All-in-one SEO & Developer Tools

A complete toolkit of free browser-based tools. No sign-up, no data collection.

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Every tool on this page was built to replace a free tool I used to reach for and got tired of, whether because they required sign-ups, served ads, were retired (Twitter's Card Validator), or hid results behind paywalls. Each tool runs entirely in your browser where possible, or processes in memory and discards immediately when server processing is needed.

SEO Suite

One audit, many views. Drop a URL into any of these and the result is cached for 10 minutes, so you can cross-link into the other views without re-fetching.

SEO Audit

Paste any URL, get a scored on-page SEO report across 25 checks. Tabs for headings, social tags, images, links, schema. Includes a ready-to-paste AI prompt to fix the issues for you.

Schema Markup Checker New

JSON-LD deep audit with field-by-field Required/Recommended/Optional classification and an approximate preview of how the rich result would render in Google. Side-by-side current vs potential.

Social Share Preview New

See exactly how your page will appear when shared on Facebook, X/Twitter, LinkedIn, WhatsApp, Slack, Discord, iMessage and Reddit. No Facebook login. Replaces the retired Twitter Card Validator.

HTML Compliance Checker New

Strict W3C-style validator. Every line of HTML that isn't 100% to spec (obsolete elements, unquoted attributes, self-closed non-void tags, missing alt or lang, duplicate IDs) with a concrete example and the fix.

JSON-LD Generator New

Fill out a form → get pasteable JSON-LD for Article, Product, FAQ, HowTo, Event, Recipe, LocalBusiness, Organization, Breadcrumb or Person. Flows directly into the Schema Checker to verify.

Design & Accessibility

Visual palette and accessibility tooling: design a palette in one tool, verify it in the other.

Colour Scheme Designer

Pick a base colour and generate palettes using complementary, triadic, analogous and other harmony modes. Export as CSS variables.

WCAG Contrast Checker New

Instant WCAG 2.1 AA / AAA pass-fail for any foreground/background pair. Normal text, large text and UI components. Suggests the nearest passing colour.

Image Optimiser

Convert images to AVIF, WebP, JPEG and PNG. Compare sizes across formats and quality levels, then download individually or as a ZIP with picture element HTML.

Developer Utilities

Daily-driver tools for writing, escaping and converting code.

String & Code Converter

Convert HTML/text to C#, JavaScript, JSON, Base64 or URL-encoded strings. JSON prettify and minify. Handles the quoting and escaping rules between languages.

SQL Reference

Concise reference of the SQL joins, window functions and common patterns I reach for when the answer needs to be typed in the next minute.

Icon Galleries

Searchable galleries of Font Awesome, Bootstrap and Simple Line Icons: click to copy class names.

E-commerce

Tools for anyone who sells online, starting with eBay and growing.

eBay Fee Calculator New

UK 2026 rates. Calculate final value fee, per-order fee, international fee, promoted listings fee and your net take-home profit in seconds.

eBay Sales History Viewer

Retrieve the full sales history for any eBay listing using the legacy endpoint that was removed from public view in 2023.

About this toolkit

The SEO Suite shares a single cached analysis: drop a URL into SEO Audit, Schema Checker or Social Share Preview and the page is fetched once, then cached for 10 minutes. Switching between views is instant and doesn't count against the rate limit. Every tool runs a polite, identifiable user agent (chedgzoy-seo-audit/1.0) and obeys robots.txt.

The image optimiser uses SixLabors ImageSharp for JPEG, WebP and PNG encoding and libvips for AVIF via the AV1 codec. The contrast checker and JSON-LD generator run 100% client-side; data never leaves your browser.

Privacy: no analytics track individual tool use. Rate limits (10 audits per hour per IP for SEO tools) exist only to prevent abuse, and legitimate use won't hit them. If you'd like to support the work, there's a Buy Me a Coffee link at the top of the page.