Senior / Founding Full-stack Developer

We - Lemon.io, a marketplace of vetted Senior Software Developers, are looking for a Senior Full-stack Developer for our client.

Location: due to regulatory requirements, candidates must be U.S. citizens (nuclear security), NYC on-site.

Rate & benefits: $140k–$200k per year; meaningful equity in a fast-growing company, standard benefits (health/dental/vision, FSA, wellness stipend) after a 6-month trial period.

Ideal candidate has experience in technical decision-making and in owning or leading processes in past projects. Nice-to-have: ex-founder, ex–big tech, or high-growth startups.

The Mission: The Company builds the intelligence layer that makes nuclear power actually deployable — collapsing regulatory workflows from months to days. You'll build alongside engineers from Tesla, SpaceX, Lockheed Martin, Google, and Microsoft. You'll learn from nuclear and national security experts who cut their teeth at the Nuclear Regulatory Commission, CIA, and NuScale.

Requirements:

• 4+ years of commercial experience in software engineering;
• Showcases evidence of 4+ years of full-stack development using Python and React;
• Experience with TypeScript — at least 3 years;
• At least 2 years of expertise with Next and Infrastructure provisioning (both of them).
• As the team scales, you'll mentor other engineers - founding Full-Stack Engineers typically grow into Head of Engineering, Product Lead, or CTO-track roles as the company scales.

The products you build will help:

• Onboard and train faster — reducing time-to-productivity from months to weeks
• Execute safety-critical workflows — with confidence, speed, and audit trails
• Keep vital infrastructure safe — because "good enough" isn't good enough in nuclear
• This is meaningful work in the truest sense — you're giving frontline professionals the tools they need to secure the energy backbone of our society.

Selection process

Pre-vetting with Lemon.io:

• Screening round
• Technical interview

Client's selection process:

• Screening round
• Technical round
• Final conversation with the Chief Nuclear Officer
• Final round with co-founder

NOT YOUR TECH STACK?

We have multiple projects available for Senior Developers. If you have 4+ years of commercial software development experience and are proficient in any of the following areas: React & Python, React & Node, React & Golang, AI Engineering, PHP & Angular, React & Java, Data Science, Blockchain (Web3/Solidity/Solana), Symfony & React, Symfony & Vue, Symfony & Angular, Symfony & JavaScript & Next.js & TypeScript, Data Analysis, React & PHP, Data Engineering, PHP & Vue, Vue & Node.js, DevOps, Android & iOS, Angular & Node.js, Python & Vue, MLOps, Rust, Golang, Shopify & JavaScript, Unreal Engine & C++, Python & LLM, Unity, Vue & Nuxt, Java & Spring, ML Engineering, or Python & Flask — we’d be happy to connect and match you with a suitable project.