Frontend Developer with professional experience building polished, user-centered digital products in Marketing and Banking industries for Fortune 500 companies. Enjoys working close to design, collaborating cross-functionally, and bridging the entire software development lifecycle. Known for delivering accessible, testable frontends and design-system-driven UI, migrating legacy components, and building modular workflows and dashboards used by thousands of daily users.

William Greer

Frontend Developer with professional experience building polished, user-centered digital products in Marketing and Banking industries for Fortune 500 companies. Enjoys working close to design, collaborating cross-functionally, and bridging the entire software development lifecycle. Known for delivering accessible, testable frontends and design-system-driven UI, migrating legacy components, and building modular workflows and dashboards used by thousands of daily users.

Available to hire

Frontend Developer with professional experience building polished, user-centered digital products in Marketing and Banking industries for Fortune 500 companies. Enjoys working close to design, collaborating cross-functionally, and bridging the entire software development lifecycle.

Known for delivering accessible, testable frontends and design-system-driven UI, migrating legacy components, and building modular workflows and dashboards used by thousands of daily users.

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Experience Level

Expert
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Intermediate
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Language

English
Fluent

Work Experience

AI Model Trainer & Testing - UI Engineer at DataAnnotation
May 1, 2026 - Present
Evaluated AI model responses head-to-head (A/B), authoring detailed rationale on output quality, correctness, and instruction adherence. Benchmarked competing LLMs against real-world codebases and prompts, assessing task success and instruction-following on coding tasks. Authored complex, multi-turn agentic coding tasks (~5 turns), calibrating difficulty so target models fail at least 2 of 5 attempts on task success and instruction following.
Frontend Software Engineer at American Express
July 1, 2025 - November 1, 2025
Led modernization of the Business Checking Accounts onboarding flow by migrating legacy Angular applications to TypeScript and React, improving scalability and maintainability. Drove cross-team code and design reviews to establish React and TypeScript best practices across teams. Migrated 40 Angular-based Formik components to React Hook Form, improving data validation and load time. Implemented Zustand and Redux for scalable state management, and Yup and Zod for schema-based input validation across high-volume form systems. Maintained and optimized the enterprise micro-frontend architecture, enforcing modular design and clean deployments. Achieved 100% unit test coverage with Jest and React Testing Library. Partnered with design and platform teams to align with enterprise design systems and WCAG accessibility standards.
Frontend Software Engineer at Wells Fargo
June 1, 2024 - March 31, 2025
Built WCAG-compliant disclosures agreement workflows for the WF Cross-Channel Banking Platform using Module Federation. Led efforts to increase unit test coverage minimum from 65% to 90% to ensure platform reliability. Participated in extensive code review sessions to ensure adherence to company standards and improve outdated patterns.
Frontend Engineer II at Wells Fargo
June 1, 2024 - March 1, 2025
Delivered modular, pixel-perfect React.js components within a module-federated architecture as a proof-of-concept for enterprise-wide micro-frontends. Built an accessibility-first document attestation tool for in-branch users unable to sign, addressing WCAG and physical accessibility standards. Applied Redux and Redux-Saga to manage complex asynchronous data flows, ensuring reliable synchronization with Java-based Spring Boot API backends.
Marketing Web Applications Developer at Yahoo
February 1, 2022 - February 28, 2024
Worked cross-functionally in the Marketing group to support content-focused websites with thousands of daily visitors. Developed statically generated websites advertising core Yahoo B2B and B2C products using Next.js and React. Created custom Drupal CMS modules enabling self-service editorial workflows for content teams. Built a lightweight animation library for reusable company micro-interactions. Implemented internationalization (i18n) for globally distributed sites with automatic translation in CI/CD pipelines.
Frontend Applications Developer at Yahoo
February 1, 2022 - February 29, 2024
Supported content-focused websites in the Marketing group with thousands of daily visitors. Developed and maintained statically generated websites marketing Yahoo B2B Adtech products with Next.js. Built custom Drupal CMS modules to enable self-service editorial workflows for content teams, expediting publishing. Created a lightweight internal library to enable polished animations across statically generated sites. Implemented internationalization (i18n) for globally distributed websites with automatic translation in CI/CD pipelines.
Frontend Apps Developer at Yahoo! Inc.
February 1, 2022 - March 1, 2024
Developed SSR features powering content-rich consumer apps using Next.js. Created modular UI systems with React component patterns and CSS Modules. Built a custom internal SSR-ready animation framework to enhance UX performance. Upgraded vulnerable dependencies to safeguard platform integrity. Enabled internationalization (i18n) to support multi-locale products with automated en-US translations. Implemented a headless Drupal CMS to enable flexible content modeling and editor workflows for editors and copywriters.
Web Developer at Theia Interactive
January 1, 2021 - February 28, 2022
Developed and designed web-based 360° virtual walkthrough experiences for multiple high-value clients including Pampered Chef, Invisalign, and Grainger Industrial Supply using HTML, CSS, and JavaScript.
Software Engineer Freelance / Independent at Freelance / Independent
May 1, 2020 - Present
Engineered scalable full-stack applications by translating complex business requirements into maintainable solutions. Delivered custom 3D virtual environments for Pampered Chef and Invisalign. Clearly communicates UX decisions, constraints, and trade-offs to project managers and stakeholders; owns end-to-end design and development workflows while collaborating directly with high-profile clients.
Freelance / Independent Software Engineer at Freelance / Independent
May 1, 2020 - Present
Engineered scalable, intuitive full-stack applications by translating complex business requirements into maintainable technical solutions. Delivered custom 3D virtual environments for Pampered Chef and Invisalign. Clearly communicates complex UX decisions, constraints, and trade-offs to project managers and stakeholders. Owned end-to-end design and development workflows while collaborating directly with high-profile, often non-technical clients.
Founder / Sole Designer & Developer at Senet Estate Sales
January 1, 2020 - Present
Owned the product end-to-end remotely: content strategy, information architecture, and visual design in Figma. Designed interactions and animation using Framer Motion, and implemented the full build using Next.js, TypeScript, Sanity, and MongoDB. Made independent tech-stack and UX tradeoff decisions balancing performance, SEO, and long-term maintainability. Achieved first-page search rankings and increased client revenue by 100%+ post-launch while sustaining Lighthouse scores above 90.

