All projects Chrome Extension · Prototype

WhatsApp
Smart

2.5 billion people use WhatsApp every day. Zero productivity tools. Gmail got smart replies in 2017. WhatsApp added basic single-message scheduling in February 2026, buried in the UI. Still no AI, no way to catch up on a hundred group messages, no follow-up reminders. Nobody's building for the people who just use WhatsApp to talk to friends, family, and colleagues. So I started building it.

16k+ Lines of code
50+ React components
7 Core features
130+ Source files
Scroll
Chrome Extension /TypeScript /React /Privacy-First /AI Replies /Scheduling /WhatsApp /16.5k Lines /Chrome Extension /TypeScript /React /Privacy-First /AI Replies /Scheduling /WhatsApp /16.5k Lines /
WhatsApp Web
🔒 web.whatsapp.com

Chrome extension showing AI suggestions, tone control, and scheduling Prototype

01 / The Problem

The missing layer

I kept running into the same friction. Want to schedule a birthday message for midnight? Can't. Need to catch up on a family group chat with 120 unread messages? Scroll through every single one. Want quick reply suggestions when you're juggling ten conversations? Nothing.

The gap is bigger than scheduling. There's no personal productivity layer at all. WhatsApp's own scheduling, added in early 2026, is single-message only with no recurring option. Every third-party tool in this space targets businesses running customer support through the WhatsApp Business API. Personal users got left behind. That's the gap I'm filling.

02 / How It Works

Three-layer architecture

You open WhatsApp Web and the extension is already there. A small toolbar next to the compose box. Type a message and you'll see AI suggestions, a tone adjuster, and a schedule button. Behind it, everything runs locally in the browser.

A content script injects the UI via shadow DOM so it never clashes with WhatsApp's own styles. A background service worker handles scheduling through Chrome Alarms, so messages go out even if the tab isn't focused. Message access comes from the WPP library (an open-source WhatsApp Web API), not brittle DOM scraping. No server required for core features. No sign-up.

Browser Layer
Entry point
Content Script
Injects into WhatsApp Web DOM via MutationObserver detection
Main world
Injected Script
WPP bridge for programmatic message access
Shadow DOM
Isolated React mount. Never clashes with WhatsApp CSS
Message Bridge
postMessage relay between content + injected scripts
React 19 UI
54 components: Radix primitives, Tailwind v4, shadcn/ui
Extension Layer
Service worker
Background Worker
1,400 lines: scheduling engine, send queue, orphan recovery, tab manager
Chrome Storage
All user data local. Scheduled messages, voice profiles, office hours, reminders
Chrome Alarms
OS-level timing. Fires even when tab unfocused or worker asleep
Send Queue
Retry logic, staggered batch delivery (3-10s gaps), status tracking
Tab Manager
Auto-opens WhatsApp tab for scheduled sends, closes when done
External Services (optional)
BYOK / proxy
Claude API
Haiku 4.5 for speed, Sonnet 4.6 for quality. Direct from browser or via free-tier proxy
Hono Server
Push notifications when Chrome closed. AI proxy with 10 free actions/month
Upstash Redis
Server-side schedule state, push subscriptions, usage metering
03 / Features

What it does

01

Smart Scheduling

Schedule one-off or recurring messages. Enforces per-contact office hours so messages don't fire at 3am. Supports intelligent batch sending with staggered delays.

02

AI Reply Suggestions

Reads the context of the chat and suggests 3 replies instantly via Claude Haiku. Learns your personal emoji habits and tone.

03

Tone Adjuster

Draft quickly, then click to rewrite as formal, casual, or professional. Seamless context switching.

04

Group Chat Summary

Instantly summarise 30+ unread messages. Extracts decisions, assignees, and deadlines into structured bullets.

05

Undo Send

Intercepts messages with a 5-second countdown bar. Cancel anytime before it hits WhatsApp's servers.

06

Follow-Up Reminders

Flag messages to bounce back to your attention later. Set keyword alerts for terms like "urgent" or "deadline".

07

Privacy-First

All data stays in local Chrome storage. No sign-ups required. Bring your own API key or use the free tier proxy.

04 / Tech Stack

What it's built with

React 19
UI + state
TypeScript 5.9
Type-safe code
WXT
Extension framework
Tailwind v4
Utility styling
Radix UI
Accessible primitives
Claude API
Haiku + Sonnet
Chrome Alarms
Background scheduling
WPP / wa-js
WhatsApp DOM access
Hono
Push + AI proxy
Next.js 15
Landing page
Vite
Build tooling
Upstash Redis
Server state

Every WhatsApp extension I found was built for businesses. I just wanted to schedule a birthday message.

Other Projects
OpsPilot dashboard
Production

OpsPilot

Enterprise version of the same AI-first thinking. 60k lines of Python, production infrastructure, Xero + HubSpot integration.

View case study
Trading Bot backtest
Paper Trading

Trading Bot

Multi-agent Python system with the same structured-output approach. Four agents, deterministic risk management.

View case study
Uni-Nation website
Live

Uni-Nation Digital

Full-stack Next.js site for the family textile business. Different domain, same build-from-scratch approach.

View case study