# LogicUtil

> Free online developer tools. Every tool runs client-side in the browser, so pasted text, code and files are never uploaded to a server. No sign-up, no account, no paywall, no usage limits.

LogicUtil is a collection of 32 single-purpose utilities for everyday development tasks: formatting and validating data, encoding and decoding between formats, generating identifiers and secrets, and converting images.

Every tool, the image converter included, runs client-side: images are decoded and re-encoded with the canvas APIs built into the browser, and a batch download is zipped inside the page. The site carries no advertising. Visits are counted by the site's own cookieless statistics, which store no IP addresses, and by Google Analytics, which loads only after the page has finished loading and asks visitors in Europe for consent first; nothing typed into a tool is ever sent.

Each tool page ends with a long-form reference article covering what the format is, how to use the tool, common errors and related tools. Those articles are the most useful part of the site to cite, and every one of them, together with every guide, is available in full as Markdown at https://logicutil.com/llms-full.txt.

Available in 8 languages: en, de, es, pt, fr, fa, ar, ja. English lives at the root; every other language is served under its own prefix, for example https://logicutil.com/de/tool/json-formatter. Persian and Arabic pages are right-to-left.

## Text

- [JSON Formatter](https://logicutil.com/tool/json-formatter): Format, validate, minify and browse JSON as a tree — instantly, in your browser.
- [Regex Tester](https://logicutil.com/tool/regex-tester): Test regular expressions live: matches, capture groups and replace, with a library of 15 ready-made patterns.
- [JSON Converter](https://logicutil.com/tool/json-converter): Convert between JSON, YAML, CSV and XML in any direction, with clear error messages — all in your browser.
- [Text Compare (Diff)](https://logicutil.com/tool/text-diff): Compare two texts and see what changed, line by line and word by word, side by side or as a unified diff.
- [Case Converter](https://logicutil.com/tool/case-converter): Turn text into UPPER CASE, lower case, Title Case, camelCase, snake_case, a URL slug and more, all at once.
- [Word Counter](https://logicutil.com/tool/word-counter): Count words, characters, sentences and reading time as you type, remove duplicate lines, and generate Lorem ipsum.
- [Markdown to HTML Converter](https://logicutil.com/tool/markdown-converter): Convert Markdown to HTML with a live preview, or turn HTML into clean Markdown, including tables and code blocks.

## Encoding

- [Base64 Encoder & Decoder](https://logicutil.com/tool/base64-encoder): Encode and decode Base64 for text, files and images — with data URIs, in your browser.
- [URL Encoder & Decoder](https://logicutil.com/tool/url-encoder): Percent-encode and decode URLs, query strings and parameters, in your browser.
- [Number Base Converter](https://logicutil.com/tool/number-base-converter): Convert between binary, decimal, hex, octal and any base up to 36, and turn text into binary or hex and back.
- [HTML Entity Encoder & Decoder](https://logicutil.com/tool/html-entity-encoder): Escape text for HTML with named, decimal or hex entities, or decode any HTML entity back to plain text.

## Generator

- [UUID Generator](https://logicutil.com/tool/uuid-generator): Generate v4, v7, v1, v3 and v5 UUIDs — one or a thousand at once — and inspect any UUID.
- [Password Generator](https://logicutil.com/tool/password-generator): Generate strong, random passwords with a strength meter — secure, free, in your browser.
- [QR Code Generator](https://logicutil.com/tool/qr-code-generator): Create free QR codes for URLs, Wi-Fi, contacts and text — or read a QR code from an image, in your browser.
- [CSS Generator](https://logicutil.com/tool/css-generator): Design gradients, box shadows and rounded corners visually and copy the CSS they need.
- [Meta Tag Generator](https://logicutil.com/tool/meta-tag-generator): Create SEO meta tags, Open Graph and X card tags, and preview how the page looks on Google and in social shares.

