Upgrade Post project
Profileimage by Jrme Weiss React Full Stack Developer from Berlin

Jérôme Weiß

Berlin
available

Last update: 19.02.2024

React Full Stack Developer

Graduation: Fullstack Developer
Hourly-/Daily rates: show
Languages: German (Native or Bilingual) | English (Full Professional)

Keywords

Attachments

CV-Jerome-Weiss_190224.pdf

Skills

Professional Statement
Always cheerful React Fullstack Developer who specializes in scalable web applications and supports the Node.js stack. His background in architecture helps him now with producing clean and maintainable code. He enjoys working in an Agile team that practices pair programming with a test-first approach (TDD)

Key Skills
FRONTEND: React, Redux, Router, Bootstrap, JavaScript, TypeScript, i18n, a11y, Webpack, HTML, CSS
BACKEND: Next.js, REST, Node, Serverless, Express, Knex, Swagger, NoSQL, PostgreSQL, SSR, Microservices
TDD: Test-first Automation, Mocking, e2e Testing, Jest, Cypress, CodeceptJS, Testing Library, Storybook
DEVOPS: CI/CD, IaC, AWS, cfn, Jenkins, CircleCI, GitHub Actions, Artifactory, Feature Toggling, Docker, Git
AGILE: XP, Scrum, Kanban, User Stories, INVEST, Pair Programming, A/B Testing
LANGUAGES: English (fluent), German (native)

Project history

04/2023 - Present
Improved the security of two native health apps according to strict legal requirements to allow a certification as Digital Health App
(Other, 10-50 employees)
CLIENT
Provider of digital health apps

SKILLS
React, Next.js, TypeScript, Formik, Emotion, FeathersJS, REST, Node, Mongoose, MongoDB, Cypress,
Jest, GitHub Actions, Docker, Kubernetes, Telekom Cloud, Sentry, Flutter, Dart, iOS, Android, Kanban

ACHIEVEMENTS AND RESPONSIBILITIES
- Improved the security of two native health apps according to strict legal requirements to allow a
certification as Digital Health App (DiGA) by the Federal Institute for Drugs and Medical Devices (BfArM)
- Developed a new Next.js-based admin app to manage users, user consents, access codes, and to provide
business insights into the usage of the app and different features
- Implemented legal requirements to make the apps compliant with federal data protection law (DSGVO)
- Improved a responsive Flutter app for iOS and Android with backend integration, offline mode, biometric
security, auth & account management flows, PDF preview, file picker, notifications, and much more
- Maintained a FeatherJS- and MongoDB-bases based backend and a Next.js app for account management
- Eliminated the need to check for and fix security vulnerabilities with Dependabot manually
​​​​​​​- Reduced the risk of corrupt databases by introducing server-side validation, transactions, and migrations
11/2022 - 05/2023
Development of the official e-commerce web app to find and buy sports cars based on Next.js
(Automotive and vehicle construction, 500-1000 employees)
CLIENT
German luxury sports cars manufacturer

SKILLS
Next.js, React, Styled Components, TypeScript, REST, AWS, CI/CD, CodePipeline, GitHub Actions, Docker, Storybook, TDD, Jest, Cypress, Testing Library, Git, Matomo, Scrum

ACHIEVEMENTS & RESPONSIBILITIES
- Development of the official e-commerce web app to find and buy sports cars based on Next.js
- Improved the React app while satisfying numerous country-specific requirements
- Refactored a complicated React component to showcase multiple car images by applying the Single Responsibility Principle (e.g., hiding the complexity of the underlying non-React library in a custom hook and using another custom hook to integrate the component into the routing system of the app)
- Spearheaded an initiative to reduce the huge amount of console errors while running the test suite and coached the team on React Testing Library best practices
10/2022 - 11/2022
Implemented a sign-up wizard for club guests with TypeScript and Next.js
(Other, 500-1000 employees)

CLIENT
International chain of premium fitness clubs

SKILLS
Next.js, React, JavaScript, REST, Node, PostgreSQL, Jest, Testing Library, Git, Kanban


ACHIEVEMENTS & RESPONSIBILITIES
- Implemented a sign-up wizard for club guests with TypeScript and Next.js
- Reduced the amount of boilerplate form and validation logic by using React Hook Form and Zod
- Created a microservice to abstract away more complex edge cases from the frontend
- Separated request handling, business logic, and integration of 3rd-party APIs with a layered architecture

07/2020 - 09/2022
Developed a suite of premium web application products to streamline the process of buying a house
(Internet and Information Technology, 500-1000 employees)
CLIENT
Germany's leading online market place for real estates

