Frequently Asked Questions

What is OkTools?

OkTools is a free, browser-based suite of developer utilities. It provides 22 powerful tools across four categories — Security, Data, Converters, and Generators — all running directly in your web browser. No sign-up, no installation, no data collection.

Are OkTools free to use?

Yes, all OkTools are completely free with no sign-up, no registration, and no hidden fees. The platform is sustained by unobtrusive advertisements to keep costs low while providing premium-quality tools to the developer community.

Is my data safe when using OkTools?

Absolutely. All tool operations are performed directly within your browser. Files, text, passwords, JSON data, and other inputs never leave your device unless you explicitly choose to copy or download them. We do not collect, store, upload, or access the data you process with our tools.

Do I need to install anything to use OkTools?

No. OkTools runs entirely in your web browser. Simply visit the website and start using any tool immediately — no downloads, plugins, extensions, or accounts required.

What categories of tools does OkTools offer?

OkTools offers 22 tools across 4 categories:

• Security: Password Generator, Hash Generator, JWT Decoder, SSL Certificate & CSR Decoder
• Data: JSON Formatter & Validator, JSON Compare (Diff), Regex Tester & Explainer, Cron Expression Parser, Text Diff & Compare
• Converters: Base64 Encoder/Decoder, URL Encoder/Decoder, Unix Timestamp Converter, CSV ↔ JSON Converter, Number Base Converter, Color Converter & Contrast Checker, Unit Converter, Time Zone Converter
• Generators: Credit Card Number Generator (test numbers only), UUID Generator, SSN Generator, Lorem Ipsum Generator, QR Code Generator

Can I use OkTools on my mobile device?

Yes. OkTools is fully responsive and works on desktops, tablets, and mobile devices. The interface adapts to your screen size for the best experience regardless of device.

Which browsers are supported?

OkTools works on all modern browsers including Chrome, Firefox, Safari, and Edge. For the best experience, we recommend keeping your browser updated to the latest version.

How does the Password Generator work?

The Password Generator creates strong, random passwords using your specified parameters. You can control the password length and choose which character sets to include: uppercase letters, lowercase letters, numbers, and special symbols. Each generated password is unique and cryptographically secure.

What is entropy and why does it matter?

Entropy measures the randomness and unpredictability of a password. Higher entropy means a stronger password that is harder to crack. Our Password Generator calculates the entropy in bits for each generated password, so you can see at a glance how secure it is. A password with 80+ bits of entropy is generally considered strong enough for most purposes.

Can I customize the password length and character sets?

Yes. You can set any length from 4 to 128 characters and toggle each character type independently: uppercase, lowercase, numbers, and special characters. We recommend at least 12 characters with all character types enabled for maximum security.

What hashing algorithms are supported?

The Hash Generator supports four widely-used cryptographic hash algorithms: MD5 (128-bit), SHA-1 (160-bit), SHA-256 (256-bit), and SHA-512 (512-bit). SHA-256 and SHA-512 are the most recommended for modern applications.

What is hashing and when should I use it?

Hashing is a one-way mathematical process that converts input data of any size into a fixed-size string of characters called a digest. It is used for data integrity verification, file checksums, password storage, and digital signatures. Since hashing is irreversible, it is ideal for verifying data has not been tampered with.

Can I hash files or only text?

You can hash both text strings and files. Simply paste your text or drag and drop a file into the input area, select your preferred algorithm, and the hash will be generated instantly.

What is a JWT and why would I need to decode it?

A JSON Web Token (JWT) is an open standard (RFC 7519) for securely transmitting information as a JSON object. It is commonly used for authentication and authorization in web applications. Decoding a JWT lets you inspect its three parts: the header (algorithm), payload (claims/data), and signature (verification).

Does the JWT Decoder store my tokens?

No. The JWT Decoder processes tokens entirely in your browser. Tokens are never sent to any server, ensuring that sensitive authentication data remains private.

Can I decode expired or invalid JWTs?

Yes. The JWT Decoder will display the payload contents of any validly formatted JWT, regardless of whether it has expired or is invalid. It will also highlight expiration status and any signature verification issues to help you debug authentication problems.

What does the JSON Formatter & Validator do?

The JSON Formatter beautifies compact or minified JSON by adding proper indentation and line breaks for readability. It also validates JSON syntax, highlighting any errors such as missing commas, misplaced brackets, or invalid values so you can fix them quickly.

Can it also minify JSON?

Yes. You can toggle between formatting (beautify) and minifying modes. Minification removes all unnecessary whitespace and line breaks, producing the most compact JSON possible — ideal for production APIs and reducing bandwidth.

What size of JSON can it handle?

The tool handles JSON documents of practical sizes encountered in everyday development. For extremely large files (hundreds of megabytes), performance may vary depending on your browser and device. For most use cases, it performs excellently.

How does the JSON Compare tool work?

The JSON Compare tool takes two JSON inputs and performs a deep comparison, highlighting added, removed, and modified keys along with their values. Changes are color-coded for easy visual identification, making it simple to spot differences between two versions of a configuration file, API response, or data structure.

Does it handle nested JSON objects?

Yes. The comparison is recursive and handles arbitrarily nested objects and arrays. It accurately identifies differences at every level of nesting, so you won't miss changes buried deep within complex data structures.

What does the Regex Tester & Explainer do?

It runs your regular expression against your own text as you type, highlights every match in place, and lists each match with the text its capture groups picked up. Alongside that it breaks the pattern into pieces and describes each one in plain English, so you can see what a pattern does without deciphering it yourself. A replace view previews substitutions, and a cheat sheet inserts tokens straight into the pattern.

