Free Ecommerce Tools That Run in Your Browser
Calculators and checkers we built for our own work and published as-is. No signup, no data collected, every rate and rule visible and editable. Use them, then read the guide behind each one.
Pick a Tool, Get a Number
Amazon FBA Fee Calculator
Size tier from packaged dimensions, 2026 fulfillment fee by price band, referral fee, storage, ad spend, returns, and net margin per unit. Every rate editable.
AI Crawler Checker
Enter a URL and see whether GPTBot, ClaudeBot, PerplexityBot, Googlebot and 14 more are allowed, blocked in robots.txt, or blocked by a firewall, plus llms.txt presence.
llms.txt Generator
Build a valid llms.txt from your brand summary and key pages, copy or download it, then follow the WordPress or Shopify install steps.
Amazon Listing Character Counter
Live counts against the 75-character title limit, 125-character Item Highlights, bullets, 250-byte search terms and description, with flags for promotional words and banned symbols.
Three Rules for Every Tool Here
Nothing leaves your browser
Inputs are processed in JavaScript on the page. No account, no email gate, nothing stored. If a tool ever needs to fetch something (a crawler checker reading another site's robots.txt), the page says exactly what is sent.
Every rate and rule is visible and dated
Fee cards and platform limits change. Each tool shows the date its data was verified, links the source, and lets you edit the numbers to match what you see in your own seller account.
Each tool has a guide behind it
A calculator gives a number; the guide explains what to do with it. Every tool links to the long-form article it was built from, and the guides link back.
Want Us to Run the Numbers With You?
Book a free call and bring a product. We will work through fees, margin, and what to fix first, live.