# Boris Petrov > Senior Frontend Engineer | ex-Google, Amazon | Fractional Location: San Francisco Bay Area, United States Profile: https://flows.cv/boris I’m a senior frontend engineer with over a decade building products at Google, Amazon, and startups. I now work independently, part-time, with startups that need high-leverage frontend execution without adding another full-time hire. Teams usually bring me in at inflection points: early product iteration when scope is still moving, pre-launch crunch, growth spikes, fundraising pressure, or a codebase that got shipped fast and now needs stronger structure. Most of my work is in React/TypeScript apps with heavy client-side state, complex async behavior, and product surfaces where design and backend constraints collide. Recently, that’s often included AI-assisted workflows where the real challenge is making messy system behavior feel clear and reliable to users. I embed directly with product, design, and engineering as a hands-on senior IC. Typical engagements are 10-30 hours/week, lasting a few weeks to about a year. I focus on shipping what matters now while leaving the frontend in a state your team can build on confidently after I roll off. ## Work Experience ### Freelance Software Engineer @ borispetrov.dev Jan 2021 – Present | San Francisco, California, United States Building web app user interfaces and API integrations for a variety of clients. ### Frontend Engineer @ Navii Jan 2025 – Jan 2025 | San Francisco, California, United States Brought on in the month leading up to a major launch to stabilize the React/TypeScript frontend of an AI-driven career development product that had scaled rapidly through agent-assisted development. Surfaced architectural issues around state management, component lifecycle, and caching. Recommended and implemented the highest-impact fixes that could be responsibly completed before launch. Laid groundwork and guardrails for more fundamental changes to be tackled post-launch. ### Frontend Engineer @ Radical Tempo Jan 2024 – Jan 2025 | San Francisco Built an AI-augmented web app for video content publishers (second engineer hired; went from zero to an early-access launch, with dozens of design partners and thousands of free-tier signups). Responsibilities included: - working closely with the design team to craft cutting-edge user experiences for soliciting content suggestions from an AI assistant, evaluating those suggestions, and merging them into existing human-generated content - building publishing workflows that allow users to upload once and publish to all major video platforms with just a few clicks - orchestrating the progress of multi-phase backend processes (video transcoding, publishing, AI clip and thumbnail generation) and notifying users of outcomes - using the latest from React and NextJS – coupled with Supabase Realtime – to build a snappy, live-updating UI that allows multi-user collaboration on a shared workspace ### Frontend Engineer @ Play SF Jan 2023 – Jan 2025 Responsible for upkeep of Play's own website (https://play.studio) and occasionally contributing in a frontend engineering capacity to Play's external client projects. ### Lead Software Engineer @ Planetary Jan 2023 – Jan 2024 Led a team of 3 engineers assigned to agency client California Pizza Kitchen's website and ordering system, across client (React, Flow Type), CMS (Sanity), and backend (Azure, Docker, Kubernetes); reduced home page load time by 25%; created smart URL redirect system to route users from the CPK-owned site to a third-party ordering platform (Olo), including persisting loyalty program login session between cpk.com and the ordering platform; reduced CMS (Sanity CMS) cost by pruning unnecessary datasets and optimizing size of images loaded on site; led effort to make site compliant with WCAG accessibility guidelines; introduced CMS-customizable, mobile-responsive menu page; audited the website for compliance with rules of the Olo API, including caching data to reduce number of API requests; improved location finder to enable users to search by various geo entities (like city, state, zip) rather than just "nearby"; created Olo API-powered, SEO-optimized page for each CPK restaurant location; revived abandoned/broken Flow-type type checking system to improve confidence when shipping new features on the client ### Software Engineer @ Stealth Startup (AI for Youth Sports Coaching) Jan 2023 – Jan 2024 Helped a pre-seed startup by: - building their "Playground" website, on which prospective users can play with a demo of the functionality available in the startup's iOS app - contributing to their React Native -powered iOS app ### Frontend Web Developer @ TWL Jan 2024 – Jan 2024 ### Consulting Software Engineer @ SpeakEasy Political Jan 2022 – Jan 2023 - Improved code stability and hygiene by introducing TypeScript, Prettier, ESLint, and CSS Modules to the codebase - Reduced errors in communication between React client and Rails backend by centralizing serialization/deserialization code and validating API responses ### Frontend Engineer @ Lasso Labs Jan 2022 – Jan 2023 - Built analytics dashboard for NFT collections (Highcharts.js) - Implemented "live search" component in nav - Gated closed-beta content behind auth based on NextAuth + Wagmi (i.e. wallet connect) - Worked on internal tool that uses a multi-step form (wizard) to merge content from Twitter API and GPT3 with user input (React, Tailwind, Material UI) ### Frontend Engineer @ Mirror Jan 2022 – Jan 2022 Implemented redesign / rebranding of their React + Next.js powered responsive landing page ### Full Stack Engineer @ Subcity Jan 2022 – Jan 2022 Full-stack work on a web app positioned as the "TurboTax for government tax incentives" (React, Rails, Postgres). - Made HTML forms more robust and easy to use (e.g. autosave, client-side validation, Google Maps address autocompletion) - Introduced system for generalizing from a single type of government incentive form to multiple, by augmenting their DB schema, extracting common client code into reusable modules, and defining forms in JSON Schema ### Software Engineering Consultant @ Databanc Jan 2022 – Jan 2022 Hired by non-technical solo-founder at the beginning stages of building a privacy-focused data storage app to vet technical feasibility of proposed features and write a tech spec / design document. ### Software Engineer @ YouTube Jan 2016 – Jan 2019 | San Bruno Worked primarily on YouTube Studio (f.k.a. "Creator Studio"), which is where creators manage their content and identity (images, bio) on YouTube. On the client side, I wrote JavaScript and TypeScript within a Redux + Polymer framework; my server side work was mostly on Python servlets. All code pushed adhered to Google's high standard of test coverage, accessibility, and UI homogeneity. In addition to coding, I authored multiple design docs and rallied consensus for projects between teams in a variety of product/infrastructure areas across YouTube and Google. Finally, to support the products I launched, I integrated with Google's distributed logging, monitoring, and experiment systems. I responded to high-priority alerts as part of an on-call rotation and measured the performance of features that were launched behind experiment flags. ### Software Engineer (Frontend) @ BandPage Jan 2015 – Jan 2016 | San Francisco, California • Using Facebook's ReactJS framework and Flux architecture on the client and Node/Express on the server, I built an internal tool that our Content Team uses to review and edit the ticket purchase URLs for concerts ingested from upstream partners. To handle concurrent use by multiple team members, the tool includes a multi-server Memcached-based locking mechanism that prevents more than one person from editing a given event's ticket URLs at a time, as well as client-side user activity tracking that continuously extends the TTL of the lock for the currently edited event • Led the development of a tool that would allow the Artist Relations team to customize the content (text, images) and fan target segments of push notifications that we send via Rhapsody. This task included putting together the tech spec for the project (which in turn meant planning out new APIs), as well as setting (and meeting) milestones, delegating sub-tasks to the other engineers involved, and providing a test plan • Early on in BandPage's partnership with Rhapsody, I developed a template of a responsive web page that would be sent to customers (as a push notification) and would thereby be viewed on devices ranging from large tablets to small, low-resolution smartphones • Made usability improvements to the BandPage profile editor, whose client is written in a modified version of Backbone and whose server runs on Node ### Software Development Engineer @ Amazon Music Jan 2013 – Jan 2015 | San Francisco • Migrated the server-side code of the digital music desktop web “detail pages” (e.g. tinyurl.com/mrdqcg2) from Perl/Mason to Java/JSP and Amazon’s internal Spring-MVC-powered “DPX” framework • Revamped the appearance of those same digital music detail pages using the AmazonUI front-end framework (which involves writing SCSS and modular JS) • Updated our 30-second-sample player JS to use HTML Audio when possible and seamlessly fall back to Flash Player for older browsers; also added an elegant progress bar and countdown animation to the sample buttons using CSS and JS • Coordinated the format of Prime-signup-URL ref markers across multiple teams and platforms/devices during the launch of Prime Music and in doing so, aided our metrics team in determining what Digital Music features and ad campaigns that were most effective in driving new Prime memberships • Working closely with our marketing team, I created a promotional page for Prime Music that is responsive to virtually any screen size and orientation (tinyurl.com/amzpulp) • Helped to devise my team’s Git branching and prod deployment approach • Led my team’s Java unit testing efforts by establishing style guidelines and integrating the PowerMock and EasyMock frameworks into our existing unit tests ### Software Engineering Intern @ Google Jan 2012 – Jan 2012 | Mountain View • Added feature to Google Analytics that enables users to create and view a custom group of metrics across all existing reports. • Modified the Analytics front-end framework as needed and added Java/JS unit tests for all changes. • Proposed a trajectory of future development for my new feature in a design document. ### Software Engineering Intern @ Plaxo Inc Jan 2011 – Jan 2011 | Sunnyvale • Created a dynamic “dashboard” web page to display internal product statistics • Built prototype web app for a TV guide centered on what your friends are watching • Wrote a PHP script that gathers new TV schedule data nightly from external sources and merges it into the existing internal MySQL tables, automatically reconciling conflicts when possible and alerting administrators by email of conflicts requiring human intervention • Optimized MySQL queries and modified the existing database schema to accommodate my additions ## Education ### Bachelor of Arts - BA in Computer Science University of California, Berkeley Jan 2009 – Jan 2013 ## Contact & Social - LinkedIn: https://linkedin.com/in/borislavppetrov --- Source: https://flows.cv/boris JSON Resume: https://flows.cv/boris/resume.json Last updated: 2026-03-22