Which regular expression syntax does it use?

JavaScript's own. The pattern is compiled with the browser's regular expression engine and matched exactly as String.match and String.replace would, flags included — so what you see in the tester is what your JavaScript or TypeScript code will do. Syntax from other languages, such as possessive quantifiers or recursion, is not supported.

Can a slow regular expression freeze the page?

The tester stops scanning after 250 milliseconds or 500 matches and tells you it did, so a runaway pattern cannot lock up the tab. It also warns you when a pattern repeats a group that already repeats inside — the shape behind catastrophic backtracking, which is worth fixing before that pattern reaches production.

What is Base64 encoding and when is it used?

Base64 is an encoding scheme that converts binary data into an ASCII string format. It is commonly used to embed images in HTML, encode data in URLs, attach files to emails (MIME), and transmit binary data over text-based protocols.

Can I encode images with the Base64 tool?

Yes. You can paste text or upload an image file (PNG, JPG, GIF, SVG, etc.) to encode it as a Base64 string. The decoded output can then be used in HTML img tags, CSS backgrounds, or any context that accepts Base64-encoded data URIs.

What is the maximum file size I can encode?

The tool handles files of practical sizes encountered in everyday development. Very large files (over 50 MB) may impact browser performance depending on your device. For most use cases, it works smoothly with files up to tens of megabytes.

What does URL encoding do?

URL encoding (also known as percent-encoding) converts characters that are not allowed in URLs into a safe format using percent signs followed by hexadecimal digits. For example, spaces become %20, ampersands become %26, and special characters are encoded to ensure URLs are valid and safe to transmit.

Can it encode query parameters?

Yes. The tool can encode and decode individual query parameters or entire URLs. Use it to safely embed special characters in URL query strings, form data, or API endpoints.

What is a Unix timestamp?

A Unix timestamp (also called epoch time) is the number of seconds (or milliseconds) that have elapsed since January 1, 1970, 00:00:00 UTC (excluding leap seconds). It is the standard way to represent time in many programming languages and systems.

Can I convert between seconds and milliseconds?

Yes. The converter handles both seconds and milliseconds timestamps. You can specify which unit your input is in, and the tool will display the equivalent human-readable date and time in your local timezone, as well as UTC.

Does it support different timezones?

The converter displays the converted date and time in your browser's local timezone by default. It also shows the equivalent UTC time. You can use the current time button to quickly insert the present Unix timestamp.

How does the CSV to JSON conversion work?

The converter reads the first row of your CSV data as column headers (keys) and converts each subsequent row into a JSON object using those headers. It handles standard CSV formatting including comma delimiters, quoted fields, and escaped characters.

Can it handle CSV files with special characters?

Yes. The converter properly handles quoted fields containing commas, line breaks, and special characters. It follows standard CSV parsing rules as defined by RFC 4180, ensuring accurate conversion even with complex data.

What delimiter options are available?

The default delimiter is a comma, but you can also use semicolons, tabs, pipes, or custom delimiters. This flexibility allows you to work with various CSV formats encountered in different systems and exports.

What is a UUID and why is it useful?

A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit value designed to be unique across both space and time. UUIDs are widely used in databases, distributed systems, file naming, and API design to ensure unique identifiers without centralized coordination.

Which UUID version does OkTools generate?

OkTools generates UUIDs using Version 4 (random), which produces identifiers using cryptographically secure random numbers. This is the most widely used UUID version and provides an extremely low probability of collision — approximately 1 in 2¹²².

Can I generate multiple UUIDs at once?

Yes. You can specify how many UUIDs to generate in a single batch. This is useful for testing, seeding databases, or creating multiple unique identifiers quickly. Each UUID is independently random and collision-free.

What is Lorem Ipsum used for?

Lorem Ipsum is placeholder text used in the design and publishing industries to fill layouts before final content is ready. It allows designers and developers to focus on visual design, typography, and layout without being distracted by readable content.

Can I control how much text is generated?

Yes. You can specify the number of paragraphs, sentences, or words to generate. This gives you precise control over the amount of placeholder text, whether you need a short snippet for a small UI element or extensive content for a full-page layout mockup.

What is the Credit Card Number Generator for?

The Credit Card Number Generator creates test card numbers that pass the Luhn algorithm validation check. These are not real, active credit cards — they are purely for testing payment forms, validation logic, and checkout flows in development and QA environments.

Which card brands are supported?

The generator produces test numbers formatted to match the patterns of major card brands including Visa, Mastercard, American Express, and Discover. Each generated number passes the Luhn check and follows the issuing identification number (IIN) ranges for the selected brand.

Can I use these numbers for real purchases?

No. These are test numbers only and cannot be used for any real transactions. They are designed exclusively for development testing, form validation, and QA purposes. Never use generated test numbers in production environments.

What is the SSN Generator for?

The SSN Generator creates realistic fake Social Security Numbers along with names and dates of birth for testing and development purposes. These are not real SSNs — they follow the US format (XXX-XX-XXXX) with randomly generated area, group, and serial numbers, paired with plausible names and dates.

Which countries are supported?

The generator currently supports names from six countries: United States, United Kingdom, Germany, France, Canada, and Australia. While the SSN format is US-specific, the tool generates culturally appropriate names for each selected country alongside valid-format US Social Security Numbers.

Can I use these SSNs for real transactions?

No. These are randomly generated numbers that follow the US SSN format but are not assigned to any real individuals. They are designed exclusively for development testing, form validation, and QA purposes. Never use generated test SSNs in production environments or for any real identification purposes.