Pasito (YC S22) - Fullstack engineer UI

📍 Job Overview

Job Title: Fullstack Engineer (UI-Focused)

Company: Silver.dev (Pasito)

Location: Buenos Aires, Argentina (Remote OK within Argentina & Uruguay)

Job Type: FULL_TIME

Category: Software Engineering / Product Development

Date Posted: September 01, 2026

Experience Level: Mid-Level (2-5 years)

Remote Status: Fully Remote

🚀 Role Summary

• Spearhead the development of sophisticated, state-rich user interfaces for Pasito's AI-native benefits workspace, focusing on user experience and interaction quality.

• Integrate cutting-edge AI and LLM-powered workflows directly into the core product, particularly within complex text editing, data-dense, and collaborative environments.

• Collaborate closely with Product and Design teams to translate intricate customer workflows and business requirements into robust, scalable, and intuitive software solutions.

• Drive architectural decisions for UI systems, setting high standards for correctness, performance, and maintainability as an early member of the engineering team.

• Operate across the full stack, with a primary emphasis on delivering end-to-end UI experiences that define how AI-native software functions in a regulated industry.

📝 Enhancement Note: While the title is "Fullstack Engineer," the description heavily emphasizes a "UI-first, product-driven" approach with a focus on building complex UIs. This suggests a role where frontend expertise is paramount, but the ability to contribute to the backend as needed for end-to-end feature delivery is crucial. The company's focus on AI and legacy industry transformation implies a need for engineers who can bridge innovation with precision and trust.

📈 Primary Responsibilities

• Design, develop, and own complex, state-rich UI systems, leveraging technologies like ProseMirror/Tiptap and Yjs to create seamless editing, collaboration, and data management experiences.

• Implement and refine AI-native product features, such as AI agents for data extraction and structuring, directly within the user interface to enhance functionality and user workflows.

• Actively participate in cross-functional collaborations with Product Management, Design, Sales, and Client Success teams to deeply understand client needs and translate them into actionable product requirements and technical specifications.

• Continuously iterate on existing UI patterns, challenge established assumptions, and contribute to defining and evolving the product's user experience and technical architecture as the company scales.

• Ensure the quality, performance, and trustworthiness of user-facing systems through robust frontend testing, code reviews, and adherence to best practices in a high-impact, regulated industry.

📝 Enhancement Note: The responsibilities highlight a strong emphasis on ownership and end-to-end feature development, particularly concerning complex UI components and AI integration. The role requires proactive problem-solving and a commitment to quality in a domain where precision is critical (employee benefits).

🎓 Skills & Qualifications

Education: While no specific degree is mandated, a strong academic foundation in Computer Science, Software Engineering, or a related field is beneficial. Practical experience and demonstrated proficiency will be prioritized over formal education.

Experience: 3+ years of professional experience in building complex web applications, with a significant focus on frontend development and user-facing systems.

Required Skills:

• Deep expertise in building sophisticated, state-rich user interfaces, particularly with rich text editors like ProseMirror or Tiptap.

• Proven experience in developing real-time collaboration or local-first applications, ideally utilizing Yjs.

• Strong proficiency in TypeScript and modern JavaScript frameworks, with a preference for Next.js.

• Hands-on experience integrating AI/LLM-powered workflows (e.g., with ChatGPT or Claude APIs) into user-facing products.

• Solid understanding of Node.js for backend services supporting frontend features.

• Competence in frontend testing methodologies and tools to ensure application quality and stability.

• Excellent technical judgment for balancing innovation with system stability and reliability.

• Strong collaboration and communication skills, with a proven ability to work effectively with product managers and designers. Preferred Skills:

• Experience with state management libraries and patterns relevant to complex SPAs.

• Familiarity with data visualization techniques for presenting complex benefits data.

• Understanding of backend development principles to support full-stack feature delivery.

• Experience working in a startup environment, particularly within a Y Combinator-backed company.

• Exposure to the insurance or employee benefits industry, understanding its unique regulatory and data complexities.

📝 Enhancement Note: The emphasis on specific technologies like ProseMirror, Tiptap, and Yjs, alongside AI integration, indicates a need for specialized frontend skills. The mention of "operating across the stack" suggests that while UI is the primary focus, a foundational understanding of backend services and how they support frontend functionality is expected for a fullstack role.