## Image

- [Image Converter](https://logicutil.com/tool/image-converter): Convert images to WebP, PNG, JPG or PDF in bulk, or compress them to a target size in KB — all in your browser.
- [EXIF Viewer & Remover](https://logicutil.com/tool/exif-viewer): See the hidden metadata in your photos, including GPS location, and remove it without losing any image quality.
- [QR Code Reader](https://logicutil.com/tool/qr-code-reader): Read QR codes from an image, a screenshot or your camera, and see links, Wi-Fi details and contacts before you use them.

## Developer

- [Color Converter](https://logicutil.com/tool/color-converter): Convert HEX, RGB, HSL, HSV, CMYK and OKLCH, build palettes and check contrast — in your browser.
- [Hash Generator](https://logicutil.com/tool/hash-generator): MD5, SHA-1, SHA-256 and SHA-512 hashes for text or files, bcrypt, and a checksum checker — in your browser.
- [Unix Timestamp Converter](https://logicutil.com/tool/timestamp-converter): Convert Unix timestamps to readable dates and back, in any time zone, with the live epoch.
- [JWT Decoder](https://logicutil.com/tool/jwt-decoder): Decode JSON Web Tokens locally and verify their signature with your secret or public key — nothing leaves your browser.
- [Unused CSS Remover](https://logicutil.com/tool/unused-css-remover): Keep only the CSS a page uses, from a Chrome Coverage export or from the HTML and the stylesheet. Everything runs in your browser.
- [Code Formatter & Minifier](https://logicutil.com/tool/code-formatter): Beautify or minify HTML, CSS, JavaScript and SQL, with the language detected for you — all in your browser.
- [Cron Expression Explainer](https://logicutil.com/tool/cron-expression): Read any cron expression in plain language, field by field, and see exactly when it will run next.
- [Subnet Calculator](https://logicutil.com/tool/subnet-calculator): Calculate the network, host range and mask of any IPv4 or IPv6 subnet, and split a network into smaller ones.
- [User-Agent Parser](https://logicutil.com/tool/user-agent-parser): Read the browser, operating system and device in any user-agent string, see your own, and recognise search engine and AI crawlers.
- [JSON to Types](https://logicutil.com/tool/json-to-types): Turn a JSON sample into TypeScript interfaces, Go structs, Python models, C# classes, Rust structs or a JSON Schema.

## PDF

- [PDF Tools](https://logicutil.com/tool/pdf-tools): Merge, split and organize PDF files in your browser: extract, delete, rotate and reorder pages without uploading anything.
- [PDF Converter](https://logicutil.com/tool/pdf-converter): Turn PDF pages into JPG, PNG or WebP images, or extract the text, right in your browser without uploading the file.
- [PDF Compressor](https://logicutil.com/tool/pdf-compressor): Reduce the size of a PDF by recompressing its pictures while keeping the text, or go further by turning pages into images, without uploading the file.

## Task pages

Single-purpose entry points into the tools above, each opened with the right settings and with its own short guide. Available in: en, de, es, pt, fr, fa, ar, ja.

