Senior Fullstack Developer

Newcode; Chicago (IL); On-site; USD 120,000 - 180,000; Full time

Job summary

Newcode.ai in Chicago is seeking a senior fullstack engineer to own features end-to-end—from backend FastAPI services to a responsive React UI. The role emphasizes building robust APIs, streaming updates, and interfaces capable of handling large document workloads.

You’ll push for high-quality code, thoughtful architecture, and practical AI tooling usage, with a startup mindset that adapts quickly and ships value rapidly.

Qualifications

• At least five years building and shipping fullstack work, depth matters more than quantity.
• Able to design clean APIs and build a good UI on top of them.
• You care how it turns out: readable code, a UI that feels right, an architecture you’d defend.
• You use AI coding tools (Claude Code, Cursor, Copilot) effectively and don’t rely on AI to write code you don’t understand.
• Keen to dive deeper into LLMs, RAG, and agents.
• Comfortable in a startup that shifts quickly.

Responsibilities

• Building AI features end to end, API through UI.
• Making models usable: streaming responses, real-time updates, and interfaces that handle many documents without feeling slow.
• Owning quality and architecture on both sides of a feature.
• Collaborating with frontend or backend specialists when deeper work is needed, and handling the rest yourself.

Skills

React

TypeScript

FastAPI

Python

API design

Tools

Next.js

React Query

Zustand

shadcn/ui

LangChain

LlamaIndex

WebSocket

SSE

Job description

Who are we?

At Newcode.ai, we’re on a mission to reshape how organizations put AI to work in their day-to-day operations. In few months, we’ve moved from vision to reality—building products our clients truly love. As part of our fast-growing and highly ambitious team, you won't just drive the future of AI—you’ll help define it.

The role

You’ll build features the whole waythrough:theFastAPIservice and data work on the back, the React interface on the front. Most of what we build puts a language model in front of someone doing real work, so a typical feature might mean wiring up retrieval and an LLM call on the backend, then building the streaming, document-heavy UI that makes it usable.

We want someone who can carry a feature from idea to production without handing it over a wall. You should be at home in aCelery task and in aReact component, and able to handle routine work on either side without waiting for a specialist to unblock you.

What You'll Do

• Building AI features end to end, API through UI.

• Making models usable: streaming responses, real-time updates, and interfaces that handle a lot of documents without feeling slow.

• Owning quality and architecture on both sides of a feature.

• Pulling in our frontend or backend specialists when something needs realdepth, andhandling the rest yourself.

Who You Are

• At least five years building and shippingfullstackwork. Depth matters more to us than the number.

• Comfortable on both sides for real: you can design a clean API and build a good UI on top of it.

• You care how it turns out: readable code, a UI that feels right, an architectureyou'ddefend.

• You use AI coding tools (Claude Code, Cursor, Copilot) and use them well. They make you faster; theydon'twrite code youdon'tunderstand, and youwouldn'tpass sloppy AI output in review.

• Keen to go deeper on LLMs, RAG, and agents.

• Fine working in a startup that shifts under you.

Experience we expect with the stack

• React: 5+ years

• TypeScript: 3+ years

• FastAPI/ Python: 3+ years

• PostgreSQL

• Redis: 2+ years

• Tailwind CSS: 1+ year

Nice to have: Next.js, React Query,Zustand,shadcn/ui;LangChainorLlamaIndex; streaming over SSE or WebSocket.

Visa Sponsorship: At this time, Newcode is unable to provide visa sponsorship. Candidates must be authorized to work in the applicable country without employer sponsorship.

Why Newcode.ai?

• Join a collaborative, high-energy team where your ideas are heard and your impact is real.

• Help design, build, and launch products shaping the future of artificial intelligence.

• Work flexibly, in English, from anywhere in the EU.