Founding Full-Stack Engineer Job at YC Work at a Startup (San Francisco)

Founding Full-Stack Software Engineer – AI for Biopharma

Founding Full-Stack Engineer role at Equator, an AI-native startup building next...

Location

Spain , Barcelona

Salary:

70000.00 EUR / Year

Blu Selection

Expiration Date

Until further notice

Requirements

4–6 years of software engineering experience (mid to senior level)
Strong backend engineering skills with Python
Proficiency in React, Next.js, TypeScript, Node.js
Experience building data-heavy or versioned backend systems
Strong clean-code discipline and architectural thinking
English (Advanced/C1+)
Valid Spain work permit (no sponsorship available)

Job Responsibility

Architect scalable, auditable backend systems (Python, PostgreSQL, modern frameworks)
Build APIs enabling seamless collaboration between humans and AI agents
Develop clean, modular frontend interfaces using React, Next.js, and TypeScript
Implement and maintain data-heavy systems and structured knowledge frameworks
Write clean, precise code and contribute to strong engineering standards
Collaborate closely with founders, designers, and early users to deliver impactful features
Influence product, technical direction, and architectural decisions as a founding engineer

What we offer

Gym membership

Fulltime

Founding DevOps Engineer

As a Founding Engineer with a DevOps focus, you will play a central role in buil...

Location

France , Paris

Salary:

60000.00 - 80000.00 EUR / Year

Blu Selection

Expiration Date

Until further notice

Requirements

Strong full-stack engineering background with a DevOps mindset
Hands-on expertise in cloud platforms (GCP ideal): deployments, infra, CI/CD
Proficient in TypeScript and Python
Experienced with React, Next.js, and FastAPI
Solid knowledge of PostgreSQL and Redis
Ability to design scalable systems and deliver production-grade code quickly
Comfortable using AI-assisted coding tools (Cursor, Claude Code, Copilot)
Thrives in fast-moving, ambiguous, 0→1 environments
Fluent in English (French is a plus)

Job Responsibility

Build fast, lightweight, and reliable front-end applications (React)
Develop backend services powering conversational and AI-driven experiences
Design and maintain scalable cloud infrastructure (preferably GCP)
Set up CI/CD pipelines, observability, monitoring, and infra-as-code
Optimize performance, reliability, and security across systems
Own core architectural decisions and enforce best engineering practices
Ensure code quality, stability, and scalability from the ground up
Collaborate closely with early users and customers to iterate quickly

Fulltime

Founding iOS Engineer

Babylist is looking for a Senior iOS Engineer to join our newest venture—a stand...

Location

United States , Needham

Salary:

180100.00 - 225082.00 USD / Year

Babylist

Expiration Date

Until further notice

Requirements

Strong understanding of software development principles, capabilities, and limitations of the iOS platform
Well-versed in the intricacies of iOS development and can navigate its unique features and constraints
8+ years of proven experience in iOS app development using Swift
Comfortable working with Swift and SwiftUI and have a deep understanding of syntax, features, and best practices
Familiar with Foundation, SwiftUI, CoreAnimation and other foundational Apple frameworks and patterns
Hands-on experience with SwiftUI, Previews, and rapid prototyping
Passion for building consumer-facing products and moving quickly in the zero-to-one of a new product
Experience with AI-driven software development practices and tools
Solid understanding of the Android ecosystem, with direct Android development experience being a plus
Comfortable and enthusiastic about working in an AI-forward environment where AI tools are part of daily operations

Job Responsibility

Conceptualize, design and develop our new standalone iOS app, taking ownership of the entire development lifecycle
Develop features and functionality, ensuring a seamless and delightful user experience
Collaborate closely with your designer and product manager to translate requirements into technical specifications and user-friendly interfaces
Transform concepts and designs into intuitive and visually appealing iOS app interfaces
Collaborate closely with a full-stack web engineer to align on architecture, API design, and more
Write clean, efficient, and maintainable code following industry best practices and coding standards
Employ various testing techniques, write unit tests, and leverage debugging tools to identify and address any issues or bugs
Collaborate effectively with team members, actively participating in discussions and brainstorming sessions
Contribute to feature ideation, and providing insights to the team

What we offer

Competitive salary with equity and bonus opportunities
Company-paid medical, dental, and vision insurance
Retirement savings plan with company matching and flexible spending accounts
Generous paid parental leave and PTO
Remote work stipend to set up your office
Perks for physical, mental, and emotional health, parenting, childcare, and financial planning

Fulltime

Founding Full-Stack Engineer

As the Founding Full-Stack Engineer, you’ll be the first full-time engineer driv...

Location

United States

Salary:

200000.00 USD / Year

G2i Inc.

Expiration Date

Until further notice

Requirements

5+ years experience in full-stack engineering with production applications
Strong TypeScript experience with Node.js on the backend and React/Next.js on the frontend
Proven track record of building integrations with third-party systems and APIs
Comfortable leading zero-to-one development — from prototyping to production launch
Experience with AWS-first infrastructure (Lambda, API Gateway, S3, RDS, etc.)
Understanding of modern development workflows: CI/CD, automated testing, observability, and feature flagging

Job Responsibility

Lead the design and implementation of new full-stack applications that support insurance operations and product teams
Build, extend, and maintain integrations between internal systems and third-party services, carriers, and insurtech partners
Architect backend services, APIs, and business logic with a focus on performance, reliability, and scalability
Build frontend features with clean UI/UX that enhance internal productivity or partner/customer workflows
Translate business needs into high-quality technical solutions while anticipating future scale challenges
Participate in technical planning, code reviews, and documentation to establish engineering standards
Help define tech roadmap priorities based on business value and operational impact

Fulltime

Founding CTO

We’re an early-stage startup building a 0→1 product with strong founder convicti...