- [PNG to JPG Converter](https://logicutil.com/tool/png-to-jpg): Shrink PNG screenshots and photos into JPG files, in bulk, without sending them to a server.
- [WebP to JPG Converter](https://logicutil.com/tool/webp-to-jpg): Turn WebP images into JPG files that open everywhere, in bulk, without uploading them anywhere.
- [JPG to PNG Converter](https://logicutil.com/tool/jpg-to-png): Turn JPG and JPEG photos into lossless PNG files right in your browser, one at a time or in a batch.
- [WebP to PNG Converter](https://logicutil.com/tool/webp-to-png): Convert WebP images to PNG with transparency preserved, in your browser and in bulk.
- [PNG to WebP Converter](https://logicutil.com/tool/png-to-webp): Make PNG images lighter for the web by converting them to WebP, transparency included, without uploading them.
- [JPG to WebP Converter](https://logicutil.com/tool/jpg-to-webp): Convert JPG photos to WebP for lighter, faster web pages, with the quality under your control and nothing uploaded.
- [Favicon Generator](https://logicutil.com/tool/favicon-generator): Build a favicon.ico from any image, with every size a browser asks for packed into one file.
- [Compress Images](https://logicutil.com/tool/compress-image): Make photos and screenshots smaller without changing their format, and without sending them anywhere.
- [Resize Images](https://logicutil.com/tool/resize-image): Change the dimensions of one photo or thirty, keep their formats, and never upload a file.
- [Compress an Image to 100 KB](https://logicutil.com/tool/compress-image-to-100kb): Bring a photo, a scan or a signature under 100 KB for an application form, without guessing a quality setting.
- [AVIF to JPG Converter](https://logicutil.com/tool/avif-to-jpg): Turn AVIF images into JPG files that every app, editor and upload form accepts, without sending them anywhere.
- [AVIF to PNG Converter](https://logicutil.com/tool/avif-to-png): Turn AVIF images into lossless PNG files, transparent background included, right in your browser.
- [Image to PDF Converter](https://logicutil.com/tool/image-to-pdf): Combine photos, scans and screenshots into a single PDF, one page per image, without uploading them anywhere.
- [JPG to PDF Converter](https://logicutil.com/tool/jpg-to-pdf): Turn JPG photos and scanned pages into a single PDF on A4 paper, ready to email, upload or print.
- [PNG to PDF Converter](https://logicutil.com/tool/png-to-pdf): Put PNG screenshots, diagrams and scans into a PDF with every pixel intact, so small text stays sharp.
- [HEX to RGB Converter](https://logicutil.com/tool/hex-to-rgb): Paste a HEX color code and get its RGB values, ready to copy as rgb() or rgba().
- [RGB to HEX Converter](https://logicutil.com/tool/rgb-to-hex): Enter red, green and blue values or a CSS rgb() string and get the matching HEX color code.
- [HEX to HSL Converter](https://logicutil.com/tool/hex-to-hsl): Turn a HEX color code into hue, saturation and lightness, the notation that makes color variants easy.
- [Color Contrast Checker](https://logicutil.com/tool/color-contrast-checker): Measure the WCAG contrast ratio of any text and background pair and find a passing shade when it falls short.
- [MD5 Hash Generator](https://logicutil.com/tool/md5-generator): Get the 32-character MD5 hash of text or a file instantly, computed locally in your browser.
- [SHA-256 Hash Generator](https://logicutil.com/tool/sha256-generator): Compute the SHA-256 hash of any text or file and check it against a published checksum, without uploading anything.
- [SHA-512 Hash Generator](https://logicutil.com/tool/sha512-generator): Get the 128-character SHA-512 hash of text or a file, computed in your browser and ready to compare.
- [SHA-1 Hash Generator](https://logicutil.com/tool/sha1-generator): Get the 40-character SHA-1 hash of text or a file, computed locally with your browser's own crypto engine.
- [File Checksum Checker](https://logicutil.com/tool/file-checksum): Check that a downloaded file is intact by comparing its hash with the checksum the publisher lists, all in your browser.
- [Bcrypt Hash Generator and Checker](https://logicutil.com/tool/bcrypt-generator): Make a bcrypt hash for a password, or test whether a password matches a stored hash, without anything leaving your browser.
- [UUID v4 Generator](https://logicutil.com/tool/uuid-v4-generator): Create random version 4 UUIDs from your browser's secure random number generator, one at a time or in bulk.
- [UUID v7 Generator](https://logicutil.com/tool/uuid-v7-generator): Create time-ordered version 7 UUIDs that sort by creation time, ideal for database primary keys.
