Daniel Kremniov
Verified Expert in Engineering
React Developer
Vilnius, Vilnius County, Lithuania
Toptal member since March 29, 2022
Daniel is a front-end engineer with over 10 years of commercial experience working for several UK and worldwide clients across the marketing, travel, insurance, and finance industries. He specializes in sophisticated single-page front-end application development using React and TypeScript with an emphasis on testable architecture. Daniel's clients describe him as a developer with an excellent eye for detail who can work well alongside other people.
Portfolio
Experience
Availability
Preferred Environment
Azure DevOps, Agile, MacOS, Git, WebStorm, Jira
The most amazing...
...React application I've been reengineering is the Blockchain.com crypto wallet with more than half a million daily users and over 37 million verified accounts.
Work Experience
Staff Front-end Engineer
Blockchain
- Maintained a web crypto wallet with more than half a million daily users and over 37 million verified accounts.
- Rebuilt the most revenue-generating features of the wallet, improving the overall front-end architecture, introducing testing best practices, and mentoring other team members.
- Hosted recurring front-end guild meetings for a team of 12 developers to promote high code standards and identify/resolve common impediments.
- Collaborated closely with back-end engineers to define the REST API for the project and ensure adherence to the contract between front end and back end.
Senior Front-end Engineer
Vyne
- Delivered a greenfield React application for automated merchant onboarding in an agile startup environment.
- Reviewed, proposed, and implemented architecture improvements for a business-critical checkout flow written in Next.js and TypeScript, used by clients including Wix, WooCommerce, Salesforce, and Big Commerce.
- Enhanced the developer workflow by introducing tools for API substitution in the local environment and automatic code generation.
- Contributed to three different codebases written in Angular.
Senior Front-end Engineer
Moody's
- Developed highly interactive single-page applications with sophisticated business logic, allowing users to optimize their investment strategies using underlying Moody's products.
- Led the delivery of a highly interactive greenfield React application that assists insurers in building optimal liability-aware investment portfolios using TypeScript, React, and Apollo.
- Acted as a hands-on front-end technical lead. Managed communication with key stakeholders, resolved cross-team dependencies with two separate back-end teams, and ensured the front-end team delivered critical features with quality and timeliness.
- Created a testable front-end architecture and a clear testing strategy for the project.
- Helped the back-end team in defining a well-optimized GraphQL schema for front-end consumption.
- Actively maintained a mono-repo with reusable components used by 10 other front-end applications.
- Organized the teamwork and the application deployment on the Azure DevOps platform.
Founder and Team Lead
Right Thinking
- Built and led my own remote worldwide team of four front-end engineers.
- Managed communication with several clients and assigned work to my team.
- Delivered applications of varying complexity using the TypeScript, React, Redux, and Apollo stack.
Lead Front-end Engineer
Icelolly Marketing
- Improved the performance of an existing customer-facing website by 30%, eliminating common performance bottlenecks and optimizing the critical rendering path.
- Migrated the web application from a monolithic PHP to a standalone React server-rendered architecture using a custom Node.js and Webpack setup.
- Increased overall conversion by over 20% by implementing numerous successful A/B tests in close collaboration with business stakeholders and a design team.
- Led technical vision of a team of three front-end engineers.
Web Engineer
CPP Group
- Delivered a greenfield user management project using React and Redux in an agile environment.
- Created a shared library with reusable components and style guidelines for future branded projects.
- Maintained and developed new features for an existing AngularJS application.
Front-end Developer
Blueclaw Media
- Delivered highly interactive and responsive websites for the sports and marketing industries using HTML, CSS, and JavaScript.
- Worked closely with back-end and design teams, as well as other business stakeholders.
- Contributed to the user experience SEO strategies.
Front-end Developer
Visual & Softworks
- Delivered medium-sized projects using HTML, CSS, and Vanilla JavaScript.
- Collaborated closely with back-end developers and the creative team.
- Gained valuable experience in project management and face-to-face communication with clients.
Experience
Blockchain.com Crypto Wallet
The business recently had a huge growth and the codebases needed a significant engineering effort to keep up with the pace. I was completely rebuilding most revenue-generating features, improving overall front-end architecture. Also, I introduced testing and mentored other team members on further scaling of the application.
Open Banking Powered Payments Platform
https://payvyne.com/I was carefully reviewing, proposing, and implementing architecture improvements for a business-critical checkout flow written in React and used by dozens of clients, including Wix, WooCommerce, Salesforce, and Big Commerce. Other highlights include the development of a greenfield React application to automate customer onboarding experience and maintenance of existing back office applications written in Angular.
Institutional Investors Analytics Platform
As a hands-on front-end technical lead, I successfully managed communication with key stakeholders, resolved cross-team dependencies with multiple back-end teams, and ensured that front-end team delivered critical features in a quality and timely manner.
The work involved a deep dive into the institutional investment domain and visualization of complex asset liability models.
Education
Bachelor of Science Degree (Hons.) in Computing and IT (Software)
The Open University - Remote, United Kingdom
Skills
Libraries/APIs
React.js, jQuery, Highcharts, JavaScript, Redux-Saga, Node.js, RxJS
Tools
Webpack, Flow, Sketch, Figma, GitHub, Lerna, Git, WebStorm, Jira
Languages
TypeScript, JavaScript, HTML, CSS, HTML5, GraphQL
Frameworks
Redux, Jest, Cypress, Next.js, Angular, Tailwind CSS, Material UI
Paradigms
Unit Testing, Testing, Agile Development, Agile Development, REST, Azure DevOps
Platforms
VWO, MacOS
Other
Apollo, Server-side Rendering (SSR), UI Development, UX Development, UI Development, Architecture, Front-end, Technical Architecture, Technical Leadership, Web UI, Web UX Design, Reusable Libraries, A/B Testing, Analytics Development, Mentorship, Leadership, GatsbyJS, Startup Development, Crypto
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