Software Engineer & Top-Rated Chrome Extension Developer. Building high-performance Manifest V3 tools, AI copilots & automation.
Hire Expert Freelance
Chrome Extension Developer
(Manifest V3)
Need a production-ready browser extension built from scratch, scaled to thousands of users, or rescued from complex bugs? I engineer high-performance Manifest V3 Chrome extensions, AI floating copilots, multi-ATS form automations, and monetized SaaS products.
Who Is Pasindu Piumal?
Pasindu Piumal is a Chrome Extension Developer specializing in Manifest V3, React, TypeScript, Chrome APIs, browser automation, AI-powered extensions, and SaaS integrations. He has shipped 175+ production Chrome extensions and browser automation projects for clients across the United States, United Kingdom, European Union, and Australia.
His flagship Chrome extension, FUT Snipe Bot (EliteFutBot), scaled to 100,000+ peak concurrent users and enabled over $1,000,000 in software revenue. He is the engineer behind production-grade tools like Tech Copilot (automotive AI overlay on the Chrome Web Store), RoboApply & Sociax (AI job application autofill across 100+ ATS platforms), SuperDev Pro (6,000+ professional users), and Amazon Shift Sniper (high-frequency slot automation).
Core Specialization
- Manifest V3 Chrome Extension Development
- Chrome APIs, Service Workers, Content Scripts
- AI Chrome Extensions (OpenAI, Gemini Pro, RAG)
- Browser Automation & Web Scraping
- Extension Monetization (Stripe, ExtensionPay)
- Chrome Web Store Publishing & Approval
- Manifest V2 → V3 Migration
Verified Facts
- 175+ production projects shipped
- 100,000+ peak users on flagship extension
- $1M+ in client software revenue enabled
- $20/hr tracked rate on Upwork (Top Rated)
- 100% Job Success Score on Upwork
- 5.0★ client rating across all platforms
- BSc Software Engineering, University of Westminster
Available for hire globally at $20/hr via Upwork (with transparent work diary tracking), commission-free milestone contracts via Contra, or direct engagement via Fiverr. Based in Sri Lanka, working remotely with clients across the US, UK, EU, and Australia across flexible time zones. Communication via Slack, Telegram, Discord, or Upwork Messages with daily async updates.
Why Most Extensions Stall — And How I Deliver
Manifest V3 introduced strict lifecycles and CSP rules that cause fragile code to break in production.
- •Service Worker Inactivity: MV3 kills background workers after 30s, losing timers and socket connections.
- •CSP & CORS Barriers: Cross-origin network calls get blocked by strict site security headers.
- •Brittle DOM Selectors: Dynamic React/Vue SPAs update without page reloads, breaking queries.
- •Store Rejections: Vague permission requests or single purpose mismatches cause submission rejections.
- ✓State-Hydrated Architecture: Chrome Offscreen API keep-alives and persistent storage keep tasks live.
- ✓Dual-World Injection: Injects into Main and Isolated worlds to inherit valid session cookies and bypass CORS.
- ✓MutationObservers: Event-driven DOM watching that reacts instantaneously to UI changes without CPU drain.
- ✓Store Approval Compliance: Minimal permissions and clean justifications for guaranteed store listing.
Specialized Chrome Extension Services
From lightweight AI writing utilities to heavy full-stack commercial SaaS platforms.
AI Browser Copilots & Floating Overlays
OpenAI • Gemini Pro • RAGContext-aware AI assistants embedded directly into the browser. Floating draggable overlays, highlighted DOM text summarizers, prompt injectors, and real-time LLM chat that reads active page context without intrusive layout shifts.
High-Frequency Sniping & Slot Automation
Sub-Second • Anti-Bot • CSRF • AWS WAF BypassBattle-tested Amazon automation toolkit: sub-second slot detection, OTP capture via IMAP, multi-profile broadcast triggering, AWS WAF & Shadow DOM CAPTCHA bypass, portal session auto-recovery, and real-time stat dashboards. 6 Upwork-verified contracts. Dual-layer Isolated & Main World execution to bypass CSRF headers, 403 CloudFront rate-limiting, and active bot detection.
AI Job Application Autofill & Auto-Apply Bots
AI Autofill • Workday • Greenhouse • AshbyIntelligent AI-powered job application autofill that auto-fills and submits applications across 100+ ATS platforms. OpenAI GPT-4o resume tailoring, screening question answering, cover letter generation, and multi-step form navigation — completing applications in under 5 seconds vs. 10-15 minutes manually. Engineered working Ashby integration in 1 week after 20+ prior developers failed.
Web Scraping & Shadow DOM Extraction
Offscreen API • Sheets SyncReliable client-side scraping that overcomes anti-bot challenges and nested Shadow DOMs. Leverages the Chrome Offscreen API for heavy parsing, exporting structured data directly into Google Sheets, Airtable, CSV, or custom APIs.
