Hire JavaScript developers
These senior JavaScript developers default to TypeScript on modern projects and build full-stack web applications, APIs and browser-side products. In the first assessment, they read and fix code they didn't write with AI tools switched off.
01
TypeScript is now the working default
Most JavaScript engineers have moved to TypeScript as their day-to-day language, using plain JavaScript only where a project already commits to it. A developer who can't read and write TypeScript fluently is working at a disadvantage on almost every modern codebase.
02
AI writes JavaScript that looks right but breaks
Copilot and similar tools produce syntactically correct JavaScript that fails at runtime or introduces subtle bugs in async flows and closure scope. Developers now spend more time verifying and correcting AI output than they do writing boilerplate.
03
Build tooling makes debugging harder
Most stacks now run Vite, esbuild and layered transpilation, so a JavaScript developer needs to understand what the build chain actually produces as well as what the source says. Tracing a bug across a source map into minified output is a routine skill now.
How we assess JavaScript developers
Every engineer works through a fundamentals assessment with AI tools switched off and a second assessment with their own agents running. For JavaScript developers, these criteria carry the most weight.
- Debugging
In the first assessment, the developer works through a real JavaScript codebase with pre-seeded bugs, including async timing issues and closure mistakes, and has to locate and fix them without running to a search engine or AI assistant.
- AI output verification
In the second assessment, the developer uses their own AI tools to write JavaScript or TypeScript code and then has to catch and correct the errors the model introduced before shipping it.
- Context-switch hygiene
JavaScript work routinely spans frontend state, API calls, and build configuration inside a single assessment, so we watch whether the developer keeps track of what they changed and why as the scope shifts.
Hiring with Miyagami
- One senior engineer, full-time, at a fixed monthly fee
- Employment, payroll and compliance included, no recruitment fee
Timeline
- Three-month minimum
- Wrong fit: we replace at our cost
How to review AI-generated code
Reviewing AI-generated code changes some of what reviewers look for and keeps the rest. This entry covers both, plus the specific failure modes to check for.
How do you test software you didn't design
Standard coverage metrics mislead when you test software you didn't design. This entry explains what engineers should do instead when reviewing AI-generated code.
What is a coding agent
A coding agent is an AI system that writes, edits, runs and debugs code autonomously across multiple steps, without a human directing each action.
Questions about hiring JavaScript developers
How senior are the JavaScript developers you place?
The JavaScript developers we put forward have 6+ years' experience on average, and they've shipped and maintained production systems in JavaScript. Every one has passed both assessments, and you see both scorecards before you meet them.
How do you test JavaScript skill specifically?
Each developer completes two sixty-minute assessments in a real codebase. In the first assessment, with AI tools off, they read unfamiliar JavaScript, explain what it does and fix bugs. In the second assessment they work with their own AI agents, and you get the scorecards from both assessments.
How quickly can a JavaScript developer start?
You get a shortlist in five working days. From shortlist to first commit takes around three weeks, which covers interviews and onboarding. We only place full-time engineers, with a three-month minimum.
What does a JavaScript developer cost?
You pay a fixed monthly fee of €5,600 to €8,000 per full-time engineer, with employment, payroll and compliance included and no recruitment fee. The pricing page compares it with the all-in cost of a senior local hire in your country. Engagements are full-time with a three-month minimum, and if a placement doesn't work out, we replace them at our cost.
Do they work in our tools and codebase or their own setup?
They work in yours. Your developer joins your repository, your CI pipeline and your communication tools, and works with your team day to day.
Get a shortlist within five working days
You share the roles and the stack in a short form or a thirty-minute call. Within five working days you get named senior engineers to review, each with both scorecards.
ISO 27001Certified