Interviews/Application Development/TypeScript Developer

Hire TypeScript Developers
who actually use the type system, do not fight it

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.

TypeScriptType system depthGenerics · narrowingtsc · ESLintLive 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 TypeScript developer treats the compiler as a design tool, not a gauntlet. The good ones reach for unknown over any, narrow with discriminated unions, and refactor with confidence because their types pay rent. EasyEnv hands the candidate a real project with a real type bug and a refactor that has to land green.

Inside a live interview

What you see when they work.

Real TS project, real refactor, 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

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@ts-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.

Pick the fit test

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

Send one link

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

Review at 2x

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

The problem

Why hiring a TypeScript Developer is hard.

TypeScript depth ranges from "annotated JS" to "type-level chess".

any erodes type safety silently. The interview has to surface the habit.

Generics taste is real. Few candidates can talk about variance with examples.

Refactors that break inference are easy to write and painful to ship.

The fit test

What we measure for a TypeScript Developer.

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

Narrowing and unions

A discriminated union with a forgotten case. The compiler is silent because of any.

Generic API design

A helper that loses inference at the call site. They tighten without breaking callers.

Strictness and config

A tsconfig with islands of any. They turn the dial up safely.

Refactor at scale

A field rename across 80 files. They use the language server, not sed.

Build perf

A 60s tsc that should be 10s. They isolate modules and project refs.

AI collaboration

Allow AI for refactors and grade whether they kept tsc --strict green.

The stack we put in front of them.

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

TypeScripttscts-nodetsxESLintPrettierProject ReferencesZodio-tsEffectfp-tsesbuildswcVitestJestTS Language Server

Sample challenges

What a TypeScript 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 silent case

Scenario

A discriminated union with three variants and a fourth slipping through via any.

What you learn

Whether they replace any with unknown and exhaustiveness checks.

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 is happy to silence the compiler with as any. EasyEnv records prompts so you see whether the candidate kept tsc --strict green 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 TypeScript 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

Role FAQ

Hiring a TypeScript Developer, answered.

Yes. Type-level puzzles (conditional types, mapped types, infer) can be set as standalone questions.

Yes. The workspace can be pre-loaded with a 50k-LOC project and a target refactor.

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

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.

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/TypeScript Developer

Hire TypeScript Developers
who actually use the type system, do not fight it

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.

TypeScriptType system depthGenerics · narrowingtsc · ESLintLive 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

Inside a live interview

What you see when they work.

Real TS project, real refactor, 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

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@ts-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.

Pick the fit test

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

Send one link

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

Review at 2x

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

The problem

Why hiring a TypeScript Developer is hard.

TypeScript depth ranges from "annotated JS" to "type-level chess".

any erodes type safety silently. The interview has to surface the habit.

Generics taste is real. Few candidates can talk about variance with examples.

Refactors that break inference are easy to write and painful to ship.

The fit test

What we measure for a TypeScript Developer.

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

Narrowing and unions

A discriminated union with a forgotten case. The compiler is silent because of any.

Generic API design

A helper that loses inference at the call site. They tighten without breaking callers.

Strictness and config

A tsconfig with islands of any. They turn the dial up safely.

Refactor at scale

A field rename across 80 files. They use the language server, not sed.

Build perf

A 60s tsc that should be 10s. They isolate modules and project refs.

AI collaboration

Allow AI for refactors and grade whether they kept tsc --strict green.

The stack we put in front of them.

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

TypeScripttscts-nodetsxESLintPrettierProject ReferencesZodio-tsEffectfp-tsesbuildswcVitestJestTS Language Server

Sample challenges

What a TypeScript 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 silent case

Scenario

A discriminated union with three variants and a fourth slipping through via any.

What you learn

Whether they replace any with unknown and exhaustiveness checks.

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 is happy to silence the compiler with as any. EasyEnv records prompts so you see whether the candidate kept tsc --strict green 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 TypeScript 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

Role FAQ

Hiring a TypeScript Developer, answered.

Yes. Type-level puzzles (conditional types, mapped types, infer) can be set as standalone questions.

Yes. The workspace can be pre-loaded with a 50k-LOC project and a target refactor.

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

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.

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

How to Hire a TypeScript Developer | Type-System Interviews | EasyEnv | EasyEnv

Hire TypeScript Developerswho actually use the type system, do not fight it

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 TypeScript Developer is hard.

What we measure for a TypeScript Developer.

Narrowing and unions

Generic API design

Strictness and config

Refactor at scale

Build perf

AI collaboration

The stack we put in front of them.

What a TypeScript Developer interview looks like.

The silent case

Score the engineer, and how they work with AI.

Ready to hire a TypeScript Developer who ships?

Hiring a TypeScript Developer, answered.

Hire TypeScript Developerswho actually use the type system, do not fight it

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 TypeScript Developer is hard.

What we measure for a TypeScript Developer.

Narrowing and unions

Generic API design

Strictness and config

Refactor at scale

Build perf

AI collaboration

The stack we put in front of them.

What a TypeScript Developer interview looks like.

The silent case

Score the engineer, and how they work with AI.

Ready to hire a TypeScript Developer who ships?

Hiring a TypeScript Developer, answered.

Hire TypeScript Developers
who actually use the type system, do not fight it

Hire TypeScript Developers
who actually use the type system, do not fight it