- [GUID Generator](https://logicutil.com/tool/guid-generator): Create new GUIDs in the format Windows, .NET and SQL Server tools expect, one at a time or a thousand at once.
- [Base64 Decoder](https://logicutil.com/tool/base64-decode): Paste a Base64 string and see it decoded as you type: readable text, an image preview or a file to download.
- [Image to Base64 Converter](https://logicutil.com/tool/image-to-base64): Turn an image into a Base64 string or a ready-to-paste data URI, without uploading it anywhere.
- [Base64 to PDF Converter](https://logicutil.com/tool/base64-to-pdf): Turn a Base64-encoded PDF from an API or a database back into a document you can read and save.
- [URL Decoder](https://logicutil.com/tool/url-decode): Paste a percent-encoded URL or query string and read it decoded as you type, UTF-8 characters included.
- [JSON Validator](https://logicutil.com/tool/json-validator): Paste JSON to check it against the standard, with the exact error message and position when something is wrong.
- [JSON Minifier](https://logicutil.com/tool/json-minify): Strip whitespace from JSON and get a compact, valid single line, minified as you paste.
- [Wi-Fi QR Code Generator](https://logicutil.com/tool/wifi-qr-code-generator): Make a QR code that connects phones to your Wi-Fi in one scan, created in your browser so the password never leaves your device.
- [vCard QR Code Generator](https://logicutil.com/tool/vcard-qr-code-generator): Build a contact-card QR code for business cards, email signatures and name badges, free and without a watermark.
- [Strong Password Generator](https://logicutil.com/tool/strong-password-generator): A secure random password built from your browser's cryptographic random source, with the entropy printed underneath so you can see how strong it really is.
- [Passphrase Generator](https://logicutil.com/tool/passphrase-generator): Several unrelated words picked at random are as strong as a random string and far easier to type from memory; this page builds them from the EFF word list.
- [Random PIN Generator](https://logicutil.com/tool/pin-generator): A PIN nobody can guess from your birthday, drawn digit by digit from your browser's cryptographic random source.
- [Wi-Fi Password Generator](https://logicutil.com/tool/wifi-password-generator): A long random network key with no symbols and no characters anyone can misread, so it holds up when it is typed on a console or read off a card.
- [Timestamp to Date Converter](https://logicutil.com/tool/timestamp-to-date): Turn a Unix timestamp into a readable date in any time zone, with the UTC and ISO 8601 forms beside it.
- [Date to Timestamp Converter](https://logicutil.com/tool/date-to-timestamp): Turn a calendar date and a wall-clock time into a Unix timestamp, read in whichever time zone you choose.
- [Milliseconds to Date Converter](https://logicutil.com/tool/milliseconds-to-date): Read a Unix timestamp in milliseconds as a date, with the sub-second part kept in the ISO 8601 line.
- [Discord Timestamp Generator](https://logicutil.com/tool/discord-timestamp): Build the markup Discord renders in each reader's own time zone, in all nine styles at once.
- [Current Unix Timestamp](https://logicutil.com/tool/current-unix-timestamp): Epoch time right now, in seconds, counting up once a second and ready to copy.
- [JWT Generator](https://logicutil.com/tool/jwt-generator): Sign a JSON Web Token of your own to test an endpoint, with the same twelve algorithms a real issuer uses — and without the key ever leaving your browser.
- [JWT Expiration Checker](https://logicutil.com/tool/jwt-expiration-checker): The exp claim is a Unix timestamp, which tells you nothing at a glance. Paste the token and this page turns it into a date, a time zone you recognise and a plain sentence.
- [JWT Debugger](https://logicutil.com/tool/jwt-debugger): A 401 with a token that looks fine is almost always one of six things. This page shows you the token the way the server reads it, so you can find out which.
- [JavaScript Regex Tester](https://logicutil.com/tool/javascript-regex-tester): Test a pattern with the RegExp engine your JavaScript will run on, so what matches here matches in your code.
- [Regex Find and Replace](https://logicutil.com/tool/regex-replace): Rewrite text with a regular expression and see the result before you run it on real files.
- [URL Regex](https://logicutil.com/tool/url-regex): Find web addresses in text with a short pattern, and see exactly where it stops before you put it in code.
