JSON Duplicate Key Checker – Online Find Repeated Keys
Paste JSON and instantly see if any object has duplicate keys. Quick syntax spotter.
UD5 Toolkit
Generate short, unique, non-sequential IDs from numbers, or decode them back.
Hashid is a small library that generates short, unique, non-sequential IDs from positive integers. It’s often used to hide real database IDs in URLs or for creating friendly public identifiers.
No, Hashids is not encryption. It’s an obfuscation technique. Anyone with the salt (and alphabet) can decode the IDs. Do not use it as a security measure.
No. Without the exact salt and alphabet used during encoding, decoding will either fail or return wrong numbers. Always store your salt securely.
The salt shuffles the character mapping, and minimum length pads the output. Even a tiny change in either parameter produces a completely different hashid.
Only positive integers (0, 1, 2, …) and arrays of positive integers. Negative numbers and floats are not supported.
Paste JSON and instantly see if any object has duplicate keys. Quick syntax spotter.
Decode the header and payload of a JSON Web Token (JWT) without verifying the signature. Inspect claims securely on the client side. Great for developers.
Choose from a list of 50 values and narrow down to your top 5. Understand what drives you. Private.
Select logical operators (AND, OR, XOR, NAND) and generate a complete truth table. Handy for digital logic.
Paste text with highlights (e.g., from Apple Books) and extract only the highlighted lines. Save as list.
Simple interface for kids to log reading minutes and pages. Add book titles. Print weekly report. Local.
Generate a random book title with a subtitle. Good for writing prompts or just for laughs.
Convert Markdown to styled HTML that retains formatting when pasted into Google Docs or Word. Headings, bold, lists. Client‑side.
Paste text and align it left, center, right, or fully justify by inserting spaces. Simple formatting helper. Pure browser.
Take a lighthearted inventory of your character strengths (not official VIA). Self-reflection tool. All in browser.
Click for a warm, quirky compliment to brighten someone's day. Great for social media and morale boosting.
Enter a city to get current UV index forecast using open data (with local caching). Understand sun protection needs. No personal location used.
Query the permission state of camera, microphone, geolocation, and more. See the response and learn the API.
Pick a contact from the device’s address book (mobile). Read name, email, and phone. All permission‑based. Privacy safe.
Answer questions about your page (image size, caching, fonts) and get a tailored list of optimization tips. Manual audit helper.
See the healthy weight range for your height using standard BMI chart. Gender‑specific data. Quick reference.
Touch the screen and see the exact coordinates, radius, and force of each touch point. Indispensable for mobile web devs.
Simulate zenithal priming and contrast/speed paints over a 3D bust. Understand light and shadow placement before you paint. Great for tabletop miniatures.
Force more or less contrast and see how your page adapts. Test your CSS media queries for accessibility.
Encrypt or decrypt text using the classical 5x5 Polybius square. Excludes J or merges I/J.
Paste an enciphered text and instantly see all 25 possible shifts. Highlight the most plausible.
Encode or decode data to/from Base58 (Bitcoin alphabet). Useful for cryptocurrency address generation testing. Fully local, no data sent.
Encode or decode a string for use in a URL query parameter. See the raw and encoded versions. Dev tool.
Paste text with \uXXXX or \xXX escape sequences and decode to readable characters. Works for all Unicode planes.
Decode an image progressively using the ImageDecoder API. See partial results and metadata. Modern alternative to <img>.
Encode latitude/longitude into a geohash string and decode a geohash back to coordinates with precision info. Local algorithm.
Encode any file into a Base64 string that you can copy, or decode a Base64 string back to a downloadable file. Pure frontend.
Convert your text into a string of emojis using a simple substitution cipher. Share secret messages that look fun. Decode them with the same tool. All local.
Paste a JSON Web Token and decode its header and payload. Verify signature if you provide the secret. Fully local.
Hide your email address from scrapers by encoding it using HTML entities and CSS tricks. Still clickable for real users. Local generator.