Full-Stack Engineer

Build like a founder. Ship like Spartan. Our customers are scaling fast — and so are we. That’s why we’re looking for a Fullstack Engineer (React/TypeScript) to join our world-class team.

At Spartan, we don’t act like vendors. We embed with startups backed by YC, Pear VC, a16z, Techstars , and more — partnering with founders and engineers from Stanford, MIT, Yale, Google, Amazon, Uber, and beyond. Together, we help launch MVPs in 30 days and scale systems that power millions of users.

This isn’t “just another engineering role.” It’s a chance to build across the stack, craft intuitive user experiences, and design scalable backend systems — seeing your work directly power companies raising millions on the global stage.

You’ll also be working at the frontier of AI: 70% of our portfolio today is LLM-powered. Our engineers leverage the latest tools like Cursor, Claude, and Codex to accelerate development and integrate AI-native workflows into everything we build.

What You’ll Do

• Build scalable, reliable, and beautiful fullstack applications with React, TypeScript, and Node.js/Next.js.
• Work directly with US startup founders and product leaders — shaping solutions that drive their business forward.
• Ship fast with a proven process: async standups, PRDs/RFCs, code reviews, automation.
• Work in an AI-native workflow — leveraging tools like Cursor, Claude, and Codex to reduce boilerplate and boost iteration speed.
• Uphold engineering excellence — clean code, testing, documentation, reliability.
• Help shape Spartan’s engineering culture — we’re 1% pass-rate engineers who work like founders, not contractors.

What We’re Looking For

• Fluent in English — you’ll work directly with US startup founders.
• 3+ years building production-grade applications.
• Strong expertise in React, TypeScript, and modern JavaScript (ES6+).
• Solid backend experience (Node.js, Next.js, APIs, databases).
• Knowledge of frontend fundamentals: state management, performance optimization, accessibility.
• Experience with design systems, responsive UI, and API integrations.
• A builder’s mindset — you care about solving problems, not just writing code.

Tech We Use Every project brings a different stack, so in a year here you’ll touch more of this list than most engineers do in five. What we adopt is decided by our engineers through an internal Tech Radar, not handed down from a slide deck.

• Languages: Go
• Java/Kotlin/Scala
• TypeScript
• Python
• Data: Postgres
• MongoDB
• DynamoDB
• ElasticSearch
• Redis
• LLM stack: Claude API
• OpenAI API
• MCP
• LangGraph
• LangSmith
• Vector search: pgvector
• Pinecone
• Qdrant
• Weaviate
• Streaming: Kafka
• Pulsar
• SQS
• AWS Kinesis
• GCP Cloud Tasks
• Data processing: Spark
• Flink
• Cloud: AWS
• GCP
• Azure
• Kubernetes
• CI/CD: Jenkins
• GitHub Actions
• Observability: DataDog
• Prometheus
• Grafana
• ELK Stack
• AI tooling: Cursor
• Claude
• Codex

Career Growth

• Work directly with founders from YC, Stanford, MIT, Yale, Google, Amazon, Uber, and more.
• Exposure to LLMs, AI agents, cloud infra, and real-time systems.
• Transparent career path and mentorship from engineers who’ve taken 3 companies to IPO.
• Every project feels like its own mini-startup.

Why Spartan

• 50+ MVPs launched, 3 IPOs, $100M+ raised by the startups we build with.
• 95% engineer retention. People stay because the work is worth staying for.
• You build zero to one. Blank repo to live product in weeks. Most engineers get that chance once in a career. Here it’s the job.
• Your work is visible. What you ship this month is in a founder’s investor demo next month.
• No layers, no bureaucracy. You talk to the decision-maker directly, and decisions land in hours, not weeks.
• Every project is a new market, a new stack, a new problem. One year here teaches what three years elsewhere would.
• You’ll never just take tickets. You’ll own problems, ship fast, and grow with the founders we partner with.

Benefits & Perks

• 💰 Competitive salary, 100% salary during probation
• 🏝 Unlimited PTO + public holidays
• 🩺 Premium healthcare insurance + annual health check
• ⚽ Sports clubs for every taste: football, badminton, billiards, pickleball
• 🎮 PS5 and Nintendo at the office
• 🏃 Strava yearly subscription
• 🏠 Hybrid working style, flexible hours
• ✈️ Annual company trip + monthly team parties
• 💻 MacBook provided
• 📜 Social insurance per Labor Law

**Work Loc…