- [JSON to YAML Converter](https://logicutil.com/tool/json-to-yaml): Turn JSON into readable YAML for Kubernetes, Docker Compose or a CI pipeline, instantly and privately.
- [YAML to JSON Converter](https://logicutil.com/tool/yaml-to-json): Turn a YAML file into JSON for an API, a script or a JSON schema check, right in your browser.
- [JSON to CSV Converter](https://logicutil.com/tool/json-to-csv): Turn a JSON array into a CSV table that opens in Excel, Google Sheets or any database import.
- [CSV to JSON Converter](https://logicutil.com/tool/csv-to-json): Turn a CSV export from Excel, Google Sheets or a database into a JSON array ready for code or an API.
- [JSON to XML Converter](https://logicutil.com/tool/json-to-xml): Turn JSON into well-formed XML for a SOAP service, a feed or an older system that only reads XML.
- [XML to JSON Converter](https://logicutil.com/tool/xml-to-json): Turn an XML document, feed or SOAP response into JSON you can use in JavaScript or an API.
- [Binary to Decimal Converter](https://logicutil.com/tool/binary-to-decimal): Type a binary number and read its decimal value, along with hex and octal, as you type.
- [Decimal to Binary Converter](https://logicutil.com/tool/decimal-to-binary): Type a decimal number and see its binary form, grouped into nibbles if you like, as you type.
- [Hex to Decimal Converter](https://logicutil.com/tool/hex-to-decimal): Paste a hex value, with or without 0x, and read it in decimal, binary and octal as you type.
- [Text to Binary Converter](https://logicutil.com/tool/text-to-binary): Turn any text into binary bytes, or decode a row of 0s and 1s back into readable text.
- [Extract Used CSS From a Chrome Coverage Export](https://logicutil.com/tool/coverage-json-to-css): Drop the JSON from the Coverage panel and get back one stylesheet with only the rules the page applied, still inside their media queries.
- [Remove Unused CSS Online](https://logicutil.com/tool/purgecss-online): Paste the HTML and the CSS, and keep only the rules that match something on the page.
- [HTML Formatter](https://logicutil.com/tool/html-formatter): Turn one long line of HTML into neatly indented markup you can read and edit.
- [SQL Formatter](https://logicutil.com/tool/sql-formatter): Turn a one-line query into readable SQL, with each clause on its own line and keywords in the case you like.
- [CSS Minifier](https://logicutil.com/tool/css-minifier): Shrink a stylesheet by removing comments and whitespace, without breaking a single rule.
- [JavaScript Minifier](https://logicutil.com/tool/javascript-minifier): Make a script as small as possible with Terser, the same minifier webpack uses, without sending it anywhere.
- [JavaScript Beautifier](https://logicutil.com/tool/javascript-beautifier): Turn minified or badly formatted JavaScript into code you can actually read.
- [URL Slug Generator](https://logicutil.com/tool/slug-generator): Paste a title and get a clean, readable slug for the web address of a post, product or page.
- [Title Case Converter](https://logicutil.com/tool/title-case-converter): Capitalise a headline the way style guides expect, with short words kept lowercase.
- [Uppercase Converter](https://logicutil.com/tool/uppercase-converter): Change any text to capital letters, or undo Caps Lock by turning it back into lowercase.
- [camelCase Converter](https://logicutil.com/tool/camel-case-converter): Turn words or existing identifiers into camelCase, or into any other naming style your code uses.
- [Character Counter](https://logicutil.com/tool/character-counter): See how many characters your text has, with and without spaces, and whether it fits the limit you are writing for.
- [Remove Duplicate Lines](https://logicutil.com/tool/remove-duplicate-lines): Paste a list and keep each line only once, in its original order or sorted.
- [Lorem Ipsum Generator](https://logicutil.com/tool/lorem-ipsum-generator): Get as much Lorem ipsum filler text as your layout needs, as plain text or ready-made HTML paragraphs.
- [HTML to Markdown Converter](https://logicutil.com/tool/html-to-markdown): Paste HTML from a page, a CMS or an email and get tidy Markdown for a README, a wiki or a static site.
- [Markdown Preview](https://logicutil.com/tool/markdown-preview): See your Markdown rendered as you type, the way GitHub-style Markdown will display it.
- [Escape HTML](https://logicutil.com/tool/html-escape): Make any text safe to put inside HTML, so it is shown as written instead of being read as markup.
