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Web tools that just work
The tools we use on every Stacklumen engagement — SEO auditing, Open Graph previewing, contrast checking — packaged for everyone.
SEO + AEO
SEO + AEO Audit
Paste a URL. Get a graded report on title, meta, canonical, OG, JSON-LD, h1, robots, sitemap, and llms.txt — plus a check that templated pages have distinct titles, sampled across two pages so template-level duplicates actually surface.
Open Graph Preview
Render any URL the way Slack, iMessage, Twitter, LinkedIn, Discord, and Google would.
robots.txt + llms.txt
Decide what may index you, what may cite you and what may train on you — across 34 named crawlers — then publish the llms.txt that tells answer engines which pages matter.
Content + Schema
JSON-LD Generator
Form-driven generator for Organization, FAQPage, Product, Article, BreadcrumbList and more — copy-paste ready.
Schema Validator
Pulls every JSON-LD block from a page and checks each entity against schema.org + Google rich-result requirements, flagging missing required and recommended properties.
Accessibility
Contrast Checker
Paste a foreground + background. Get ratio, pass status, and a one-click brand-safe suggestion.
Accessibility Audit
Runs the axe-core accessibility rules via Lighthouse. Grades contrast, names & labels, ARIA and structure, with failing elements and a branded PDF.
Landmark Map
Draws the ARIA landmark tree and heading outline of any URL as a diagram — main, banner, contentinfo, navigation and every labelled region, in the order and nesting they are served. Flags the structural faults a visual check cannot see: a missing main, duplicate landmarks with no accessible name, and skipped heading levels.
Webflow
Webflow Embed Sizer
Paste an embed → minified HTML/CSS/JS, real character + KB size, gzipped size, and whether it fits inside Webflow's embed cap.
Site Maintainability Audit
Reads the compiled stylesheet, not just the markup. Flags auto-generated class names, brittle selector chains, CSS inlined where it cannot be cached, and layouts fixed in px that ignore a reader's font-size setting. None of it affects ranking; all of it decides how expensive the site is to change.
Images
HEIC Converter
Drop HEIC files and get JPG, PNG or WebP back. Decoding and re-encoding run entirely in the browser with WebAssembly — the files never leave the device.
PNG to SVG
Traces a PNG or JPG into clean SVG paths in the browser, with control over colour count and detail — for logos and flat artwork you only have as pixels.