Patryk Pozniak

Senior Frontend Developer | Software Engineer

Ownership-driven software engineer with 10 years of experience, specializing in frontend while maintaining a broad engineering perspective. Focused on architecting accessible, high-performance applications and improving developer experience. Passionate about mentoring and delivering robust, reliable solutions from end to end.

Technical Skills

Core Engineering & Standards

  • TypeScript & JavaScript
  • Web Accessibility (WCAG)
  • Modern CSS & Responsive Design
  • Architecture: SPA, SSR, SSG
  • Design Systems & Storybook

Frontend Ecosystem

  • React & Next.js
  • Vue.js & Svelte
  • State Management (Redux, Context, SWR)
  • Tailwind CSS, SASS, Styled Components
  • MJML (Email Templating)

Backend & Infrastructure

  • Node.js
  • AWS (Lambda, S3, DynamoDB, CDK)
  • CI/CD & DevOps
  • Headless CMS (Sanity, Commercetools)
  • API Design (REST, GraphQL)

Quality & Engineering Ops

  • E2E Testing (Playwright)
  • Unit & Integration (Jest, Vitest, MSW)
  • Visual Regression (Chromatic, BackstopJS)
  • Performance & Web Vitals Optimization
  • Technical Design & Documentation

Experience

Senior Frontend Developer at Slice

Mar 2026Present
    ReactNext.jsTypeScriptJavaScript

    Senior Frontend Developer at Voy

    Jun 2024Mar 2026
    • Architected the refactoring of the pricing service: Designed the new batch API contract, wrote the solution design, and led the frontend team to deliver a unified architecture.
    • Led the frontend implementation of 'Longer Plans' (3/6/12-month subscriptions), a high-impact revenue project involving complex pricing logic and close collaboration with backend engineering.
    • Developed core features for the weight loss platform, including interactive timelines and photo comparisons to improve user engagement.
    • Managed A/B testing experiments (ABTasty, Posthog) for a high-traffic platform, optimizing features based on data from thousands of daily users.
    ReactNext.jsTypeScriptSWRAWSABTastyPosthogSanity CMSTechnical documentation

    Senior Frontend Developer at Omnevue

    Feb 2023Jun 2024
    Reason for leaving: redundancy
    • Rapidly prototyped an MVP for a carbon emissions estimation tool with graph features and Plaid integration, eventually managing both frontend and backend contributions including Lambda schedulers and API endpoints.
    • Led a major application update for 'business groups,' managing extensive frontend updates and collaborating with backend engineers to plan and execute all related tickets.
    • Integrated HubSpot CRM into the platform, implementing data synchronization within existing AWS Lambdas to manage CRM entities.
    • Established a dedicated repository and CI-based release process for email templates (MJML), making template additions and modifications straightforward.
    • Implemented unit testing with Vitest and Mock Service Worker (MSW), and authored a comprehensive Notion guide featuring technical how-tos and tips.
    VuePlaywrightVitestAWS CDKMJMLFigmaHubSpotPlaidWordpress

    Frontend Developer at Sproutl

    Nov 2021Jan 2023
    Reason for leaving: redundancy
    • Led extensive SEO and UX improvements, successfully decreasing site error counts by more than 2,000.
    • Solo developed a custom Commercetools application for order management to simplify and reduce error rates in exception handling.
    • Migrated legacy Python code into TypeScript to standardize team responsibility and improve development velocity.
    • Planned and executed a 'back in stock' email flow, which included writing custom cloud functions.
    ReactTypeScriptNode.jsNext.jsSanity CMSGCPStyled-componentsCommercetoolsIterableSendgridTerraform

    Full-stack Developer at InYourArea

    Sep 2020Nov 2021
    • Initiated a 'v2' frontend repository focusing on better typings, tests, performance, and developer experience.
    • Executed a new version of the local news dashboard, consolidating multiple content types into a unified interface.
    • Solo built a scheduled spreadsheet-to-database data transfer and normalization service to automate content team workflows.
    ReactTypeScriptFlowAWSReduxNode.jsMongoDBStorybookSASSWebpack

    Software Engineer II at Moo

    Feb 2020Aug 2020
    Reason for leaving: redundancy
    • Led UX improvements by working closely with the UX/UI team and conducting user testing to refine the customer journey.
    ReactFlowPythonReduxChromaticBackstopGitlab CIStorybook

    Frontend Developer at Yoti

    Oct 2018Feb 2020
    • Directed the refactoring of a password manager extension, resulting in a 2.6MB size reduction and improved runtime performance.
    • Conducted documented research on best practices to justify and implement frontend standards across the company community.
    • Overhauled the unit testing approach, leading to an increase in early bug detection.
    • Developed a modular, high-performance identity confirmation application, collaborating closely with PMs and mobile developers.
    ReactPreactWebpackBrowser Extension APIReact-routerjs-lingui (i18n)react-testing-library

    Frontend Developer at apptimia

    Dec 2017Apr 2018
    • Rapidly solo developed two cross-platform room booking applications in React Native for Android and iOS.
    • Collaborated within a small team on an IoT application, maintaining close interaction with backend developers for integration.
    ReactReact-nativeReduxRedux-thunkStyled-componentsSASS

    Frontend Developer at Squiz

    Nov 2015Nov 2017
    • Created accessible (WCAG) web applications for banking and government clients using Matrix CMS.
    • Graduated from the internship program with the highest score and later trained new interns on JavaScript fundamentals.
    • Managed weekly support rotations, resolving bugs across a wide variety of legacy and modern systems.
    HTMLCSSSASSJSjQueryWCAGGulpWeb Audio APIGoogle Maps API

    Education

    IT Technician at ZSEE / TME - Poland, Szczecin

    • 4-year Vocational Technical High School program specializing in Computer Science.
    • Earned the professional title of IT Technician after passing national state examinations.
    • Curriculum included hardware maintenance, network administration, and software development.
    HTMLCSSJavaScriptC++SQLDatabasesNetworkingHardware

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