- [HTML Entity Decoder](https://logicutil.com/tool/html-entity-decoder): Turn text full of entity codes back into the characters they stand for.
- [Cron Every 5 Minutes](https://logicutil.com/tool/cron-every-5-minutes): The expression */5 * * * * runs a job every five minutes; here it is explained with its next run times.
- [Cron Every Hour](https://logicutil.com/tool/cron-every-hour): The expression 0 * * * * runs a job at the start of every hour; here it is explained with its next run times.
- [Cron Every Day](https://logicutil.com/tool/cron-every-day): The expression 0 0 * * * runs a job once a day at midnight; here it is explained with its next run times.
- [CSS Gradient Generator](https://logicutil.com/tool/css-gradient-generator): Pick colours and an angle, watch the preview, and copy the background CSS.
- [Box Shadow Generator](https://logicutil.com/tool/box-shadow-generator): Set offset, blur and spread with sliders and copy the box-shadow line.
- [Border Radius Generator](https://logicutil.com/tool/border-radius-generator): Round all four corners or each one on its own, and copy the border-radius line.
- [Remove EXIF Data](https://logicutil.com/tool/remove-exif-data): Clean the hidden data out of your photos without losing any quality.
- [Remove Location from a Photo](https://logicutil.com/tool/remove-photo-location): Check whether a photo gives away where it was taken, and remove the location.
- [CIDR to IP Range](https://logicutil.com/tool/cidr-to-ip-range): Enter a CIDR block and see exactly which addresses it covers.
- [Subnet Mask Cheat Sheet](https://logicutil.com/tool/subnet-mask-cheat-sheet): Every IPv4 prefix with its mask and host count, next to a calculator.
- [IPv6 Subnet Calculator](https://logicutil.com/tool/ipv6-subnet-calculator): See the range of an IPv6 prefix, how many /64 networks it holds, and split it.
- [What Is My User Agent?](https://logicutil.com/tool/what-is-my-user-agent): This is the user-agent string your browser sends to every website, and what it says about you.
- [Merge PDF Files](https://logicutil.com/tool/merge-pdf): Put several PDFs into one file, in the order you want.
- [Split PDF](https://logicutil.com/tool/split-pdf): Cut a PDF into separate files: one per page, every few pages or by range.
- [Extract Pages from a PDF](https://logicutil.com/tool/extract-pdf-pages): Save only the pages you need as a new PDF.
- [Delete Pages from a PDF](https://logicutil.com/tool/delete-pdf-pages): Remove blank, duplicate or unwanted pages and keep the rest.
- [Rotate PDF Pages](https://logicutil.com/tool/rotate-pdf): Turn sideways or upside-down pages and save the PDF the right way up.
- [PDF to JPG](https://logicutil.com/tool/pdf-to-jpg): Save the pages of a PDF as JPG images.
- [PDF to PNG](https://logicutil.com/tool/pdf-to-png): Save PDF pages as sharp PNG images.
- [PDF to Text](https://logicutil.com/tool/pdf-to-text): Pull the words out of a PDF to copy, edit or search them.
- [QR Code Scanner](https://logicutil.com/tool/qr-code-scanner): Scan a QR code with your camera, without installing an app.
- [Read a QR Code from an Image](https://logicutil.com/tool/read-qr-code-from-image): Decode a QR code from a photo, a saved image or a screenshot.
- [JSON to TypeScript](https://logicutil.com/tool/json-to-typescript): Turn a JSON sample into TypeScript interfaces.
- [JSON to Go Struct](https://logicutil.com/tool/json-to-go): Turn a JSON sample into Go structs with json tags.
- [JSON to Python Classes](https://logicutil.com/tool/json-to-python): Turn a JSON sample into Pydantic models or dataclasses.
- [JSON to C# Class](https://logicutil.com/tool/json-to-csharp): Turn a JSON sample into C# classes.
- [JSON Schema Generator](https://logicutil.com/tool/json-schema-generator): Create a JSON Schema from a sample document.
- [Open Graph Generator](https://logicutil.com/tool/open-graph-generator): Write the tags that decide how your link looks when it is shared.
- [Twitter (X) Card Generator](https://logicutil.com/tool/twitter-card-generator): Make links to your page show a proper card on X.
- [Google Search Result Preview](https://logicutil.com/tool/google-serp-preview): Check your title and description before Google cuts them.
- [Compress PDF to 100 KB](https://logicutil.com/tool/compress-pdf-to-100kb): Shrink a PDF under 100 KB for strict upload limits.
- [Compress PDF to 1 MB](https://logicutil.com/tool/compress-pdf-to-1mb): Get a PDF under 1 MB with the best quality that fits.
- [Reduce PDF Size](https://logicutil.com/tool/reduce-pdf-size): Make a PDF smaller while the text stays sharp.