SKILLS
React, Redux, TypeScript, REST, Express, PostgreSQL, AWS, cfn, Storybook, Jest, Testing Library, Cypress, Playwright, CI/CD, Jenkins, GitHub Actions, Git, ScrumBan

- Developed a suite of premium web application products to streamline the process of buying a house
- Helped grow the revenue from 1.3M EUR in the first year to 10M EUR in the third year (based on 30,000 paying subscribers)
- Consulted several teams on re-writing legacy fronted apps using a modern tech stack and DevOps best practices
- Conducted knowledge sessions to share React Testing Library best practices with other teams
 

GENERATOR FOR A PROFESSIONAL APPLICATION PORTFOLIO
- Spear-headed a complex architectural application change over several projects after major compatibility-breaking change in the popular React library react-router
- Helped team negotiate their poor design decision with answers to how and where to handle errors, asynchronous side effects, and more complex business logic
- Inherited a legacy payment project with outdated code that needed urgent adjustments and improved the code quality and coverage from 50% to 90% over the course of 3 months
- Used Test-first Programming to drive the development of the frontend and Storybook to create components more efficiently in isolation according to the designs provided by the UX designer
- Reduced build time of a backend project from 10 minutes to 2 seconds by migrating the project from Webpack to esbuild
- Paired with 6 developers on vertically sliced User Stories and consulted the Product Owner on how to create good User Stories

PROPERTY VALUATION (SPRENGNETTER)
- Reimplemented a property valuation flow as a stand-alone wizard (micro-frontend) that now can be integrated by other departments
- Implemented an accessible video player component with hidden controls for showing ads
- Maintained a Serverless backend with a DynamoDB hosted with AWS Lambda and AWS API Gateway
- Introduced test and storybook decorators to make testing React components easier and faster
- Upgraded a CI/CD pipeline used by hundreds of software engineers to deploy a mission-critical service

ASSESSMENT OF STRUCTURAL PROPERTY DAMAGES (DEKRA)
- Developed a React app to evaluate structural property damages with the help of an API provided by DEKRA • Mobile-first responsive web design using clean layout techniques and a bootstrap-like styling library
- Helped migrate the images of several projects from PNG to responsive WebP images using Webpack
- Created e2e test suites with Cypress and Playwright and improved the error output with custom reporters • Rolled out new features to end-users gradually using Optimizely feature toggles and A/B tests

DASHBOARD TO MANAGE AND OPTIMIZE MORTGAGE PAYMENTS
- Refactored shared class-based React components (such as wizards, modals, and carousels) to functional React components using custom hooks
- Increased the accessibility (a11y) of several apps by migrating Enzyme tests to React Testing Library and testing frontend components through the „eyes“ of the end-users
- Migrated a Java-based microservice to Express and added PostgreSQL schema migrations using Knex
- Acted as DevOps Support of the Week monitoring the team’s systems and reviewing 3rd-party pull requests

CREDIT SCORE CERTIFICATE (SCHUFA)
- Added page and event tracking of user activities with Google-Analytics-like service
- Fine-tuned flaky e2e tests that started failing due to race conditions after migrating to faster hardware
- Helped the team to stay focused by facilitating Agile ceremonies, including Retrospective, Daily Standup, and Iteration planning

04/2020 - 06/2020
Responsive React App for Mastery Tracking
(Internet and Information Technology)
CLIENT
Educational institutions

SKILLS
React, Redux, Bootstrap, JavaScript, AWS, REST, Serverless, Swagger, DynamoDB, Storybook, Jest, Enzyme, Codecept, CircleCI, Agile


ACHIEVEMENTS & RESPONSIBILITIES
- Developed a single-page SaaS application with a clean architecture that separates frontend components (React), central application state (Redux), and asynchronous state transitions (Thunks)
- Used a test-first approach to drive the implementation with acceptance, integration, and unit tests
- Implemented reusable react components such as wizards, modals, carousels, and input components
- Shipped new features on a daily basis using continuous delivery with CircleCI, AWS, and NPM Scripts
- Created a localized app experience with the help of i18n-libraries like react-intl and i18next
- Maintained an Express-based mock API to enable local development of the React frontend
- Collaborated closely with Product Owner to respond to continuously changing & increasing project scope

Local Availability

Only available in Berlin and 50 km around
- available worldwide for remote roles
- available on-site in Berlin for up to 100%
- available on-site outside of Berlin for up to 10%
- happy to visit clients all across Europe every other week (e.g., to collect feedback and discuss requirements)
Profileimage by Jrme Weiss React Full Stack Developer from Berlin React Full Stack Developer
Register