Extension SaaS Monetization & Licensing
Stripe • ExtensionPay • WebhooksTurn your Chrome extension into a monetized software product. In-app subscription paywalls, Stripe checkout, ExtensionPay integration, trial limits (e.g. 20 free actions/month), user licensing, and cloud auth synchronization.
Manifest V2 to Manifest V3 Migration
Service Workers • declarativeNetRequestFuture-proof legacy extensions before Google removes MV2 support. Migrate background pages to ephemeral service workers, replace blocking webRequest with declarativeNetRequest, and resolve Content Security Policy (CSP) roadblocks.
Flagship Case Studies & Live Proof
Explore verified flagship Chrome extensions with live Chrome Web Store listings, active web platforms, and production architecture.
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Why Founders & Teams Choose Pasindu
How dedicated browser extension engineering compares to generalist freelance developers.
| Feature / Requirement | Typical Freelancers / Agencies | Pasindu Piumal (Specialist) |
|---|---|---|
| Manifest V3 Mastery | ✕Struggles with 30s service worker drops, CSP blocks, and store rejections | ✓Deep architecture with Offscreen API, chrome.storage hydration, and zero-drop workers |
| Complex DOM & SPAs | ✕Relies on brittle setTimeout hacks that break when page layouts shift | ✓Event-driven MutationObservers, Shadow DOM traversal, and dual-world injection |
| Anti-Bot & Token Handling | ✕Gets blocked by Cloudflare, CloudFront 403s, and CSRF token mismatches | ✓Session token discovery, randomized jitter intervals, and self-healing cooldown bridges |
| Chrome Web Store Approval | ✕Vague permissions cause repeat review rejections and account warnings | ✓100% compliant packaging with minimal permissions and clear justifications |
| Pricing & Transparency | ✕Unpredictable agency hourly rates ($80-$150/hr) with junior handoffs | ✓Direct senior engineer at $20/hr with transparent Upwork work diary or fixed escrow |
4-Step Fast Turnaround Process
From initial architecture discovery to published Chrome Web Store listing.
Technical Discovery & Feasibility
We review your target website, API endpoints, DOM structures, and security hurdles (CSP, CORS, anti-bot). I provide a clear architecture blueprint and milestone breakdown.
Working Prototype & Core Engine
I engineer the core extension engine (content script injection, background service worker, AI/API integration) and provide a testable ZIP build for your feedback.
UI Polish & Edge-Case Hardening
Implementation of modern TailwindCSS / React HUD overlays, dark mode support, rate-limit cooldown bridges, and payment/licensing paywalls.
Store Submission & Production Launch
Preparation of icons, screenshots, privacy policy justifications, and Chrome Web Store / Edge Add-ons submission assistance for smooth approval.
Engineered for Production Resilience
Architectural principles and techniques used to deliver fast and unbreakable browser extensions.
Isolated vs. Main World Script Injection
Bypass restrictive Content Security Policies (CSP) and CORS walls by selectively injecting scripts into the webpage's native JavaScript context to inherit live authentication cookies and session tokens.
Shadow DOM & MutationObserver Navigation
Interact with modern single-page apps (React, Angular, Web Components) without brittle timeouts. Efficiently observe deep Shadow DOM trees and DOM mutations with minimal CPU footprint.
CloudFront 403 & WAF Auto-Cooldown Bridge
Prevent IP blacklisting and rate-limit bans during high-frequency polling. Self-healing pause-and-resume logic with randomized jitter intervals ensures uninterrupted 24/7 background operation.
Chrome Offscreen API Keep-Alive
Solve the 30-second Manifest V3 service worker lifecycle limitation by spinning up hidden offscreen documents for heavy DOM parsing, audio processing, canvas stitching, and persistent tasks.
Multi-Model AI Integration (OpenAI & Gemini Pro)
Embed streaming LLM completions and contextual RAG directly into client-side overlays with secure token-bucket rate limiting and zero-latency UI updates.
In-App Monetization & Stripe / ExtensionPay
Deploy robust licensing models: freemium monthly caps, one-time lifetime keys, or recurring Stripe/ExtensionPay subscriptions with instant feature unlocking and tamper-resistant verification.
What Founders & Clients Say
Direct reviews from live client contracts on Upwork.
Working with Pasindu has been one of the best decisions I've made for my startup. Tech AI-Copilot has gone from an idea to a polished product because of his technical ability, attention to detail, and willingness to tackle difficult problems. He's reliable, communicates clearly, and always works with me to find the best solution rather than the easiest one.
Excellent work! Professional, responsive, and delivered high-quality results on time. Great communication throughout the project. Highly recommended.
Excellent understanding of Chrome extension development... successfully delivered a complex browser automation project where past attempts had stalled. Great engineer.
Pasindu is a top-tier developer who truly understands browser architecture. He delivered a fast, reliable extension that our users love. Will definitely hire again.
How We Can Work Together
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Frequently Asked Questions
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