## Guides

Standalone explanations of common errors, format comparisons and how-tos, each linking to the tool that does the job. Other languages have their own guides under /{lang}/guides.

- [How to Merge PDF Files Without Uploading Them](https://logicutil.com/guides/merge-pdf-without-uploading): Most online PDF mergers upload your documents to their servers. For contracts, bank statements and ID scans there are better options.
- [Open Graph Tags: How to Control Link Previews](https://logicutil.com/guides/open-graph-tags): When a link is shared on Facebook, LinkedIn, WhatsApp, Slack or X, a few lines in the page's head decide which title, text and picture people see.
- [How to Scan a QR Code on a Laptop or PC](https://logicutil.com/guides/scan-qr-code-on-laptop): A QR code on your own screen cannot be scanned with the phone in your hand if the phone is the screen, and a laptop has no camera app for it. Here are the ways that work.
- [How to Type an API Response in TypeScript](https://logicutil.com/guides/typescript-types-from-json): fetch gives you data typed as any, which switches TypeScript off exactly where bugs come from. Here is how to give API data a real type, quickly and safely.
- [How to Turn an Elementor Page Into Plain HTML and CSS](https://logicutil.com/guides/elementor-to-html): Elementor already sends the browser plain HTML and CSS; the job is to save that output, cut the CSS down to what the page uses, and replace the few parts that need WordPress.
- [Base64 vs Base64URL: What Changes and When to Use Each](https://logicutil.com/guides/base64-vs-base64url): Base64URL is standard Base64 with two characters replaced, - for + and _ for /, and usually without the = padding.
- [Convert an Image to JPG: WebP, PNG and iPhone Photos](https://logicutil.com/guides/convert-image-to-jpg): JPG is the most widely accepted image format; here is when and how to turn any image into a real JPG without installing software and without uploading anything.
- [Discord Timestamps: Syntax, Styles and Examples](https://logicutil.com/guides/discord-timestamps): A Discord timestamp is a Unix time in seconds plus a style letter, and every reader sees it in their own time zone and locale.
- [encodeURI vs encodeURIComponent: Which One to Use](https://logicutil.com/guides/encodeuri-vs-encodeuricomponent): encodeURIComponent encodes 11 characters that encodeURI leaves alone, and those 11 characters decide whether a value stays inside its parameter.
- [Invalid Base64 String: Why Decoding Fails and How to Fix It](https://logicutil.com/guides/invalid-base64-string): A Base64 decoder rejects a string for one of three reasons: a character outside the alphabet, a length that cannot be right, or padding in the wrong place.
- [JSON Tutorial: Syntax, Rules and Working With JSON in JavaScript and Python](https://logicutil.com/guides/json-tutorial): JSON is the simplest and most widely used format for exchanging data; with a few short rules and two functions in each language, you can read, create and store any data.
- [Unexpected Token in JSON: What It Means and How to Fix It](https://logicutil.com/guides/json-unexpected-token): This error means the text you tried to parse is not JSON. The token it names usually tells you exactly what you received instead.
- [JWT vs Session Cookies: How They Differ and When to Use Each](https://logicutil.com/guides/jwt-vs-session-cookies): A session cookie is a key to state kept on the server; a JWT carries signed state to the server. That one difference drives every trade-off.
- [How to Make a Free QR Code That Never Expires: Links, Wi-Fi and Location](https://logicutil.com/guides/make-qr-code): A QR code whose content is written directly into the code itself never expires; here is how to make one for each use and make sure it scans reliably.
- [MD5 vs SHA-1 vs SHA-256: Which Hash Should You Use?](https://logicutil.com/guides/md5-vs-sha1-vs-sha256): Use SHA-256 for anything security-related; MD5 and SHA-1 are only acceptable where nobody gains anything by forging a matching hash.
- [How to Reduce Image Size to 200 KB Without Visible Quality Loss](https://logicutil.com/guides/reduce-image-size): Two things set the size of a photo, its dimensions and its compression quality; get those two right and a multi-megabyte phone photo shrinks in seconds to a size upload forms accept.
- [Regex for Email Validation: A Practical Pattern and Its Limits](https://logicutil.com/guides/regex-email-validation): No regex can tell you whether an address works. A short pattern catches typos; a confirmation email proves the rest.
- [Regex for Numbers, Phone Numbers and IP Addresses](https://logicutil.com/guides/regex-phone-ip-numbers): Copy-ready patterns for numeric input, phone numbers and IP addresses, each tested, with notes on where a parser or library does the job better.
- [What Is a Strong Password, and How Do You Create One That Is Really Secure?](https://logicutil.com/guides/strong-password): A password does not get its strength from looking complicated but from its length and randomness; this guide shows how to create one that is practically impossible to guess, without having to memorise it.
- [Unexpected End of JSON Input: What It Means and How to Fix It](https://logicutil.com/guides/unexpected-end-of-json-input): The parser ran out of text before it found a complete value, and in most cases that is because there was no text at all.
- [URL Encoding: How Percent-Encoding Works](https://logicutil.com/guides/url-encoding): URL encoding replaces every byte that cannot appear as-is in a web address with a % sign followed by the value of that byte in hexadecimal.
- [UUID vs GUID: What Is Actually Different](https://logicutil.com/guides/uuid-vs-guid): GUID is Microsoft's name for a UUID. The differences you meet in practice are text formatting, byte order when the value is stored as 16 bytes, and SQL Server's sort order.
- [UUID vs ULID vs Nano ID vs Auto-Increment IDs](https://logicutil.com/guides/uuid-vs-ulid-vs-nanoid): Five common ID schemes compared on what matters in practice: size, ordering, collision odds, database behaviour and what an ID gives away.
- [WebP vs PNG vs JPG: Choosing the Right Image Format](https://logicutil.com/guides/webp-vs-png-vs-jpg): JPG is for photos that must open anywhere, PNG is for exact pixels, and WebP does both jobs in smaller files on the web.

