Fullstack Engineer

JavaScript

Fullstack Engineer

JavaScript
puławska, Warszawa

XPLUS SA

Show all offers
Full-time
Permanent, B2B
Senior
Remote
5 116,19 - 6 193,28 USDNet per month - B2B
4 308,37 - 5 385,46 USDGross per month - Permanent

Job description

We are looking for a Fullstack Engineer to help evolve our runner engine into a powerful internal framework for browser automation, no-code testing, and agentic testing of web applications.

Our product is an end-to-end platform for no-code testing. Users can record workflows, replay them, validate business processes, and automate complex web applications without writing test code. We are also expanding into agentic testing, where AI-driven systems can explore, understand, and test web applications more autonomously.

This role sits at the core of that platform. You will work on the browser automation engine that powers recording, replay, platform integrations, diagnostics, and future AI-assisted testing capabilities.

What You Will Do

  • Expand and evolve our current runner engine into an internal browser automation and testing framework

  • Build reusable TypeScript abstractions over Playwright, Puppeteer, Chrome DevTools Protocol, and browser APIs

  • Improve recording and replay of user actions across complex web applications

  • Develop platform-specific integrations for ERP, CRM, and enterprise systems

  • Support the evolution of our no-code testing platform and agentic web testing capabilities

  • Debug difficult browser automation problems involving timing, dynamic UI updates, frames, custom controls, and SPA behavior

  • Work with Chrome extension architecture where browser-level integration is required

  • Build tooling for diagnostics, traces, logs, screenshots, retries, and failure analysis

  • Use AI tools effectively as part of the engineering workflow to investigate code, debug behavior, and accelerate delivery

  • Write clean, maintainable, strongly typed TypeScript and Node.js code

What We Are Looking For

  • You should have strong TypeScript and Node.js experience, with a solid understanding of the modern JavaScript ecosystem. You should be comfortable building internal frameworks, not just using existing testing tools.

  • We are looking for someone who understands how browser automation really works: how Playwright and Puppeteer interact with pages, how browser contexts and frames behave, how page lifecycle and DOM changes affect automation, and why real user input can behave differently from scripted interactions.

  • You do not need to know every browser internal detail, but you should be able to open DevTools, inspect an unfamiliar web application, understand what is happening, and turn that understanding into reliable framework code.

  • Experience with Chrome extensions, Chrome DevTools Protocol, browser recording/replay systems, custom automation infrastructure, AI-assisted testing, or autonomous web agents is highly relevant.

  • Fluent Polish is a must have.

Bonus Points

  • Understanding of Chromium internals is a strong plus, especially around rendering, processes, frames, input dispatch, site isolation, or browser debugging.

  • Experience with enterprise systems such as Microsoft Dynamics 365, Salesforce, SAP, Oracle, ServiceNow, or Business Central is also valuable.

Tech stack

    Polish

    C1

    English

    B2

    TypeScript

    master

    Node.js

    master

    JavaScript

    advanced

    Playwright

    advanced

    Puppeteer

    advanced

    Chrome DevTools Protocol

    advanced

    ERP

    nice to have

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