📊 Process & Systems Portfolio Requirements

Portfolio Essentials:

• Demonstrations of complex, state-rich UI systems you have architected and built, showcasing intricate state management and user interaction flows.

• Case studies detailing the integration of AI or LLM functionalities into user-facing applications, highlighting the problem solved and the technical approach.

• Examples of real-time collaboration features or local-first application components you have developed, emphasizing synchronization and conflict resolution.

• Projects showcasing your proficiency with TypeScript, modern frameworks (like Next.js), and Node.js, illustrating end-to-end feature development.

• Evidence of robust frontend testing strategies and implementation for ensuring application reliability and performance. Process Documentation:

• Documented workflows for translating product requirements and design mockups into technical specifications and code for complex UI features.

• Examples of how you have approached system design for scalable and maintainable frontend architectures, including considerations for performance and future growth.

• Evidence of iterative development processes, including how feedback from product, design, and clients is incorporated into system improvements.

• Documentation of your approach to integrating third-party APIs (e.g., LLM APIs) and managing their complexities within the application.

📝 Enhancement Note: Given the role's focus on building core product experiences and the company's emphasis on shipping fast and iterating, a portfolio that showcases tangible projects demonstrating ownership, technical depth in UI development, and experience with collaborative/AI features will be highly valued.

💵 Compensation & Benefits

Salary Range: $80,000 - $110,000 USD per year.

This range is competitive for a mid-level Fullstack Engineer with UI specialization in a remote-first startup environment, particularly for roles requiring expertise in specific collaboration and AI technologies. The compensation reflects the high impact and ownership expected in an early-stage company.

Benefits:

• Paid time off (PTO) to ensure work-life balance and employee well-being.

• Learning budget provided to support continuous professional development, skill enhancement, and staying current with emerging technologies.

• Opportunity for significant equity in a fast-growing YC-backed startup.

• Comprehensive health benefits package (details to be confirmed upon offer).

• Professional development opportunities and exposure to cutting-edge AI and SaaS technologies.

Working Hours: Approximately 40 hours per week, with flexibility to accommodate remote work across different time zones within Argentina and Uruguay. The company emphasizes asynchronous communication and results-driven work, allowing for adaptable scheduling.

📝 Enhancement Note: The salary range is provided in USD, indicating that compensation is likely benchmarked against international standards for remote tech talent. The inclusion of a "Learning budget" and "Meaningful ownership" points to a company culture that invests in employee growth and empowers its team members.

🎯 Team & Company Context

🏢 Company Culture

Industry: FinTech / InsurTech / SaaS. Pasito operates at the intersection of AI, enterprise software, and the traditionally slow-moving employee benefits and insurance sector. The company aims to revolutionize this industry by applying modern technology and AI to complex, legacy systems.

Company Size: Early-stage startup, Y Combinator (S22) backed. This implies a dynamic, fast-paced environment where individual contributions have a significant impact. The team is likely lean, agile, and highly collaborative.

Founded: Pasito was founded with the mission to create an AI-native workspace for employee benefits, addressing inefficiencies and complexities in the current system. The company is driven by a desire to make benefits more accessible and understandable.

Team Structure:

• The engineering team is likely composed of early hires with strong technical backgrounds, potentially with a mix of frontend, backend, and AI specialists.

• Reporting structure is expected to be relatively flat, with direct access to founders and senior leadership.

• Cross-functional collaboration is a cornerstone, with engineers working closely with Product, Design, Sales, and Client teams to ensure product-market fit and client success. Methodology:

• Data-driven product development, leveraging user feedback and analytics to inform iterations and new feature development.

• Agile development practices, emphasizing rapid iteration, continuous deployment, and responsive adaptation to market needs.

• Focus on building robust, scalable, and accurate systems, especially critical in the regulated insurance and benefits domain.

• Emphasis on applying AI and LLMs to solve complex problems and automate workflows within the benefits administration lifecycle.

Company Website: https://silver.dev/ (Pasito's product name)

📝 Enhancement Note: The company's YC backing and focus on AI in a legacy industry suggest a culture that values innovation, speed, and technical excellence. The emphasis on building "with" clients, rather than just "for" them, indicates a strong customer-centric approach.

📈 Career & Growth Analysis

Operations Career Level: This role represents a mid-level Fullstack Engineer position with a strong emphasis on UI development. It's an opportunity to step into a foundational engineering role at an early-stage company, offering significant potential for growth as the product and team scale.

