LocalBench
Local-first developer utilities, 100% client-side
Developer utilities that don't phone home
LocalBench is a small set of everyday tools — formatting JSON, diffing text, beautifying SQL, converting between case styles, Unix timestamps, and color formats, encoding and decoding Base64 and URLs, decoding, verifying, and generating JWTs, generating and verifying MD5/SHA checksums, generating UUIDs, ULIDs, and QR codes, testing regular expressions, explaining cron expressions, calculating IPv4 subnets, diffing JSON structurally rather than line by line, formatting and validating XML — built to run entirely as client-side JavaScript. No upload step, no account, no server round trip. Paste something in and the result appears instantly, even offline. There's also a searchable directory of AI developer tools and a plain-English HTTP status code reference for when you need to find or look something up rather than compute it.
JSON Formatter
Validate, format, and explore JSON
Text Differ
Compare two blocks of text line by line
SQL Beautifier
Reformat unruly SQL into readable queries
Base64 Encoder
Encode text or a file to Base64
Base64 Decoder
Decode Base64 to text, an image, or a file
JWT Debugger
Decode, inspect, and verify JSON Web Tokens
JWT Generator
Build and sign a test JSON Web Token
URL Encoder
Percent-encode text or a full URL
URL Decoder
Decode a percent-encoded URL back to plain text
XML Formatter
Format, minify, and validate XML
Case Converter
Convert identifiers between camelCase, snake_case, kebab-case, and more
Timestamp Converter
Convert between Unix epoch time and human-readable dates
QR Code Generator
Generate QR codes with a logo, for text, URLs, Wi-Fi, and contact cards
JSON Diff
Compare two JSON documents field by field, not line by line
Color Converter
Convert between HEX, RGB, HSL, and OKLCH, plus a WCAG contrast checker
Hash Generator
Generate and verify MD5/SHA checksums for text or files
UUID / ULID Generator
Generate random UUID v4s or sortable ULIDs, in bulk
RegEx Sandbox
Test regex patterns and see them explained plain-English
CIDR / Subnet Calculator
Calculate network/broadcast addresses, host range, and mask from a CIDR block
HTTP Status Code Reference
Search every HTTP status code with a plain-English explanation
AI Tools Directory
Search a curated directory of developer-focused AI tools
Cron Explainer
Decode a cron expression into plain English and upcoming run times
Why local-only processing?
API responses, database queries, and internal config often carry data you shouldn't paste into a third-party server. Every tool here runs as plain JavaScript in your tab — there's no backend to send your input to, so it's safe to use on real, sensitive data.