11x

Senior Fullstack Software Engineer, AI Agents

Posted 3 Days Ago

3 Locations

In-Office or Remote

150K-250K Annually

Senior level

Artificial Intelligence • Marketing Tech • Sales • Conversational AI

11x is building AI-native digital workers that automate entire GTM workflows—so teams can focus on what matters most.

The Role

Design, build, and iterate on fullstack systems for AI agents. Collaborate with teams to enhance UX and contribute to internal best practices while engaging in research related to AI technologies.

Summary Generated by Built In

Why 11x Now

At 11x, we're building autonomous digital workers that handle routine work end-to-end, freeing humans to focus on what they do best—creating, innovating, and building meaningful relationships. We're one of the world’s fastest-growing AI companies. We've achieved a 20x increase in ARR and raised $75M+ from leading investors including a16z and Benchmark. Our team works in-person in our San Francisco office.

About the Role

We're looking for a fullstack engineer with a passion for applied research and cross-functional collaboration. In this role, you’ll work closely with engineering leadership and our AI partners to prototype, build, and scale the next generation of autonomous digital workers.

This is an immersive opportunity to deepen your expertise in large language model applications, system design, and human-AI interaction—while learning how fast-moving AI companies operate from the inside. You’ll gain hands-on exposure to the latest model capabilities, contribute to internal experimentation, and help translate cutting-edge ideas into real-world tools.

What You'll Do

Design, build, and iterate on fullstack systems that power AI agents from concept to deployment.
Research and evaluate new approaches to agent orchestration, prompting strategies, and model alignment.
Collaborate with product, design, and engineering teams to improve UX and usability for non-technical users.
Share learnings, document findings, and contribute to the evolution of internal best practices.
Participate in peer reviews, brainstorming sessions, and technical deep dives with our global team.

Ideal Candidates Have

3+ years of experience in a product-oriented software engineering role.
A strong foundation in Typescript, React, NextJS, and NodeJS.
Experience working in fast-paced environments with a track record of rapid learning and iteration.
Interest in research, technical writing, or contributing to knowledge-sharing within a team.
Bonus: experience with large language models, prompt engineering, or AI infrastructure.

Canada base salary range: CAD $180,000 – $225,000

Seattle base salary range: USD $150,000 – $250,000

*Final offer will be based on a variety of factors, including role level, relevant experience, skills, and job-related expertise.

11x is an equal opportunity employer and does not discriminate on the basis of race, gender, sexual orientation, gender identity/expression, national origin, disability, age, genetic information, veteran status, marital status, pregnancy or related condition, or any other basis protected by law.

Top Skills

Nextjs

Node.js

React

Typescript

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The Company

HQ: San Francisco, CA

36 Employees

Year Founded: 2025

What We Do

At 11x, we’re not just building tools—we’re redefining how work gets done. We build autonomous digital workers that execute entire go-to-market workflows, end-to-end. Instead of just augmenting tasks with AI, 11x automates the full execution of sales, marketing, and RevOps processes so teams can focus on what they do best: building relationships, closing deals, and driving impact. Our technology integrates across GTM systems, adapts to real business logic, and learns continuously while delivering real outcomes. These aren’t just incremental improvements, they’re game-changing leaps forward in how companies grow.

Why Work With Us

Everyone here is a builder. You’ll be starting at the ground floor of a rocket ship company with the rare opportunity to leave your mark, shape the culture, and have a seat at the table as we scale. You’ll work side-by-side with a world-class team—people who move fast, think deeply, and care fiercely. The upside? Massive.