20 Free, No-Signup Web Tools Every Developer Should Bookmark fastestchecker.com
Every dev has a mental list of "quick check" sites they reach for what's my IP, is this JSON valid, how big is this image after I resize it. The annoying part is that half of them make you sign up, sit through an ad-gated redirect, or upload your data to some sketchy server just to run a client-side operation that could've happened in your browser.
I put together a list of the tools I actually keep bookmarked, mostly pulled together in one place at FastestChecker.com — free, no account required, and most of it runs client-side. Sharing the breakdown by category in case it saves someone else a few tabs.
Network & Domain Tools
IP Checker — your current public IPv4/IPv6 address, useful for confirming what your server or API actually sees behind a proxy.
Website Location Checker — find out where a site is actually hosted, handy when you're debugging latency or picking a region for your own deployment.
Domain Age Checker — quick way to sanity-check a domain's history before you trust a link or evaluate a backlink source.
Internet Speed Test — no flash, no forced app install, just a straight bandwidth check.
Security & Dev Utilities
Password Generator — configurable length/character sets, generated client-side so nothing gets transmitted.
Email Validator — syntax + MX record checks in one click (I wrote up how this actually works under the hood [in a separate post — PASTE YOUR EMAIL-VALIDATION POST URL HERE] if you want the technical breakdown).
JWT Decoder — paste a token, read the header/payload without pasting your auth token into a random site you don't trust.
Test Card Generator — Luhn-valid dummy card numbers for Stripe/PayPal sandbox testing. Not real cards, just structurally valid test data.
Text & Content Tools
- Word Counter — words, characters, reading time — the basics done fast.
- Text Case Converter — camelCase, snake_case, PascalCase, Title Case, all in one place.
- Markdown Editor — live preview, no account, useful for drafting a README before you commit it.
- Text Extractor / OCR — pull text out of a screenshot instead of retyping an error message from an image.
QR, Barcode & Image Tools
QR Code Generator — including Wi-Fi QR codes, which is a nice trick for office setups.
Barcode Generator — UPC/EAN generation for small projects that need one without a full POS system.
Image Resizer — resize without a Photoshop round trip.
Image Color Picker — grab a hex code straight from a screenshot or reference image.
Website & SEO Analysis
Traffic Checker rough traffic estimates for competitor research.
PageSpeed Checker Core Web Vitals without digging through the full Search Console UI.
A Couple Extras
Loan Calculator — not dev-related, but useful enough to mention.
Stylish Name Generator — mostly for gaming handles, but occasionally handy for generating placeholder usernames in test data.
Why This List Instead of Individual Sites
Nothing here is doing something no other tool does — the value is just not needing 15 different tabs, accounts, and ad-walls to do routine checks. If you already have a favorite tool for one of these, no argument from me. But if you're missing one of these from your bookmarks bar, FastestChecker.com is worth a look.
FAQ
Do any of these tools require an account?
No everything on the list runs without sign-up, and most operations (password generation, text conversion, image resizing) happen client-side, so your data isn't sent anywhere to process it.
Is this free to use, or is there a paid tier?
Free, ad-supported. No feature paywalls on the core tools.
Which of these tools is most useful for backend debugging specifically?
The IP Checker and JWT Decoder get the most day-to-day use for debugging auth and networking issues — both let you inspect exactly what's being sent/received without spinning up extra tooling.
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