Senior Web Developer: SDK & Design System Lead (Remote)

Yuno; Madrid; On-site; EUR 70,000 - 90,000; Full time

Benefits offered by this job

Competitive Compensation

Remote Work

Home Office Bonus

Work Equipment

Stock Options

Health Plan

Flexible Days Off

Growth Courses

Job summary

Yuno is seeking a Senior Web Developer to build the SDK, design system, and web components powering third‑party integrations with our AI‑native payments platform.

You will own the developer-facing surface of Yuno's single API, delivering reusable components and SDKs across browsers and environments, with a strong focus on developer experience and performance. Remote work option available for Europe/Latam teams.

Qualifications

• 5+ years building production applications with React, JavaScript, and TypeScript.
• Solid command of the modern web stack – Node, CSS, Next.js, Storybook, and Emotion.
• Engineering fundamentals – OOP, Git, unit and E2E testing, and CI/CD.
• Build and packaging tooling (NPM/ yarn), with an eye for bundle size and performance.
• AWS (S3, Amplify) and Docker.
• AI-assisted development – fluent use of tools like ClaudeCode, Cursor, or GitHub Copilot, and leveraging LLMs across design, implementation, debugging, testing, documentation, and code reviews.
• Autonomy and agile delivery – you own tasks end to end and work comfortably in SCRUM.
• English – advanced proficiency, written and spoken.

Responsibilities

• SDK and design system – create the design system and web components used across third-party applications, ensuring SDK compatibility across browsers, frameworks, and integration environments.
• Cross-platform consistency – collaborate with backend and mobile teams so the SDK behaves consistently across every platform and integration.
• Performance and build optimization – design low-latency, high-availability applications and optimize bundle size, tree-shaking, and build performance for SDK distribution.
• Full-stack integration – connect user-facing elements with server-side logic and integrate data storage solutions into cohesive, reliable systems.
• Code quality and security – write reusable, testable, and efficient code, and implement security and data protection throughout.
• Developer experience and releases – maintain high-quality documentation and DX for integrators, and design automated pipelines for publishing and versioning SDK releases.

Skills

React

JavaScript

TypeScript

Node.js

CSS

Next.js

Storybook

Emotion

OOP

Git

Unit testing

E2E testing

CI/CD

NPM/Yarn

AWS

Docker

AI-assisted development

SCRUM

English (advanced)

Tools

AWS

Docker

Job description

Yuno is seeking a Senior Web Developer to build the SDK, design system, and web components powering third‑party integrations with our AI‑native payments platform.

You will own the developer-facing surface of Yuno's single API, delivering reusable components and SDKs across browsers and environments, with a strong focus on developer experience and performance. Remote work option available for Europe/Latam teams.