How to Compare 2 Websites SEO Side by Side in Real Time (Free Chrome Extension)

ian_silas — Fri, 04 Sep 2026 07:18:21 +0000

When optimizing a landing page or an article, we’ve all been there:

You target a primary keyword, but a competitor consistently outranks you on Google. You open their page, inspect the elements, jump back to your own CMS, and ask yourself:

Why is Google ranking their page higher than mine?
Is their content deeper (word count)?
How is their Heading hierarchy (H1-H3) structured compared to mine?
Which exact ranking keywords are they capturing that my page completely missed?

Most existing online comparison tools force you into an annoying workflow: copy URL A, copy URL B, open a third-party website, paste both, wait for a queue, only to get a dated report from 2012.

To solve this, I built a lightweight, developer-friendly solution: Compare 2 Websites SEO.

🛑 The Pain Point with Traditional SEO Site Comparison

If you've ever tried to compare two websites SEO performance manually, you know the struggle:

Tab Hell: Switching back and forth between your landing page and the competitor’s live site.
Surface-level Metrics: Most free tools only inspect superficial HTML tags without understanding content density or real-time SERP rankings.
Keyword Gap Blindness: You can see their text, but you don't know which specific search queries are driving their organic Google US traffic.

I wanted something that lives directly in the browser's side panel—extracting competitor DOM data in sub-seconds while keeping my baseline landing page locked for instant side-by-side auditing.

⚡ How It Works: Instant Side-by-Side Breakdown

The extension runs right in your browser side panel without cluttering your main screen:

1. Zero-Cost Instant On-Page Audit

When you browse a competitor's page, the tool inspects their active DOM and parses your target landing page simultaneously:

Clean Article Body Word Count: Filtered for boilerplates (headers, footers, nav scripts).
Heading Tree Inspection (H1 - H3): Spot structural flaws and heading hierarchy differences at a glance.
Image Accessibility (alt tags): Instantly highlights how many visual assets are missing SEO descriptions.
Top Keyword Frequency & Density: Understand what topics the competitor is heavily emphasizing.

2. Deep Keyword Gap Analysis (SERP Rank Diff)

Beyond raw on-page HTML, the tool integrates deep SERP ranking metrics to uncover:

Keywords your competitor ranks for in Google US Top 100, but your target landing page is missing.
Exact Rank Position (#1 - #100) for both pages head-to-head.
Monthly Search Volume, Keyword Difficulty (KD), and CPC.
One-Click Export: Download differences in structured CSV or plain TXT format.

🛠️ Tech Stack & Implementation Details

For fellow developers interested in how it was built:

Manifest V3 Side Panel API: Delivers a native IDE/panel-like workflow without breaking your browsing viewport.
Mozilla Readability & Custom Cleaners: Removes noisy UI boilerplates and advertisements to get accurate raw body word counts.
Local Caching Mechanism: Implements a 24-hour smart cache layer for SERP data queries to prevent duplicate API hits and minimize latency.
Client-Side Fallbacks: Inspects client-rendered SPA containers vs. static HTML to alert users if dynamic hydration affects parsed word count.

🚀 Try It Out

If you frequently optimize landing pages, run competitor teardowns, or conduct on-page technical audits, you can install the extension directly from the Chrome Web Store:

👉 Install Chrome Extension: Compare 2 Websites SEO - Content Gap & Side-by-Side Tool

(New users receive free analysis credits upon Google Sign-In).

Feedback, feature requests, and bug reports from the DEV community are warmly welcome! How do you currently run your competitor SEO comparisons? Let me know in the comments below!

How I Built a Chrome Extension to Find Low-Competition "Blue Ocean" SEO Keywords

ian_silas — Tue, 25 Aug 2026 11:55:59 +0000

As an indie hacker, doing SEO for side projects can be frustrating. Most high-volume keywords in 2026 are already heavily guarded by authority domains, and enterprise SEO suites cost $100+ per month—way too expensive for validating a small product.

To solve this, I focused on a different approach: Reverse-engineering direct competitors to uncover "Blue Ocean" keywords (search queries with high commercial intent and minimal keyword difficulty).

Instead of doing manual spreadsheet lookups, I built a lightweight Chrome extension called Competitor Keyword Finder.

Why Blue Ocean Keywords Matter for Builders

A typical mistake when launching a project is targeting broad, high-volume terms. For indie creators, the sweet spot is queries where:

Keyword Difficulty (KD) is low (< 35): Minimal backlink profile required to get indexed and ranked.
Search Intent is commercial/informational: Visitors are actively looking for tools or specific workflows.
Competitors have gaps: Legacy pages that rank but offer outdated UX or sparse answers.

How the Opportunity Algorithm Works

Rather than just showing raw numbers, the tool calculates an automated Blue Ocean Score (0–100) by evaluating:

Search Volume vs. KD ratio
Cost-per-Click (CPC) indicating advertiser demand
Actionable Tier Classification:
- Tier S & Tier A: Prime low-competition keywords ready for immediate content or product landing pages.
- Tier B: Ideal for long-tail FAQ sections and documentation.
- Tier C: High-competition terms to skip.

The extension also supports localized data across 9 global regions (US, Japan, Germany, Taiwan, France, Spain, South Korea, Brazil, Saudi Arabia) and allows 1-click CSV export.

Tech Stack & Workflow

Frontend: Manifest V3 Chrome Extension, Tailwind CSS
Backend: Cloudflare Workers (edge compute) & Serverless data pipelines
Pricing Model: No locked-in subscriptions. 5 free searches upon install, followed by a pay-as-you-go top-up starting at $5.

If you're building a niche site, SaaS, or blog, feel free to give it a spin:

👉 Install Competitor Keyword Finder on Chrome Web Store

Any feedback on the UI or feature suggestions is warmly welcomed!

DEV Community: ian_silas