## Site

- [All tools](https://logicutil.com/tools): index of every tool.
- [Text category](https://logicutil.com/category/text): tools grouped under text.
- [Encoding category](https://logicutil.com/category/encoding): tools grouped under encoding.
- [Generator category](https://logicutil.com/category/generator): tools grouped under generator.
- [Image category](https://logicutil.com/category/image): tools grouped under image.
- [Developer category](https://logicutil.com/category/developer): tools grouped under developer.
- [PDF category](https://logicutil.com/category/pdf): tools grouped under pdf.
- [About](https://logicutil.com/page/about)
- [Privacy Policy](https://logicutil.com/page/privacy-policy)
- [Terms](https://logicutil.com/page/terms)
- [Sitemap](https://logicutil.com/sitemap.xml): every URL in every language, with hreflang alternates.

## Languages

Every tool page, category page and article exists in each of these languages. Replace the language prefix in any URL above to reach the same tool in another language.

- [English (en)](https://logicutil.com/tools)
- [Deutsch (de)](https://logicutil.com/de/tools)
- [Español (es)](https://logicutil.com/es/tools)
- [Português (pt)](https://logicutil.com/pt/tools)
- [Français (fr)](https://logicutil.com/fr/tools)
- [فارسی (fa)](https://logicutil.com/fa/tools)
- [العربية (ar)](https://logicutil.com/ar/tools)
- [日本語 (ja)](https://logicutil.com/ja/tools)