Mid-Level UI Developer
Immediate
AWSDockerJavaScriptJenkinsNext.jsNode.jsPHPReactSCSSWebpackWordPressYarn
Senior Frontend Developer
Cornspring
full-time
Posted on:
Location Type: Hybrid
Location: London • New York • 🇺🇸 United States
Visit company websiteJob Level
Senior
Tech Stack
CloudJavaScriptReactTypeScript
About the role
- You will be responsible for developing sophisticated data manipulation interfaces using TypeScript within the Microsoft Office Add-in ecosystem while also creating intuitive web applications where clients interact with their data using AI.
- Design, build, and maintain high-performance Excel Add-ins using TypeScript and Office.js, tailored for internal Microsoft 365 deployment.
- Develop and scale web interfaces for AI solutions, data visualization, and reporting.
- Work closely with our Backend team to ensure seamless integration with our cloud services while delivering exceptional user experiences in both Excel and our React-based web portal.
- Contribute to architectural decisions, component libraries, and development best practices.
- Support cross-team coordination around security, testing, deployment, and CI/CD pipelines.
- Report to the Head of Platform Development and collaborate with a team of mission-driven engineers.
Requirements
- You must have the right to work in the location you're applying for - no visa sponsorship can be provided.
- This role is perfect for someone who enjoys building robust user experiences that bridge traditional productivity tools (like Excel) with modern, responsive web apps; and who is excited by the opportunity to work with AI and financial data.
- This role requires deep understanding of data visualization, REST API integration, and responsive design principles.
- You will need professional frontend development experience with JavaScript, React and TypeScript.
- Strong expertise in modern UI development practices.
- Proven experience building and deploying Office Add-ins, especially within Microsoft 365 for internal enterprise use.
- Deep knowledge of the Excel JavaScript API, object models, and data handling within workbook constraints.
- Comfortable integrating with REST APIs, handling authentication flows (e.g., OAuth), and managing async data interactions.
- Strong understanding of frontend performance optimization, state management, and cross-environment compatibility.
- Experience working in Agile teams, with a proactive and ownership-driven mindset.
Benefits
- Competitive salary.
- Hybrid working: we come to the office 2/3 days a week (Bank, in London / Manhattan, in New York).
- Being part of a revolutionary movement in Family Office technology.
- Working with cutting-edge AI and data technologies.
- Challenging projects that make a real impact to our sector.
Applicant Tracking System Keywords
Tip: use these terms in your resume and cover letter to boost ATS matches.
Hard skills
TypeScriptJavaScriptReactExcel Add-insOffice.jsdata visualizationREST API integrationfrontend performance optimizationstate managementresponsive design
Soft skills
proactive mindsetownership-drivencollaborationcross-team coordinationexceptional user experience
