JSON Formatter
Format, validate, and prettify JSON. Error detection with line numbers.
Open toolFocused tools with practical guidance
Privacy-friendly developer tools for safer everyday workflows.
Fast browser utilities for JSON, Base64, JWT, Regex, Hash, URL encoding, timestamps, text diff, Markdown preview, and strong passwords — paired with examples, caveats, and local-first guidance.
12 focused tools16 concept guides0 signup stepsLocal-first processing notes
local workflow console
01
Inspect
Debug API payloads
Format JSON, decode Base64, inspect JWT claims, and convert timestamps without losing the security context.
02
Validate
Prepare safe strings
Encode URL components, test regular expressions, and generate hashes with visible edge-case notes.
03
Protect
Create strong credentials
Generate high-entropy passwords with clear reminders about managers, reuse, and shared devices.
Boundary first: avoid pasting production secrets, private keys, customer records, or regulated data into any online page.
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Open and save core tools to build a small local workspace. Favorites and recent tools are stored only in this browser.
Manage workspaceFeatured tools
Focused developer utilities
Each featured page includes examples, caveats, and data-handling notes.
Base64 Encode/Decode
Encode text to Base64 or decode back. UTF-8 support.
Open toolTimestamp Converter
Convert Unix timestamps to dates and vice versa.
Open toolJWT Decoder
Decode JSON Web Tokens to view header and payload.
Open toolRegex Tester
Test regular expressions with flags. See all matches.
Open toolHash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes.
Open toolURL Encoder/Decoder
Encode or decode URL components safely.
Open toolPassword Generator
Generate strong passwords. Custom length and characters.
Open toolText Diff Checker
Compare two texts side by side. See what changed.
Open toolMarkdown Preview
Write Markdown and see live preview. GitHub-flavored.
Open toolCSS Formatter
Format or minify CSS code. Beautify messy stylesheets instantly.
Open toolUUID Generator
Generate random UUIDs (v4). Batch generate multiple at once.
Open toolInspect
Debug API payloads
Format JSON, decode Base64, inspect JWT claims, and convert timestamps without losing the security context.
Open workflow →Validate
Prepare safe strings
Encode URL components, test regular expressions, and generate hashes with visible edge-case notes.
Open workflow →Protect
Create strong credentials
Generate high-entropy passwords with clear reminders about managers, reuse, and shared devices.
Open workflow →Guides
Concepts before copy-paste
Practical articles explain what the tools can do, what they cannot prove, and how to avoid common developer mistakes.
7 min read
Base64 is not encryption
A practical guide explaining what Base64 encoding does, why it is reversible, where it is useful, and why it should not be used to protect secrets.
8 min readJWT decode vs verify
A developer guide to decoding JWT header and payload fields, verifying signatures, reading exp and iat claims, and avoiding common token mistakes.
8 min readURL encoding for query parameters
Learn when to encode a query parameter, how percent encoding works, why double encoding breaks links, and how to debug malformed escape sequences.
9 min readHashing vs encryption
A practical comparison of hashing, encryption, checksums, password hashing, and when SHA-256, MD5, bcrypt, scrypt, or Argon2 fit the job.
7 min readBase64URL vs Base64
A practical guide to the URL-safe Base64 alphabet, padding, JWT segments, and why ordinary Base64 can break inside URLs and filenames.
8 min readUTF-8 and percent encoding
Understand how Unicode text becomes UTF-8 bytes, how percent encoding represents those bytes in URLs, and why copied links sometimes look unreadable.
8 min readencodeURI vs encodeURIComponent
A practical guide for choosing between JavaScript encodeURI and encodeURIComponent when building links, query strings, callbacks, and nested URLs.
8 min readWhy MD5 and SHA-1 are legacy
Understand why MD5 and SHA-1 still appear in old checksums, why they are unsuitable for new trust decisions, and when SHA-256 or stronger options are better defaults.
8 min readHow to choose password length
A practical guide to choosing password length, understanding entropy estimates, using passphrases, and avoiding common password generator mistakes.
8 min readHow to read JSON parse errors
Learn how to interpret common JSON parse errors, spot trailing commas, quote problems, control characters, and malformed nested data from APIs or logs.
7 min readSeconds vs milliseconds
A guide to recognizing Unix timestamp units, converting UTC and local time correctly, and avoiding common API, log, and JWT time mistakes.
8 min readRegex greedy vs lazy
A practical JavaScript regex guide to greedy and lazy quantifiers, capture groups, replacement previews, and safer matching against real sample text.
8 min readText diff review workflows
A practical guide to comparing documentation, configuration, release notes, and copied snippets without turning every small change into a noisy review.
8 min readSafe Markdown preview workflow
A practical guide to previewing Markdown structure, links, tables, code blocks, and task lists before publishing documentation or support content.
8 min readCSS formatting review workflow
A practical workflow for formatting CSS, reviewing selector inventory, checking cascade risks, and deciding when project-level linters are still required.
8 min readUUID v4 test identifiers
Learn when UUID v4 identifiers are useful for test data, fixtures, API examples, and mock records—and why IDs are not permissions or secrets.