Now in early access

Your candidates use AI to pass coding tests. What if that was the point?

Drop candidates into a real coding environment with AI tools. See who actually ships.

How It Works

VS Code — solution.py

solution.py

models.py

routes.py

VS Code — models.py

solution.py

models.py

routes.py

Terminal

~/workspace/challenge $

python manage.py migrate

Operations to perform: Apply all migrations

Applying users.0012_soft_delete... OK

Terminal — Server

~/workspace/challenge $

python manage.py runserver

Watching for file changes with StatReloader

Performing system checks...

System check identified no issues (0 silenced).

Starting development server at http://127.0.0.1:8000/

Quit the server with CONTROL-C.

[12/Feb/2026 10:32:15] "GET /api/users/ HTTP/1.1" 200 1842

[12/Feb/2026 10:32:16] "POST /api/users/delete/ HTTP/1.1" 200 42

Claude Code

Claude Code Sonnet 4.5

Slack

Acme Inc

Channels

# eng

# general

# design

# devops

# standup

DMs

Sarah C.

Alex R.

Jordan K.

# eng-team

Mike T. 9:45 AM

Pushed auth refactor to staging. Can someone review?

👍 3

Alex Rivera 10:15 AM

Reviewed — LGTM. Deployed v2.3 to staging.

Today

Sarah Chen 10:23 AM

Hey! Can you work on the delete account feature? Most requested item — users want to fully remove their accounts.

Jordan Kim 10:24 AM

+1, been in the backlog forever

🙌 2

Sarah Chen 10:32 AM

VibeArena — Session Insights

AI Prompts

Slack Msgs

47m

Duration

A+

Approach

Time Allocation

40%

25%

20%

15%

Score Breakdown

Session Timeline

VibeArena — Test Results

4/6

✓ 4 passed ✗ 2 failed • 1.23s

✓

test_soft_delete_user

✓

test_anonymise_display_name

✗

test_posts_preserved

✓

test_delete_api_endpoint

✗

test_cascade_cleanup

✓

test_error_handling

Coverage

78%

Score Distribution

Execution Time

Complexity

Test Timing

VibeArena — Session Replay

Watch full session — 47:12

StartSlackAI ChatCodingTests

47m

Duration

AI Prompts

Slack Msgs

Score

The shift

LeetCode was built for a different era. The industry knows it.

Meta, Shopify, Canva, Cisco, companies are dropping algorithm interviews. The question isn't if algorithms are over, it's what comes next.

How it works

A job simulation, not an exam.

Real environment

A full workspace in the browser. Virtual colleagues in Slack, a code editor, complex codebases, packages and AI tools.

Solve with AI

Challenges test how candidates reason about code and architectural choices. "Claude pls fix. Don't make mistakes" won't work.

Follow the process

Session replay and summaries show you thought process and decision making skills. You see what they built, how they got there, and whether it works.

What you see

The full picture. Not just the output.

Every AI prompt they wrote and what they did with the response
Where they followed the AI vs. where they pushed back
How they extracted the real requirements from a vague PM brief
Automated test results — pass or fail, no ambiguity

Signal, not surveillance.

No lockdown browser. No webcam. No keystroke monitoring. Your candidates are professionals — treat them like it.

Challenge library

Real problems. Not algorithms.

Each challenge drops you into a full virtual environment — databases, servers, APIs — the same stack you'd debug at work.

Debug a permissions system where the AI confidently gives the wrong answer

Hard

Node.js + PostgreSQL + RBAC middleware35 min

Fix a database migration that silently corrupts user records

Medium

Python + SQLAlchemy + PostgreSQL25 min

Trace a payments bug across three microservices

Hard

Express + Stripe API + Redis + Docker40 min

From the blog

Coding Challenges AI Can't Solve (and How to Design Them) →

If an AI can write any arbitrarily complex algorithm, what is it that the engineer actually does? We think the work breaks down into three distinct skills.

The skill nobody tests for →

Over the last year, the best engineers have completely changed how they work. They don't write code by hand anymore, they talk to agents, interrogate them, make architectural decisions, scope projects, and verify output.