Full-Stack Builder

OpenKrill; United States; On-site; USD 90,000 - 140,000; Full time

Benefits offered by this job

Monthly USD payments

23 days PTO per year

USA Federal Holidays

Contractor agreement with no end date

Job summary

Katapult Labs is seeking a skilled Full-Stack Builder to join the founding technical team behind an early-stage partner product—spanning web platform and future mobile app. You will understand and harden the existing architecture, refactor where needed, and seed the technical process for ongoing product development.

The role emphasizes shipping quality features quickly, collaborating with a product-minded team that values user experience, and maintaining lean architectural decisions.

Qualifications

• Strong full-stack engineering experience with modern web technologies (frontend and backend).
• Advanced conversational English and ability to collaborate in a fast-paced startup environment.
• Demonstrated ability to ship quickly with lean architecture and avoid over-engineering.
• Experience refactoring or hardening an existing early-stage codebase.
• Familiarity with product analytics tooling (Amplitude, PostHog or similar).
• Comfort using AI coding tools as part of daily workflow.

Responsibilities

• Understand and evaluate the current architecture of the partner's web platform.
• Refactor and harden the codebase to enable rapid, reliable iteration.
• Build new features end-to-end in collaboration with the product lead on UX and engagement.
• Establish lightweight technical processes (code reviews, deployment, documentation).
• Collaborate with a technical product manager and design lead in a fast-moving startup.
• Extend work into mobile development as the product roadmap evolves.

Skills

Full-stack development

English communication

Shipping fast

Tools

Amplitude

PostHog

Cursor

Claude Code

Job description

About Katapult Labs

Katapult is an AI-first engineering studio connecting senior LATAM talent with startups and companies in the US. We're not a staff-augmentation shop: every person we put in front of a client represents Katapult, co-creates product, and owns the outcome directly, with no managers or leads acting as a layer in between.

The Role

We're looking for a Full-Stack Builder to join the founding technical team behind one of our partners, an early-stage product with big ambitions to become a real tech company: web platform, mobile app, and everything in between. Our partner already has a first version of their site live, built by a non-technical founding team full of product ideas. We need someone who can step in, understand and harden the existing architecture, refactor where needed, and help seed the technical process for building product going forward.

This is a builder role, not a heavy-architecture or platform-engineering seat. You'll move fast, ship with sufficient quality, and work closely with a product-minded team that cares deeply about user experience and engagement. Mobile development isn't required from day one, but the team expects to build a mobile app down the line, so comfort picking that up matters. If the engagement goes well, this grows into a two-builder team supporting the full platform.

KEY RESPONSIBILITIES

• Understand and evaluate the current architecture of our partner's existing web platform
• Refactor and harden the codebase to support rapid, reliable iteration
• Build new features end-to-end, working closely with the product lead on UX and engagement-focused functionality
• Help establish lightweight technical processes (code review, deployment, documentation) as the team scales
• Collaborate directly with a technical product manager and design lead in a fast-moving, startup environment
• Be ready to extend work into mobile development as the product roadmap evolves

REQUIREMENTS

• Advanced conversational English, since all collaboration happens in English
• Strong full-stack engineering experience with modern web technologies (frontend and backend)
• Demonstrated ability to work as a builder: shipping fast, with just enough architecture, not over-engineering
• Comfort working directly with founders and non-technical stakeholders, translating product vision into working software
• Experience refactoring or hardening an existing early-stage codebase
• Product analytics tooling (Amplitude, PostHog, or similar)
• Agentic mindset: comfortable using AI coding tools (Cursor, Claude Code, etc.) as part of daily workflow
• Strong communication skills, comfortable asking clarifying questions and flagging blockers early

NICE TO HAVE

• Prior experience building consumer-facing (B2C) products with high user engagement
• Mobile development experience (native or cross-platform)
• Experience working in a 0-to-1 startup environment alongside a small, fast-moving team

Work-Life Balance

• Work from Anywhere in Latin America: Enjoy the freedom to work remotely from any country in Latin America.
• 23 Days of PTO per Year: Take time to recharge with paid time off, accrued monthly (1.91 days/month).
• USA Federal Holidays

Financial Benefits

• Monthly Payment in USD: Get paid in US dollars, no matter where you are.
• Contractor Agreement with No End Date: Enjoy the stability of a long-term contract.