Education

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Qualifications

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Industry Experience

Software & Internet, Financial Services, Media & Entertainment, Professional Services, Computers & Electronics
    Furrow Studio

    Furrow is the site of a full-service creative studio focused on video production — pitched around the tagline “DIG DEEP,” the idea that great stories have to be uncovered, “dirt under our fingernails and all.”

    The design is bold and cinematic: a black background with huge white display type, a single red-dot accent, and scroll-driven animations. Content-wise it’s a one-pager covering a featured project (PEI Seafood), a studio blurb (“Furrow is an integrated, full-service creative studio offering video production, creative development, and post-production services”), and a detailed services list spanning pre-production (creative development, writing, storyboards, art/creative direction, location scouting, casting), production (principal photography, production management, crew, dailies, LTO archiving), post-production (color correction, editing, VFX, motion graphics, captioning), and partner-provided audio post (sound design, SFX, music, mix).

    Compared with the Ollie site, it’s the same genre — an animation-heavy agency portfolio page — but with a grittier, film-production personality rather than Ollie’s clean minimalist branding angle.

    Ollie Branding Studio

    Ollie is a demo website for a fictional brand experience studio. It’s a polished, animation-heavy single-page React site with a minimalist black-on-light-gray aesthetic: it opens with a slow-fading photo collage of bright, modern studio interiors, followed by oversized scrolling “ollie” wordmark typography and scroll-driven transitions throughout.

    The content pitches Ollie as a small agency “specialised in setting up the foundation of your brand.” It’s organized around four offerings: Design (identity, art direction, product), Strategy (positioning, narrative, naming), Studio (two founders, one point of contact), and Why us (systems your team can run) — summed up by the line “One studio, four disciplines,” with everything feeding one reusable brand foundation. It closes with a “Let’s work together” call to action.

    Overall, it reads as a portfolio/landing-page demo showing off modern web animation and editorial design rather than a functioning agency site.