Reporting Structure: The engineer will likely report directly to a Head of Engineering or a CTO, with close mentorship and guidance from senior technical leaders and founders. The flat structure encourages direct contribution and visibility.

Operations Impact: The engineer's work will directly impact the core functionality and user experience of Pasito's AI workspace. This includes shaping how complex benefits data is managed, how AI features are utilized, and ultimately, how carriers, brokers, and employees interact with and derive value from the platform. This role has a direct line to revenue enablement through product enhancement.

Growth Opportunities:

• Technical Specialization: Deepen expertise in real-time collaboration, complex UI editors, AI integration, and full-stack development within a high-growth SaaS environment.

• Leadership Potential: As the team grows, opportunities for technical leadership, mentoring junior engineers, and influencing architectural decisions will emerge.

• Domain Expertise: Develop a deep understanding of the employee benefits and insurance industry, a complex and valuable domain for future career development.

• Startup Scale-Up: Gain invaluable experience in scaling a product and engineering team from an early stage to rapid growth.

📝 Enhancement Note: This is a prime opportunity for an engineer who wants to make a significant impact and grow with a company. The "early member" status implies potential for rapid advancement and influence, especially for those who demonstrate strong technical leadership and product ownership.

🌐 Work Environment

Office Type: Fully Remote. The company operates with a remote-first philosophy, allowing engineers to work from anywhere within Argentina and Uruguay.

Office Location(s): While remote, the primary operational focus and talent pool are in Argentina and Uruguay, suggesting potential for informal virtual meetups or regional team gatherings if the company expands its physical presence or hosts events.

Workspace Context:

• A highly collaborative and asynchronous work environment, leveraging modern communication and project management tools.

• Access to cutting-edge technologies and the opportunity to work with AI and LLM integrations in a practical, product-focused manner.

• A culture that values deep work, focused development, and continuous learning, supported by a learning budget.

• Direct interaction with product and design teams, fostering a cohesive development cycle.

Work Schedule: Flexible, with an expected commitment of approximately 40 hours per week. The remote nature and focus on results allow for adaptable scheduling, accommodating personal needs while ensuring project deadlines are met. Asynchronous communication is key, facilitating collaboration across potential time zone differences within the specified regions.

📝 Enhancement Note: The remote-first nature within specific countries is a key aspect. Candidates should be comfortable with asynchronous communication and managing their own work schedule effectively. The emphasis on "AI-native software" suggests a modern tech stack and workflow.

📄 Application & Portfolio Review Process

Interview Process:

• Silver Screening Interview: An initial conversation, likely with a recruiter or HR, to assess basic qualifications, cultural fit, and alignment with the role's core requirements.

• Silver Technical Interview: A deep dive into technical skills, focusing on frontend development, UI architecture, and experience with the specified tech stack (TypeScript, Next.js, ProseMirror/Tiptap, Yjs). Expect coding challenges or architecture discussions.

• Client Screening Interview: This seems to be a unique step, possibly involving a representative from the client company (Pasito, in this case) to assess fit with their specific needs and team dynamics.

• Client Technical Interview: Further technical evaluation, potentially more focused on problem-solving specific to Pasito's product challenges, AI integration, and complex UI scenarios. This might involve a take-home assignment or a live coding session.

• Client Behavioral Interview: Assessment of soft skills, team fit, problem-solving approach, and alignment with Pasito's values and culture. Expect questions about past experiences, collaboration, and how you handle challenges.

Portfolio Review Tips:

• Curate Select Projects: Focus on projects that best demonstrate your UI development skills, experience with complex state management, AI integration, and collaboration tools. If you have direct experience with ProseMirror/Tiptap or Yjs, highlight these prominently.

• Showcase End-to-End Features: For fullstack roles, include examples where you've taken features from concept to deployment, showing both frontend and backend contributions.

• Detail Your Role and Impact: Clearly articulate your specific contributions, the challenges you faced, the solutions you implemented, and the measurable outcomes or impact of your work. Use the STAR method (Situation, Task, Action, Result).

• Technical Depth: Be prepared to discuss the architectural decisions, technology choices, and trade-offs made in your portfolio projects. For this role, expect questions about UI performance, state synchronization, and AI API integrations.

• Visual Appeal: Ensure your portfolio is well-organized, visually appealing, and easy to navigate. A live demo or interactive walkthrough is highly recommended.

