page and an invitation email, so nobody sends invites by hand. Choose No screen and applications wait for manual review instead.

Senior Backend EngineerLive

Screening · optional

Attach a screen and applicants are routed into screening when they apply.

No screenReview applications manually.Senior Backend screenTypeScript · Python90 min

41All0Applied22Screening19In review

Every reviewer gives their own verdict.

Reviewers read the code, the test results and the activity, then each records a recommendation from Strong no to Strong yes, with a note the others can read. Then someone on the team advances or rejects the candidate.

Ada Okaforrate-limiter · 9/10 passed

RecommendationIn review · 2 of 3

MCMaya Chen · 2h agoWindow logic is right, and the tests read like documentation.Strong yes
JWJonas Wirth · 1h agoHandled the store failing without being asked.Lean yes
PNPriya Nair · nowReading the written answer.No verdict yet

Decision

Reject Advance

2 of 3 reviews in. You can still decide.

How it works

From repository to decision in three steps.

Build the screen
Import a repository or start from a single file, add tests (hidden ones too), and set the time limit.
Send it, or attach it to a role
Invite candidates directly, or let applicants receive it when they apply.
Grade, review, decide
Kendor grades a clean re-run, each reviewer records a recommendation, and you advance or reject.

Questions

Can candidates see the hidden tests?

No. Hidden tests never reach the candidate's browser: a single-file challenge's test file stays out of their workspace, and hidden tests only run when the submission is graded on Kendor's servers. Test files candidates can see are restored from your starter before grading.

What if the code needs the network?

Dependencies are installed before the network is cut. Anything that calls out while the tests run fails the same way for every candidate, so mock external services in the starter code.

Does Kendor reject candidates automatically?

No. Test results and integrity signals are inputs for reviewers. A person advances or rejects every candidate.

Do candidates need to install anything?

No. They open the link from their invitation in a browser and land in the IDE with the project's dependencies, terminal and preview ready. No webcam, no browser extension, no desktop app.

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