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- Tasks: Develop cutting-edge Excel Add-ins and AI-driven web applications using TypeScript and JavaScript.
- Company: Join Cornspring, a dynamic start-up revolutionising Family Office services with innovative tech and data management.
- Benefits: Enjoy flexible work hours, remote options, and opportunities for professional growth in a collaborative environment.
- Why this job: Be part of a mission-driven team creating impactful projects at the intersection of finance and AI.
- Qualifications: Proven experience in front-end development, particularly with JavaScript, React, and Excel Add-ins.
- Other info: Candidates must be based in the UK and have the right to work without sponsorship.
The predicted salary is between 43200 - 72000 £ per year.
Cornspring is a dynamic start-up developing Family Office services through a unique combination of innovative technology and data management excellence. Our platform leverages state-of-the-art generative AI and large language models to provide unparalleled insights and efficiency to Family Office investment and accounting data. We pride ourselves on fostering a collaborative and inclusive work environment where we prize creativity, excellence in engineering, a powerful customer focus and attention to problem-solving through great design.
We are seeking an experienced Front-end Developer to join our team, focusing on building our Excel Add-in solutions and web portal platform. 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. This role requires deep understanding of data visualization, REST API integration, and responsive design principles. You will work closely with our back-end team to ensure seamless integration with our AWS services while delivering exceptional user experiences in both Excel and our React-based web portal.
We’re looking for a Senior JavaScript / TypeScript Developer who thrives at the intersection of elegant UI development and advanced Excel Add-in engineering. You’ll lead development on two core user-facing components:
- Our AI-driven web platform, built using JavaScript, React and TypeScript
- Our Excel Add-in, deployed internally within Microsoft 365, integrating directly with our platform APIs
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.
Key Responsibilities
- 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 our AI solutions, data visualization, and reporting
- Collaborate with backend engineers to connect APIs, manage state, and streamline data integration
- Ensure excellent UX in both browser and Excel environments, with intuitive, performant, and consistent interfaces
- Contribute to architectural decisions, component libraries, and development best practices
- Support cross-team coordination around security, testing, deployment, and CI/CD pipelines
What We're Looking For
- Professional front-end 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 front-end performance optimization, state management, and cross-environment compatibility
- Experience working in Agile teams, with a proactive and ownership-driven mindset
Bonus Points For
- Experience with data-intensive applications or financial tools
- Familiarity with data visualization libraries (e.g., D3.js, Chart.js, Recharts)
- Knowledge of Microsoft Graph API and M365 deployment configurations
- Exposure to AWS services (Lambda, API Gateway, Cognito, etc.)
- Understanding of AI and LLM patterns for chat, collaboration or search interfaces
What We Offer
- Work with cutting-edge AI and data technologies.
- Collaborate with a small, high-calibre, mission-driven team
- Opportunities for professional growth and development.
- Flexible work hours and remote work options.
- Engaging and challenging projects that make a real impact to our sector.
- Fast-paced, deeply impactful work with real users and rapid iterations
Important Application Criteria
To ensure we make the best use of your time and ours, please review the following before submitting your application. This role is suited to candidates who:
- Are based in the UK and able to work effectively with a London-based team
- Have the unrestricted right to work in the UK – note that we are currently not able to offer visa sponsorship
- Bring proven experience in both modern UI development and Excel Add-in engineering in data-centric or enterprise environments
- Operate confidently at a senior level, capable of contributing to architectural decisions and working autonomously in a fast-moving setting
Candidates passing initial review will be asked to undertake a skills assessment. We value thoughtful, relevant applications and will prioritise those that clearly align with the requirements outlined above. If this sounds like the right fit for your background and ambitions, we’d be delighted to hear from you.
How to Apply
Send us your CV and (optionally) GitHub/portfolio, along with a short note on your experience with Excel Add-ins, UI development, and what excites you about this role.
Senior JavaScript / TypeScript Developer employer: Cornspring
Contact Detail:
Cornspring Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Senior JavaScript / TypeScript Developer
✨Tip Number 1
Familiarise yourself with the latest trends in JavaScript and TypeScript, especially focusing on frameworks like React. This will not only enhance your technical skills but also show your commitment to staying updated in a fast-evolving field.
✨Tip Number 2
Engage with the developer community by participating in forums or attending meetups related to Excel Add-ins and UI development. Networking can lead to valuable insights and connections that may help you during the application process.
✨Tip Number 3
Prepare to discuss your previous projects involving Office Add-ins and data visualisation. Be ready to explain your thought process and the challenges you faced, as this will demonstrate your problem-solving abilities and experience.
✨Tip Number 4
Showcase your understanding of REST APIs and how they integrate with front-end applications. Being able to articulate your experience with API integration will set you apart as a candidate who can bridge the gap between front-end and back-end development.
We think you need these skills to ace Senior JavaScript / TypeScript Developer
Some tips for your application 🫡
Tailor Your CV: Make sure your CV highlights your experience with JavaScript, TypeScript, and Excel Add-in development. Emphasise any relevant projects or roles that showcase your skills in UI development and data manipulation.
Craft a Compelling Cover Note: In your cover note, briefly explain your passion for building user-friendly interfaces and your experience with AI technologies. Mention specific projects that relate to the job description, particularly those involving Excel Add-ins and data visualisation.
Showcase Relevant Work: If you have a GitHub or portfolio, include it in your application. Highlight projects that demonstrate your expertise in modern UI practices and Office Add-in development, especially those that involve REST API integration.
Align with Company Values: Research Cornspring's values and mission. In your application, reflect on how your work ethic and approach to problem-solving align with their focus on creativity, collaboration, and customer-centric design.
How to prepare for a job interview at Cornspring
✨Showcase Your Technical Skills
Be prepared to discuss your experience with JavaScript, TypeScript, and React in detail. Bring examples of previous projects, especially those involving Excel Add-ins or data visualisation, to demonstrate your expertise.
✨Understand the Company’s Vision
Research Cornspring and their focus on AI and data management. Be ready to explain how your skills can contribute to their mission of providing innovative Family Office services.
✨Prepare for Problem-Solving Questions
Expect questions that assess your problem-solving abilities, particularly in UI development and data integration. Think through scenarios where you had to overcome challenges in past projects and be ready to share your thought process.
✨Demonstrate Collaboration Skills
Since the role involves working closely with back-end engineers, highlight your experience in collaborative environments. Share examples of how you’ve successfully worked in Agile teams and contributed to architectural decisions.
