
Mikhail Koviazin
Verified Expert in Engineering
Web Developer
Shanghai, China
Toptal member since September 22, 2021
Mikhail is a senior full-stack engineer with 12+ years of experience specializing in web scraping and browser automation under anti-bot protection. He's built scraping systems covering 5+ million products across 1,000+ sites and shipped 50+ browser extensions for Chrome, Firefox, and Safari. Mikhail's recent focus is on AI agents and browser automation, including LLM extraction with deterministic validation, CAPTCHA solving without a headless browser, and systems achieving 99%+ reliability.
Portfolio
Experience
- Web Development - 12 years
- JavaScript - 11 years
- Web Scraping - 11 years
- React - 11 years
- Node.js - 11 years
- NoSQL - 10 years
- TypeScript - 10 years
- Chrome Extensions - 10 years
Preferred Environment
Git, WebStorm, Windows, Node.js, Playwright
The most amazing...
...work I've done is a browser-automation workflow that cut a property-management job from 8 minutes, often timing out, to 70 seconds at over 99% reliability.
Work Experience
AI Agent and Browser Automation Engineer (via Toptal)
Verifast, Inc
- Rebuilt an inherited RealPage SPA connector, replacing LLM-driven browser steps with deterministic DOM interactions and keeping the LLM as a fallback: runtime went from 7-8 minutes, past the 10-minute limit, to 60-75 seconds at 99%+ reliability.
- Revived a ResMan connector that had been switched off and left broken, with applications processed by hand: every step rebuilt as a deterministic DOM flow with an LLM fallback, and put into production for the first time.
- Built driver-license validation against official state DMV sources with no public API, shipping Florida over plain HTTP with CAPTCHA solving and no headless browser, on a design where adding a new state is a plug-in.
- Implemented I-20 and I-901 (SEVIS fee) form validation through imitated browser requests.
- Generalized the team's reusable workflow template out of two connectors: a step factory with optional browser context, field validation, and skip conditions, plus a DOM-first runner with LLM fallback, and wrote the guide documenting it.
Senior Chrome Extension Engineer (via Toptal)
Saleo Inc.
- Developed and maintained the browser extension for an AI-powered live demo platform that personalizes and controls demo data directly inside live third-party products.
- Implemented the Demo Sync feature that significantly decreased time costs for enterprise sales, presales, and enablement teams.
- Integrated the existing real-time data sync into personalized demo charts and tables, substituting API and WebSocket data so child demos override only the data they need.
- Delivered further full-stack features across the extension, portal, and back end: external start-demo URLs, personalized global CSS, URL matching enhancements, and portal performance fixes.
Senior Browser Extension Developer (via Toptal)
Numen Capital LLP
- Rewrote the extension prototype from MV2 to MV3 (to be able to publish the extension in the Chrome Web Store). Refactored state management system and text highlighting algorithms.
- Implemented PDF file interception in the extension (local and web-based documents) under MV3, with text highlighting in a custom PDF viewer (PDF.js).
- Rendered all on-page UI inside Shadow DOM so host-page styles cannot reach it, plus a keep-on-top routine that re-checks its own stacking against other extensions.
- Built new extension UI components and fixed issues in the existing prototype UI.
- Raised a privacy and performance problem the client had not asked about: the whole page HTML was leaving the browser on every user action.
Browser Extension Deployment Specialist (via Toptal)
Stage Front Tickets, Inc.
- Reviewed a ticket broker's internal pricing extension for Chrome Web Store eligibility and stripped every permission the code did not actually use.
- Wrote the Permission Justification, Single Purpose and Data Usage sections of the submission, which is where store reviews usually fail.
- Prepared the store submission and handed it back to the client, and registered and handed over their Chrome Web Store developer account.
- Advised on the policy questions behind it: privacy-policy updates after publication, and remote or dynamically evaluated code as a hard blocker.
Senior Browser Extension Developer (via Toptal)
Shady.Club Ltd
- Took a brand-ethics labeling extension forward from MVP, surfacing Good On You sustainability ratings on product cards across European fashion retail sites.
- Rebuilt the brand-matching system between product cards and the brand database, eliminating false positives and negatives for brands with overlapping names (deterministic, no AI).
- Improved the database architecture to match brand data faster.
- Reworked the on-page UI and pop-ups to run smoothly over heavy third-party SPA sites.
- Shipped in-product AI: similar-product search by image, where a click on any product picture returns higher-rated alternatives.
Senior Full-stack Developer (via Toptal)
Kenneth Corigliano
- Developed a full-stack real-estate product: a browser extension for sharing property notes across listing sites, plus the back end and an admin dashboard to manage users and notes.
- Detected listing pages on three major real-estate sites, parsed the address off the page and keyed notes to it, with a manual link-up when the addresses did not match.
- Implemented a user-friendly notes-sharing flow for users without an installed browser extension, which allows those users to install the extension and review the property notes.
Senior Full-stack Web Developer
Fatcoupon Technology
- Architected and developed a cross-browser extension for auto-applying coupon codes and cashback across 1,000+ online stores, reaching 30,000+ users at a 4.8/5 rating.
