April 8, 2026

Senior Frontend Developer (Part-time; 100% remote)

Senior • Remote

100 - 145 USD/hr

Warsaw, Poland

Senior Frontend Developer (Part-time; 100% remote)

  • 💰Salary: up to around $40 per hour

  • 💻 100% Remote

  • 🕦 Part-time: Around 10h per week, up to 10-15h/week, as needed

  • ☑️ B2B contract/freelance

  

We are seeking a Senior Front-End Developer to work on the ongoing improvement, maintenance, and optimization of our extensive public-facing website. The role is focused on working with an existing, production-grade codebase built primarily with HTML, CSS, JavaScript, PHP and WordPress, under CloudFlare.

Requirements

  • Expert-level experience in front-end development, with a strong track record of working on long-lived or legacy codebases

  • Website performance optimization experience, web performance tooling and audits (e.g., Lighthouse, Google PageSpeed insights) experience.

  • Ability to work independently (along with a work history of independent work)

  • Excellent knowledge of JavaScript, HTML and CSS, with a clear understanding of responsive design principles

  • Basic understanding of SEO fundamentals, including performance factors, and search-engine-friendly markup

  • Experience working with extensive and legacy frontend systems

  • Strong attention to detail and a quality-focused mindset

Main Responsibilities

  • Optimize page load times and overall website performance using front-end techniques.

  • Working on bugfixes and optimization of a legacy front-end website built with JavaScript, HTML, CSS, and WordPress, ensuring performance, and stability.

  • Improve existing features and user-facing functionality through thoughtful, incremental enhancements rather than full rewrites.

  • Collaborate with internal developers, designers, management, and content teams to implement updates and refinements to existing pages and components.

  • Ensure cross-browser compatibility across the website.

  • Apply front-end SEO best practices, including performance optimization (most importantly), accessibility improvements, page structure, and Core Web Vitals.

Get to know DevsData:

We are a technology consulting company and a recruitment agency, delivering software solutions to clients from Europe and the US. We work 100% remotely, in an international team, including people from Asia, London, or San Francisco. We employ people with experience in international corporations as well as students of the best technical and business universities. Find out more: https://devsdata.com/

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