Senior Full-Stack Engineer (AI-Focused)

About the Role

We are looking for a Senior Full-Stack Engineer to help build the next generation of AI-powered features at Userflow and contribute to the company's transition toward an AI-first product.

You will own the development of AI features end to end, working across frontend interfaces, backend services, APIs, and LLM integrations. Your work will span Userflow's product builder, in-app SDK, Adoption Agent, and MCP connector.

This is a hands-on senior engineering role with significant autonomy and direct collaboration with the CTO, product, and design teams. You will help define the technical direction of AI-powered product development while delivering production-ready features that solve real customer problems.

We are looking for an engineer who combines strong full-stack development skills with practical experience building LLM-powered applications. You should be comfortable using AI coding agents as part of your daily workflow, making independent technical decisions, and taking ownership of the quality and business impact of what you ship.

Key Responsibilities

• Full-Stack Development: Build and maintain AI-powered product features across frontend interfaces, backend services, APIs, the product builder, and Userflow's in-app SDK.

• AI Product Development: Develop end-to-end experiences for Userflow's Adoption Agent and other AI-driven capabilities.

• Technical Strategy: Collaborate directly with the CTO and product team to define the technical roadmap and architecture for an AI-first product.

• LLM Engineering: Design and implement production-ready LLM workflows, including prompt engineering, retrieval-augmented generation (RAG), tool calling, agent orchestration, and evaluation systems.

• MCP and Agent Integrations: Extend Userflow's MCP connector and build integrations that allow customers to interact with Userflow through their own AI tools and workflows.

• Product Quality and Performance: Own the reliability, latency, and cost efficiency of AI features, establishing metrics to measure technical performance and customer value.

• AI-Assisted Engineering: Use AI coding agents such as Claude Code as part of everyday development, while establishing effective workflows, guardrails, and best practices.

• Cross-Functional Collaboration: Work closely with product, design, engineering, and leadership to translate customer problems into effective technical solutions.

Requirements

• 6+ years of professional experience building and maintaining production SaaS applications as a full-stack engineer.

• Strong proficiency in TypeScript and/or JavaScript across frontend and backend development.

• Experience with modern frontend frameworks and building responsive, user-facing product interfaces.

• Solid experience with Elixir and Python.

• Understanding of high-volume WebSocket traffic and its impact on application architecture and infrastructure.

• Hands-on experience building and shipping LLM-powered features in production, including model APIs, RAG, tool calling, or AI agents.

• Experience designing and evaluating LLM workflows, with an understanding of how to measure output quality and reliability.

• Daily experience using AI coding agents such as Claude Code or similar tools, with the ability to identify where human oversight and technical guardrails are necessary.

• Strong product mindset, with the ability to understand user problems, translate them into technical solutions, and measure the results.

• Ability to work independently, take ownership of technical decisions, and deliver features with minimal supervision.

• Clear communication skills and the ability to collaborate effectively with engineers, product stakeholders, and executive leadership.

• English proficiency: C1 or C2, with the ability to communicate technical concepts and participate actively in a distributed international team.

Preferred Qualifications

• Experience building Model Context Protocol (MCP) servers, connectors, or other agent-oriented tooling.

• Experience developing embedded JavaScript SDKs or in-app product experiences.

• Familiarity with LLM observability, tracing, monitoring, and evaluation tools.

• Previous experience with product-led growth (PLG), user onboarding, or product adoption platforms.

• Experience designing scalable AI architectures and managing model performance and inference costs.

• Experience working in small, product-focused engineering teams.

Compensation & Logistics

• Work Arrangement: Fully remote.

• Hiring Region: Latin America.

• Time Zone: Must be able to maintain strong working-hour overlap with US-based leadership and product engineering teams.

• Seniority: Senior individual contributor.

• Reporting Structure: Directly reports to the CTO.

• Compensation: USD-based, to be determined based on experience and technical expertise.

What Success Looks Like

First 90 Days

• Ship at least one AI-powered feature to production and make it available to customers.

• Establish a functional AI-assisted development workflow involving product, design, and engineering.

• Become familiar with Userflow's architecture, product ecosystem, and existing AI capabilities.

• Identify opportunities to improve the quality, performance, and delivery speed of AI-powered features.

First 12 Months

• Deliver AI features that demonstrate measurable improvements in product adoption and customer retention.

• Establish reusable engineering patterns for building, evaluating, and deploying AI-powered capabilities.

• Contribute meaningfully to the company's transition toward an AI-first product architecture.

• Help establish AI-assisted development practices adopted across the engineering team.

• Maintain high standards for product quality, performance, reliability, and cost efficiency.

Company Overview

Userflow is a product adoption platform that helps businesses guide their users toward realizing the full value of their products.

The platform enables companies to create in-app experiences that improve user onboarding, engagement, and product adoption. AI is increasingly central to its product strategy, with capabilities such as the Adoption Agent and MCP connector helping customers interact with and get more value from their products.

Userflow reaches more than 12 million end users through customer applications across the US and EU.

Joining Userflow means contributing directly to the evolution of an established SaaS product, helping shape its AI strategy, and building features that reach millions of users.

Why Join?

• Shape an AI-first product: Help define how AI transforms the product, working directly with the CTO.

• End-to-end ownership: Build features across the full stack, from user interfaces to backend systems and AI integrations.

• AI-driven engineering culture: Work with a team that actively uses AI coding agents in its daily development process.

• Direct impact: Ship features used by more than 12 million end users.

• Autonomy and influence: Join a small engineering team where your technical decisions and contributions have a direct impact on the product.