Senior Fullstack Engineer

Jobtailor; Boston (MA); On-site; USD 140,000 - 190,000; Full time

Job summary

Jobtailor in Boston, MA is seeking an experienced software engineer to build and ship growth features across the full stack, directly impacting revenue, conversion, and retention. You will design architectures for growth features, experiments, and lifecycle monetisation flows, while using AI coding tools as a core part of engineering workflows.

You will mentor junior engineers, participate in architecture discussions, run end-to-end A/B tests, and stay current with AI tooling and developer

Qualifications

• 5+ years of full-stack engineering experience shipping production features in TypeScript/Node.js and React

Responsibilities

• Build and ship features across the full stack that grow revenue, conversion, and retention

Skills

Full-stack engineering

TypeScript

Node.js

React

AI coding tools

A/B testing

Feature flags

Data-driven engineering

Communication

Bias for action

Tools

Cursor

Claude

Copilot

Job description

• Build and ship features across the full stack that directly grow revenue, conversion, and retention - you'll see your work in the metrics within days of shipping.
• Design and implement the technical architecture for growth features, in‑app experiments, and lifecycle and monetisation flows – making pragmatic decisions that balance speed with maintainability.
• Identify and build growth loops – referral mechanics, pricing and packaging experiments, and features that compound usage across both sides of the marketplace.
• Use AI coding tools (Cursor, Claude, Copilot, or whatever works best for you) as a first‑class part of your engineering workflow – we actively encourage this and want to learn from how you do it.
• Contribute to how the team uses AI beyond your own workflow – sharing patterns, tools, and approaches that make the whole squad faster and better.
• Work closely with the PM and designer in tight, fast feedback loops – you're not waiting for specs to be 'done' before you start thinking about implementation.
• Run A/B experiments end‑to‑end: implement the test, instrument the events, analyse the results, and feed the findings back into the next iteration.
• Write clean, well‑tested code that the team can build on – and raise concerns when you see technical debt accumulating that will slow us down later.
• Participate in architecture and technical design conversations – your opinion on how to build things matters here, not just that you can build them.
• Stay close to the latest in AI tooling, engineering practices, and developer productivity – and bring what you learn back to the team.
• Mentor more junior engineers and help build an engineering culture that's proud of both its speed and its craft.

Requirements

• 5+ years of full‑stack engineering experience, with a track record of shipping production features in TypeScript/Node.js and React (or equivalent modern stack).
• A genuine bias for action – you default to building and learning, not deliberating and waiting. You know how to ship something imperfect and iterate fast.
• Active, fluent use of AI coding tools in your day‑to‑day workflow – you've moved beyond the basics and have a clear view on where AI makes you faster and where it doesn't.
• Strong instincts for technical trade‑offs in a fast‑moving environment – you can tell the difference between debt that's fine to carry for now and debt that will hurt the team in two sprints.
• Experience building and instrumenting A/B experiments, feature flags, or other data‑driven engineering patterns.
• Comfort working close to the product – reading dashboards, questioning metrics, and understanding the 'why' behind what you're building.
• Clear, direct communication – you can explain a technical decision to a PM in two sentences and to a fellow engineer in a whiteboard session.
• Based in or willing to commute to Boston regularly for in‑person collaboration.

Core Competencies

Demonstrates extensive experience in Full‑Stack Engineering with a focus on TypeScript, Node.js, and React, while effectively utilizing AI coding tools to enhance productivity. Capable of designing and implementing growth features and A/B experiments, with strong communication skills to collaborate closely with product managers and designers.

Tools & Technologies

• AI Coding Tools
• Cursor
• Claude
• Copilot