- Created a system for automated web scraping and price updating over 5,000,000 products and deals from over 1,000 websites.
- Automated routine business tasks such as scraping deals and coupons, registering accounts, and cleaning affiliate links.
- Led a team of three software engineers, mentoring and reviewing the code.
- Worked closely with the product owner and product manager on analyzing competitors, business needs, and development vectors from the technical side.
Senior Full-stack Web Developer (via Toptal)
WFHLAND Inc.
- Architected and developed a browser extension for making on-page web notes across websites and on online/local PDF files.
- Integrated an open-source web notes engine with a browser extension and improved its algorithms for better (de)serialization of web notes over various websites, including complicated cases with highly dynamic websites and online/local PDF files.
- Integrated an open-source library for rendering PDF files and improved some of its features. Developed web notes functionality for PDF files.
Senior Browser Extension Developer (via Toptal)
1Blocker LLC
- Adapted open-source ad-blocking scriptlets to Safari, where blocking runs through content blocker rules and page scriptlets rather than request interception, and wrote the desktop- and mobile-specific ones the open-source sets lacked.
- Extended and deeply refactored the existing ad-blocking web extension functionality for Safari on iOS and macOS.
- Developed a custom solution for data storage that works in a specific web extension environment.
- Reverse-engineered competitor ad-blocking extensions (open-source and proprietary) to inform architecture decisions, and produced a feature comparison for the client.
- Wrote targeted blocking logic for YouTube and Twitter to counter aggressive anti-ad-block measures, which change on the sites' side constantly.
Full-stack Web/Browser Extension Developer
Freelance Clients
- Developed and maintained over 50 browser extensions and web service projects.
- Used web scraping to extract data from websites, including Amazon, Google, Facebook, Instagram, Twitter, LinkedIn, and others.
- Built LinkedIn and Sales Navigator automation for lead generation and enrichment: exporting profile and connection data (name, email, company, title, location) to spreadsheets, and tagging company accounts from a source list.
- Created web automation across different sites: checkout automation, bulk messaging, and personalized outreach flows built from each profile's own data.
- Automated full authenticated user flows on heavily bot-protected platforms (login, navigation, search, posting, data collection), including IP rotation, proxy, and browser fingerprint management.
Software Developer
66Bit
- Developed a web service for aggregation and one-point management of four context ad networks and analytics services.
- Maintained and added new features for the English learning desktop application.
- Led a team of two developers, reviewing and mentoring them while working on English learning mobile and desktop apps.
- Helped develop a SaaS for obtaining access to wifi access points through social networks.
Experience
FatCoupon Browser Extension
https://fatcoupon.com/chrome-coupon-extension• Researched competitors and wrote the software requirement specifications.
• Planned the architecture of the project and chose the most appropriate technology stack.
• Architected a uniform JavaScript solution for auto-applying coupons on 1,000+ websites in multiple desktop browsers and mobile apps (Android, iOS) via WebView.
• Kept server-delivered store connectors working after Manifest V3 banned remotely delivered code: connectors are parsed into an AST and run by an interpreter inside the extension sandbox, a subsystem still present in the published build.
• Developed the extension's front end using React, Redux, and TypeScript.
• Integrated an auto-applying coupons function into mobile apps using Kotlin and Swift.
• Led a team of three developers while integrating 1,000+ websites with extensions.
Automated Product Scraping System
• Researched competitors and wrote the software requirement specifications.
• Planned the project architecture and chose the technology stack.
• Architected a uniform JavaScript solution for scraping 1,000+ websites, including those requiring browser rendering and scraping-protection bypass.
• Built the crawling layer on Apify SDK v1, the codebase that later became Crawlee, running it locally rather than on the hosted platform, with custom scraper base classes over its Cheerio and Puppeteer crawlers.
• Developed the dashboard front end using React, Redux, and TypeScript, and the back end using Node.js, Express, Passport, MongoDB, and TypeScript.
• Set up the CI/CD pipeline and ran the system on AWS EC2 under PM2, with the same team of three integrating new sites.
Facebook Dating Extension and Website
• Developed the front end for both the extension and the website using React and Bootstrap.
• Developed the back end using Node.js, Express, MongoDB, and Webpack.
• Built subscription billing as a separate service with its own payment-gateway integration, so subscriptions and in-app purchases were handled independently of the main application.
• Set up the CI/CD pipeline for deploying on Heroku.
Contextual Ad Network Management Service
• Wrote the technical specification, chose the stack, and built the first working prototype alone before the project got a repository and a team.
• Integrated and unified management functions of four different APIs: Google Ads, Google Analytics, Yandex Direct, and Yandex Metrica.
• Designed one domain model over both ad platforms with two-way synchronization, so changes made in the service propagated out into the ad networks and network-side state came back in.
• Designed bidding automation around the platform's rate limit (3,000 changes per campaign per day, so 125 keywords on an hourly cycle), with full caching required to stay inside the quota.
• Built the server-rendered UI for most of the product screens (ASP.NET MVC Razor, Bootstrap, jQuery), including ad editing and the on-site form and click collector; a dedicated front-end developer carried the layout and most client-side JavaScript.