Challenge Preparation:

• Technical Challenges: Practice coding problems focused on JavaScript/TypeScript, data structures, algorithms, and complex UI component development. Be ready to discuss performance optimization and state management strategies.

• System Design: Prepare to discuss how you would design scalable and maintainable UI architectures, especially for real-time collaborative applications and AI-powered features.

• Behavioral Questions: Anticipate questions about teamwork, problem-solving, handling feedback, and your motivation for joining Pasito. Connect your answers to the company's mission and values.

• AI/LLM Integration: Be ready to discuss your experience integrating AI models and how you approach challenges related to API usage, data handling, and user experience for AI-driven features.

📝 Enhancement Note: The multi-stage interview process involving both "Silver" (likely the hiring platform/aggregator) and "Client" (Pasito) indicates a thorough evaluation. A strong portfolio showcasing UI-centric fullstack development and AI integration experience is critical for success.

🛠 Tools & Technology Stack

Primary Tools:

• Frontend Framework: Next.js (preferred), modern JavaScript frameworks.

• UI Editors: ProseMirror, Tiptap (deep expertise highly valued).

• Collaboration/Local-First: Yjs (experience highly valued).

• Programming Language: TypeScript, JavaScript, Node.js.

• Version Control: Git.

Analytics & Reporting:

• While not explicitly stated, expect usage of analytics tools (e.g., Google Analytics, Amplitude, PostHog) for tracking user behavior and feature adoption.

• Internal dashboards for monitoring application performance and key metrics. CRM & Automation:

• Likely integration with CRM systems for sales and client management, though specific tools are not detailed.

• Automation tools for CI/CD pipelines and deployment processes.

• Potential use of workflow automation tools for internal operations.

📝 Enhancement Note: The explicit mention of ProseMirror/Tiptap and Yjs is a strong indicator of the core technologies the company is building upon for its rich editing and collaboration features. Proficiency here is a significant differentiator.

👥 Team Culture & Values

Operations Values:

• Precision and Trust: Critical in the benefits and insurance industry, where accuracy and reliability are paramount. Engineers are expected to build systems that inspire confidence.

• Innovation and AI-Native: Embracing AI and LLMs to transform legacy processes and create intelligent workspaces. A culture that encourages experimentation and applying cutting-edge technology.

• Collaboration: Building "with" clients and working closely with internal teams (Product, Design, Sales). A strong emphasis on teamwork and shared ownership.

• Iteration and Speed: Shipping fast, iterating relentlessly, and adapting quickly to market feedback and growth. A dynamic startup environment.

• Human-Centric Design: Ensuring that complex systems are understandable and usable for employees, brokers, and carriers.

Collaboration Style:

• Cross-functional Integration: Engineers are expected to be active participants in discussions with Product and Design, providing technical input and ensuring feasibility.

• Open Communication: A culture that encourages asking questions, sharing knowledge, and providing constructive feedback, likely through tools like Slack and regular team syncs.

• Ownership Mentality: Team members are encouraged to take ownership of their work, drive initiatives, and contribute to the overall success of the product and company.

• Data-Informed Decisions: Utilizing data and user feedback to guide development priorities and validate solutions.

📝 Enhancement Note: The company's values emphasize a blend of technical rigor (precision, trust) with forward-thinking innovation (AI, speed) and a strong collaborative spirit. Candidates should demonstrate alignment with these principles.

⚡ Challenges & Growth Opportunities

Challenges:

• Transforming a Legacy Industry: Applying modern AI and SaaS principles to a complex, regulated, and often slow-moving industry like employee benefits requires adaptability and strategic problem-solving.

• Building Sophisticated UI Systems: Developing and maintaining complex, state-rich editors and real-time collaboration features demands a high level of technical skill and attention to detail.

• Balancing Innovation with Stability: Integrating cutting-edge AI technologies while ensuring the reliability and accuracy required for financial and benefits data is a significant technical challenge.

• Scaling a Fast-Growing Startup: Contributing to the rapid growth of Pasito means adapting to evolving priorities, scaling infrastructure, and potentially onboarding new team members.

Learning & Development Opportunities:

• Advanced UI/UX Development: Gaining deep expertise in real-time collaboration frameworks, rich text editors, and building intuitive interfaces for complex data.

• AI/LLM Integration: Hands-on experience applying AI and LLM technologies to solve real-world business problems in a regulated domain.

