Svelte UI Developer (f/m/x)

Senior • Remote

14,400 - 27,200 PLN

Warsaw, Poland

We develop our product offering to help wealth management to serve their clients' portfolios. For this, we build scalable solutions that need to perform with a rich history of financial data. We specialize in being breadth of offerings to support smaller firms' needs to serve their users well with a highly configurable solution with many functions.

Our platform has been built over years of experience in the portfolio management domain. We enhance business functionalities as well as strengthen our technology to scale operationally with low cost of ownership and high quality. For this work, we are looking for further Software Engineers to become full members of our team and take the tasks at hand from the Scrum backlog.

Your tasks

Design and develop front-end components and windows for IPT/IOM trading workflows using modern Svelte / SvelteKit, with a focus on real-time responsiveness, interoperability and minimal latency
Write testable, maintainable code with appropriate unit and component-level tests, and contribute to the team’s continuous integration pipelines
Apply modern tooling and champion clean-code and performance standards across the front-end codebase
Contribute to code reviews and help raise the team’s engineering standards around component architecture, accessibility, and maintainability
Integrate UI components with IPT/IOM back-end services and other upstream/downstream trading systems via REST, WebSocket, and messaging APIs
Iterate rapidly — prototype, refine, and ship new features on tight timelines, working directly with traders and squad stakeholders to validate behaviour
Operate on Linux: shell navigation, log inspection, process control, and remote workflows
Provide front-line support for UI issues in production trading installations, diagnosing problems quickly and delivering fixes with minimal disruption to live trading
Act as a close partner to back-end engineers, product owners — translating operational feedback into concrete UI/UX improvements
Champion UX quality by applying strong usability, layout, and interaction judgment to data-dense, high-frequency-use interfaces

Requirements

Solid hands-on, more than 5 years of experience building production applications with Svelte (and/or SvelteKit), including component architecture, stores, reactivity, and lifecycle management
Strong command of modern HTML, CSS, and JavaScript/TypeScript, along with browser APIs, async patterns
Demonstrable sensitivity to usability, layout, and interaction design — particularly for data-dense, high-frequency-use professional interfaces
Comfortable with basic Linux operations — shell navigation, package management, log inspection, process control, and remote development workflows
Fluent English, both written and spoken
Polish at a communicative level

Sii

Sii is a company recognized as a "Great Place to Work" since 2015, thanks to employee feedback and the implementation of new ideas. Established in 2006, Sii has demonstrated financial stability with a revenue of 2.1 billion PLN and no debts. The company shares its profits with employees, having allocated over 76 million PLN for this purpose since 2022. Sii offers a rich benefits package, including private healthcare, a cafeteria platform, and discounts on cars. Employees can work in comfortable A-class offices or remotely. Sii is involved in numerous fascinating projects for prestigious global brands and invests 1 million PLN annually to support employee passions and volunteer actions. The company emphasizes personal development through meetups, webinars, a training platform, and a technology blog. Sii is characterized by a fantastic atmosphere created by its "Sii Power People."

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