• Built the back end using ASP.NET MVC, EF6, MS SQL Server, and Windows IIS Server; the service ran in production for a year against a real advertiser's live campaigns.
Used-book Arbitrage Monitoring System
• Built the whole pipeline on plain HTTP with axios and Cheerio, no browser anywhere, so a sweep costs milliseconds and fits inside the client's proxy budget of 1,000,000 requests per month.
• Rewrote the system in TypeScript and moved it into Docker on the client's AWS EC2, with per-second ticks and a schedule that polls faster during peak buying hours.
• Replaced HTML scraping of a 50-million-record catalog with batched queries against the site's own search index: 15,000 watched ISBNs are now covered by three requests per pass.
• Made silent failure visible: a sweep that parses zero listings raises a warning instead of looking like a quiet market, which is how a markup change had gone unnoticed for days.
Marketplace Product Research System
• Built a Chrome extension (Manifest V2) that extracted listing data from Amazon and eBay into the spreadsheet, plus an Excel VBA layer that fitted product photos into cells by ASIN and generated per-row link buttons.
• Replaced a paid tool's estimated monthly sales with real per-date transaction counts parsed from eBay's Purchase History, with captcha detection and request throttling built in from the start.
• Caught the paid estimator returning wrong numbers for a whole category two weeks in, reported it in writing rather than shipping the figures, and switched the company onto another tool the same day.
• Ran the marketplace and payment accounts behind the research, and rewrote supplier copy into sellable listings. At least one study went from research to a sourcing decision and factory samples.
Education
Master's Degree in Software Engineering
Harbin Institute of Technology - Harbin, China
Bachelor's Degree in Applied Informatics
Ural State University of Economics - Yekaterinburg, Russia
Skills
Libraries/APIs
Node.js, React, Puppeteer, CheerioJS, REST APIs, API Development, Playwright, Claude API, iOS Extensions, Stripe, Stripe API, OpenAI API, Google API, Entity Framework, Windows Forms (WinForms), PhantomJS, Google Analytics API, Google Ads API
Tools
WebStorm, Webpack, Claude Code, Claude, Git, GitHub, Front-end Build Tools, ChatGPT, Microsoft Excel, Google Sheets, WebView, SourceTree, Slack, Figma, Zapier, Prisma, n8n
Languages
JavaScript, TypeScript, HTML, CSS, C#, SQL, Excel VBA, PHP, Kotlin, Swift, Python
Frameworks
Express.js, Chrome, Redux, Bootstrap, .NET, Jest, Next.js, Agentic Frameworks, ASP.NET MVC, Windows Presentation Foundation (WPF), Material UI, Scrapy, Selenium
Paradigms
ETL, HTML DOM, Automation, Testing, REST, Unit Testing, Model Context Protocol (MCP)
Platforms
MacOS, Google Chrome, Amazon EC2, Amazon Web Services (AWS), AWS Lambda, Vercel, Docker, Heroku, Windows Server, Windows, PDF.js, Azure
Storage
Data Pipelines, JSON, MongoDB, Amazon S3 (AWS S3), Databases, PostgreSQL, NoSQL, Database Architecture, MySQL, Redis
Other
Web Scraping, Chrome Extensions, Software Development, Web App Automation, Apify SDK, Web Development, Web Extensions, APIs, Software Engineering, Firefox Extensions, Web Crawlers, Large-scale Web Crawlers, Scraping, Data Scraping, Robotic Process Automation (RPA), Browser Plugins, Full-stack, Browser Automation, Manifest V3, Front-end, Front-end Development, MV3, MV2, Workflow Automation & System Integration, MacBook, AI Agents, Large Language Models (LLMs), OpenAI, Full-stack Development, API Integration, Artificial Intelligence (AI), Technical Architecture, Data Engineering, Code Auditing, Anthropic, Workflow Automation, Business Process Automation, Software Architecture, AI-assisted Development, LLM Integration, Data Extraction, Workflows, Integration, ETL Pipelines, Architecture, Website Data Scraping, Data Transformation, Proxies, System Architecture, Systems Design, Scripting, Automations, AI Automation, Payment Gateways, Facebook, Safari Extensions, Axios, Algorithms, Application State Management, AI Tools, Agentic AI, AI Agent Orchestration, AI Integration, AI Development, Vibe Coding, User Interface (UI), Authentication, Document Processing, Data Analysis, Data Mining, LinkedIn, Payment APIs, SaaS, Cloud Infrastructure, Lead Generation, LinkedIn Sales Navigator, Agentic Coding, ETL Tools, System Design, Solution Architecture, Data Reporting, API Management, Prompt Engineering, OpenAI GPT-4 API, Communication, Minimum Viable Product (MVP), MVP Design, Technical Leadership, Agentic Workflow Design, Leadership, Payments, CSV, Storybook, CI/CD Pipelines, Spintax Generator, Yandex.Direct, Yandex.Metrika, ESLint, Lint, HTML Canvas, CAPTCHA, WebSockets, Supabase, Mastra, Browserbase, Stagehand, Inngest, Gemini, Supply Chain, Supply Chain Operations
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