Can we test async runtimes specifically?

Yes. Tokio, async-std and smol can each be pre-loaded with a representative workload.

Can we test WASM or embedded Rust?

Yes. wasm-pack and a no_std setup with a QEMU target are available.

Do candidates need to install anything?

No. The workspace runs in their browser. Terminal, editor, ports and dashboards are all served from the EasyEnv workspace, so candidate setup is zero.

How do you score a hands-on challenge?

Each challenge has automated checks (did the service come back, did the test pass, did the right log message appear) plus a recording your team can replay. Most reviews take under five minutes.

Can we keep AI disabled for this role?

Yes. AI access is a per-interview setting. Block it for fundamentals, then allow it later in the loop to assess AI collaboration separately.

Interviews/Application Development/Rust Developer

Hire Rust Developers
who actually ship code the borrow checker approves

With EasyEnv we build a fit test for the role. Use it to cut the noise at the top of the funnel, or to go deep on the candidates who matter.

You can even evaluate how this person works with AI. So you hire the engineer who can ship, not the one who looks good in a slide.

RustTokio · asyncCargo · Clippyunsafe · perfLive or take-home

Request a Demo Create a Free Account

Real Linux VM

Not a sandbox

systemd, kernel, full toolchain

Browser-based

Zero install for candidates

One link and they are in

Auto-graded

Pass / fail checks per challenge

Plus the full session replay

A great Rust developer treats the borrow checker as a teacher. The good ones reach for owned types when the lifetime gets weird, justify every unsafe, and prove perf wins with criterion. EasyEnv hands the candidate a real cargo workspace with a real lifetime error and a benchmark that does not lie.

Inside a live interview

What you see when they work.

Real cargo workspace, real criterion, every keystroke recorded.

billing-api

AMS

Billing-api

src

billing.py

auth.py

models.py

tests

test_billing.pyM

test_auth.py

pyproject.toml

README.md

Pybilling.py

1

2

3

4

5

6

7

8

9

10

11

12

13

from decimal import Decimal

def calculate_total(items: list[dict]) -> Decimal:

# Sum line totals using Decimal for currency precision

total = Decimal("0")

for item in items:

total += Decimal(str(item["price"])) * item["qty"]

return total

candidate@rust-workspace:~

alice@dev:~/billing-api$

● mainPython 3.12

Claude · ready

Claude

You

Refactor calculate_total to use Decimal for currency math, and add a test.

Claude

Ask Claude...

Mike

Sam

How it works

Three steps. Zero infra to maintain.

01

Pick the fit test

Use a ready-made challenge or ask us to build one for your stack. Live, take-home, or both.

02

Send one link

The candidate clicks. A full Linux workspace boots in their browser. No installs, no VPN, no zoom-share.

03

Review at 2x

Replay the session, read the auto-graded checks, and decide. Most reviews take under five minutes.

The problem

Why hiring a Rust Developer is hard.

1

Rust depth ranges from "compiled hello world" to "wrote an allocator". The interview has to find the level.

2

Async Rust is its own learning curve. CVs cannot show that.

3

unsafe is where trust is earned. You need to see the reasoning.

4

Perf claims are easy to make and hard to defend.

The fit test

What we measure for a Rust Developer.

Every area runs inside a real production-like workspace. The candidate works in a browser, the session records itself.

01

Lifetimes and ownership

A function the borrow checker rejects. They explain before they patch.

02

Async with Tokio

A spawn that holds a !Send guard. They restructure rather than slap Arc<Mutex>.

03

Performance with criterion

A hot loop that should be 3x. They benchmark, optimise, prove.

04

Justified unsafe

A small unsafe block that needs a comment. They write the invariant.

05

Cargo and ecosystem

A workspace with feature flag drift. They reconcile without breaking downstream.

06

AI collaboration

Allow AI for boilerplate and grade whether they ran cargo test plus clippy after.

The stack we put in front of them.

Real tools, pre-installed, accessible from the workspace terminal.

RustCargoTokioasync-stdClippycriterionrayonserdeaxumactixsqlxdieseltonicwasm-bindgenmiriflamegraph

Sample challenges

What a Rust Developer interview looks like.

Pick from our library or ask us to build a challenge for your stack. Each one is a real workspace, not a snippet.

Challenge 01

The function that will not compile

Scenario

A function returning a reference that outlives its source. The compiler is loud.

What you learn

Whether they restructure the data flow or just clone.

In the workspace

$ ls challenges/

workspace, runbook.md, README.md

candidate has:

· a real Linux box in the browser
· kubectl, docker, terraform, jq, yq
· cluster, repo and cloud creds pre-wired
· auto-checks running in the background

interviewer sees:

· every keystroke + every command
· terminal + screen recording
· auto-graded pass/fail per check

AI in the loop

Score the engineer, and how they work with AI.

AI writes Rust that compiles and allocates everywhere. EasyEnv records prompts so you see whether the candidate ran clippy and the benchmark after the LLM-suggested refactor.

Allow or block AI per question, not per interview

Full prompt and response history replayed in the review

Score "verifies AI output" as a separate signal

Ready to hire a Rust Developer who ships?

Set up your first interview in under an hour. We will help you build a fit test for this role on your stack.

Request a Demo Create a Free Account

Hire Rust Developerswho actually ship code the borrow checker approves

What you see when they work.

Three steps. Zero infra to maintain.

Pick the fit test

Send one link

Review at 2x

Why hiring a Rust Developer is hard.

What we measure for a Rust Developer.

Lifetimes and ownership

Async with Tokio

Performance with criterion

Justified unsafe

Cargo and ecosystem

AI collaboration

The stack we put in front of them.

What a Rust Developer interview looks like.

The function that will not compile

Score the engineer, and how they work with AI.

Anyone uses AI.Few use it well.

AI Understanding

Prompt Quality

Critical Review

Responsible Usage

Where EasyEnv shines.

Ready to hire a Rust Developer who ships?

Hiring a Rust Developer, answered.

Hire Rust Developerswho actually ship code the borrow checker approves

What you see when they work.

Three steps. Zero infra to maintain.

Pick the fit test

Send one link

Review at 2x

Why hiring a Rust Developer is hard.

What we measure for a Rust Developer.

Lifetimes and ownership

Async with Tokio

Performance with criterion

Justified unsafe

Cargo and ecosystem

AI collaboration

The stack we put in front of them.

What a Rust Developer interview looks like.

The function that will not compile

Score the engineer, and how they work with AI.

Anyone uses AI.Few use it well.

AI Understanding

Prompt Quality

Critical Review

Responsible Usage

Where EasyEnv shines.

Ready to hire a Rust Developer who ships?

Hiring a Rust Developer, answered.

Hire Rust Developers
who actually ship code the borrow checker approves

Anyone uses AI.
Few use it well.

Hire Rust Developers
who actually ship code the borrow checker approves

Anyone uses AI.
Few use it well.