Location

United States , Miami

Salary:

125000.00 - 150000.00 USD / Year

G2i Inc.

Expiration Date

Until further notice

Requirements

Proven experience as a Founding Engineer, Lead Engineer, or CTO in an early-stage startup
Demonstrated success building and shipping a 0-to-1 product
Strong full-stack expertise, including backend systems, frontend frameworks, and data modeling
Experience designing systems with scalability and growth in mind
Comfortable working onsite in Miami, especially during the initial months
Willingness to balance execution today with leadership tomorrow

Job Responsibility

Lead the 0-to-1 build of the company’s core product
Architect and implement a cost-efficient, scalable tech stack
Own full-stack development, including backend services, frontend delivery, and data modeling
Make early architectural decisions with scalability and maintainability in mind
Act as a hands-on individual contributor in the early phase
Hire, mentor, and lead the engineering team as the company grows
Partner closely with founders on product vision, execution strategy, and technical trade-offs
Establish best practices for engineering, deployment, and security

What we offer

meaningful equity

Fulltime

Founding Product Engineer

Founding Product Engineer required to join a mission-driven Applied AI startup i...

Location

United Kingdom , London

Salary:

70000.00 - 160000.00 GBP / Year

Oho Group Ltd

Expiration Date

Until further notice

Requirements

Product-minded full-stack engineer who thinks beyond code and cares deeply about user outcomes
Comfortable operating at 0→1 and energised by ambiguity
Experienced in shipping production-ready products end-to-end
Strong in modern frontend frameworks (e.g. React / Next.js or similar)
Confident building scalable backend systems (e.g. Node, Python, or similar)
Highly autonomous, proactive, and excited by genuine ownership

What we offer

Competitive salary + meaningful equity
True ownership over product and technical direction
Direct collaboration with founders on product strategy and roadmap
Opportunity to work directly with users: gathering feedback, iterating rapidly, and seeing impact first-hand
High-trust, low-bureaucracy environment

Fulltime

Founding Full Stack Engineer

Oximy is building the control layer that makes AI safe and manageable for the wo...

Location

United States , San Francisco

Salary:

125000.00 - 250000.00 USD / Year

YC Work at a Startup

Expiration Date

Until further notice

Requirements

Strong full-stack experience
Comfort moving across frontend, backend, and systems code
Experience shipping production software used in real environments
Comfort working close to the OS (or curiosity to learn quickly)
Good judgment around tradeoffs
Clear communication
Bias toward ownership

Job Responsibility

Build core product surfaces
Work closely to the system boundary (network, user kernels etc)
Ship user-facing features, backend services, and native components across macOS and Windows
Work on performance, data correctness, and pipelines
Help shape the architecture that governs how AI usage is observed, interpreted, and acted on at scale
Work on core product surfaces across Pulse, Spend, and Oversight
Build high-signal UIs that explain AI usage to security, IT, finance, and AI teams
Build backend services and APIs that ingest and query large volumes of usage data
Build native macOS and Windows applications that operate close to the OS
Work on performance, reliability, and correctness across the stack

What we offer

Meaningful equity
Early-stage ownership

Fulltime

Founding AI Engineer

Flint is defining the next generation of websites: ones that can constantly buil...

Location

United States , San Francisco

Salary:

150000.00 - 250000.00 USD / Year

Flint

Expiration Date

Until further notice

Requirements

You are a product-first engineer
You have built and deployed AI products that real users depend on
You have extensive hands-on experience with prompt engineering, context optimization, and model fine-tuning
You have strong full-stack engineering skills with experience integrating AI into web applications
You regularly use AI IDEs like Cursor or Windsurf to code
You take ownership of problems from start to finish and are eager to learn whatever you need to succeed
You’re comfortable in a fast-paced environment with evolving requirements
You have enthusiasm for building MVPs and iterating based on user feedback

Job Responsibility

Designing and implementing production-grade agentic systems that power web experiences and marketing workflows, leveraging advanced prompt engineering and multi-agent architectures to do so
Architecting and optimizing RAG (Retrieval-Augmented Generation) systems with context engineering
Strengthening our engineering processes through robust evals, observability, and testing
Developing and maintaining the core application across frontend, backend, and infrastructure
Shaping our technical vision and leading architectural discussions. You'll make foundational decisions that influence both Flint's technical architecture and engineering culture.
Creating and testing prototypes to gather rapid feedback from users

What we offer

Historic office in Jackson Square (with 2 rooftops and a shower)
A crazy upside-down battlestation
20 PTO days a year and full health benefits
Lunch and a fully stocked snack bar at the office, incl. Cometeer coffee pods
Dog friendly
Competitive salary + equity

Fulltime

Founding Full-Stack Engineer

YC Work at a Startup

Location:
United States , San Francisco

Category:
IT - Software Development

Contract Type:
Not provided

Salary:

Job Description:

Job Responsibility:

Requirements:

Nice to have:

Additional Information:

Job Posted:
January 07, 2026

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