• Product Engineering Leadership: Opportunities to shape the product roadmap, influence technical architecture, and potentially lead engineering initiatives as the company scales.

• Industry Knowledge: Developing specialized knowledge in the employee benefits and insurance technology sector, which offers unique career prospects.

• Startup Growth Experience: Learning the dynamics of scaling a tech company from early stages, including product-market fit, team building, and operational efficiency.

📝 Enhancement Note: The challenges presented are directly linked to the company's mission and the nature of the role. Successfully navigating these challenges offers substantial opportunities for professional growth and skill development.

💡 Interview Preparation

Strategy Questions:

• UI Architecture & State Management: "Describe how you would architect a robust, scalable UI for a complex, collaborative editor like Pasito's. What state management strategies would you employ to ensure data consistency and performance?" (Preparation: Review concepts of state management, real-time synchronization, and architecture patterns for complex SPAs. Be ready to discuss ProseMirror/Tiptap and Yjs.)

• AI Integration: "Imagine we need to add an AI feature to summarize benefit plan documents directly within the editor. How would you approach integrating an LLM API, handling data, and presenting the results to the user effectively?" (Preparation: Think about API integration, error handling, data parsing, prompt engineering basics, and user feedback mechanisms for AI features.)

• Collaboration & Ownership: "Tell me about a time you took ownership of a complex feature from start to finish. How did you collaborate with product and design, and what challenges did you overcome?" (Preparation: Use the STAR method to craft a compelling story about a project where you demonstrated initiative and cross-functional collaboration.)

Company & Culture Questions:

• Mission Alignment: "What excites you about Pasito's mission to transform employee benefits with AI, and how do you see your skills contributing to that goal?" (Preparation: Research Pasito's mission, values, and the problem they are solving. Connect your personal career aspirations to their vision.)

• Startup Fit: "How do you approach working in a fast-paced, early-stage startup environment? Describe a time you had to adapt to changing priorities." (Preparation: Highlight your comfort with ambiguity, agility, and a proactive problem-solving mindset.)

• Technical Philosophy: "What are your principles for building high-quality, maintainable UI code, especially in a collaborative environment?" (Preparation: Discuss best practices for code quality, testing, documentation, and collaborative development.)

Portfolio Presentation Strategy:

• Focus on UI Complexity: When presenting your portfolio, emphasize projects where you built sophisticated UIs, managed complex state, or implemented real-time features.

• Highlight AI/LLM Work: If you have relevant AI integration projects, dedicate specific time to explaining the problem, your technical solution, and the impact.

• Demonstrate Fullstack Capability: For each relevant project, clearly articulate your role, showing how you contributed to both frontend and backend aspects, even if your primary focus was UI.

• Quantify Impact: Whenever possible, use metrics and data to demonstrate the success of your projects (e.g., performance improvements, user adoption rates, efficiency gains).

• Storytelling: Frame your project presentations as stories – the problem, your approach, the challenges, and the successful outcome. This makes your contributions memorable.

📝 Enhancement Note: The interview process is structured to assess technical depth, problem-solving skills, and cultural fit. Candidates should prepare to discuss specific technologies and demonstrate how they can apply their skills to Pasito's unique challenges in the benefits industry.

📌 Application Steps

To apply for this Fullstack Engineer position:

• Submit your application through the provided link on jobs.ashbyhq.com.

• Curate Your Portfolio: Select 2-3 projects that best showcase your UI development expertise, complex state management, and any experience with real-time collaboration or AI/LLM integrations. Ensure live demos or detailed case studies are available.

• Tailor Your Resume: Highlight your experience with TypeScript, Next.js, Node.js, and specifically mention any experience with ProseMirror, Tiptap, or Yjs. Quantify your achievements and responsibilities, focusing on UI-centric fullstack contributions.

• Prepare for Technical Deep Dives: Be ready to discuss your approach to UI architecture, state synchronization, performance optimization, and AI integration. Practice coding challenges related to JavaScript/TypeScript and complex UI components.

• Research Pasito: Understand their mission, product, and the challenges they aim to solve in the employee benefits industry. Prepare thoughtful questions for the interviewers about their technology, culture, and future vision.

⚠️ Important Notice: This enhanced job description includes AI-generated insights and operations industry-standard assumptions. All details should be verified directly with the hiring organization before making application decisions.