Free Developer Tools | Toolivaro

Popular tools

JSON Formatter & Validator Stable Format and validate JSON with readable indentation, precise error messages, and byte-size stats — fully local.

JSON Minifier Stable Compress JSON to its smallest valid form — strip all whitespace, count the bytes saved, and copy or download.

CSV to JSON Converter Stable Convert CSV files and pasted tables into JSON objects with automatic delimiter detection and header mapping.

JSON to CSV Converter Stable Convert a JSON array of objects into RFC 4180 CSV with correct quoting, column union, and copy or download.

Base64 Encoder & Decoder Stable Encode text or files to Base64 and decode back, with UTF-8 handling, validation, and size stats — fully local.

AI Token Counter Stable Estimate tokens and API cost for any prompt across GPT-4o, Claude Sonnet 4, and other models — fully local.

Regex Tester Stable Test regular expressions live against your own text with match highlighting, capture groups, and flags — fully local.

Text Diff Checker Stable Compare two blocks of text line by line with added, removed, and unchanged highlighting plus change statistics — fully local.

Unix Timestamp Converter Stable Convert between Unix seconds, Unix milliseconds, ISO 8601, and human-readable local time — live, fully local.

UUID Generator Stable Generate RFC 4122 version-4 UUIDs from cryptographically secure randomness — one at a time or in bulk, fully local.

URL Encoder / Decoder Stable Encode or decode text for safe use in URLs with percent-encoding — instant, fully local, and faithful to the browser.

Hex to RGB Converter Stable Convert hex color codes to RGB triplets and back — instantly, with 3- and 6-digit shorthand support, fully local.

Number Base Converter Stable Convert integers between binary, octal, decimal, and hexadecimal with exact BigInt arithmetic — no rounding, fully local.

Data Size Converter Stable Convert between bits and bytes — KB, MB, GB, TB, PB — with decimal (SI) precision, exact arithmetic, fully local.

Password Generator Stable Generate strong passwords locally with cryptographically secure randomness — unbiased sampling, class guarantees, zero uploads.

Hash Generator Stable Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes locally with WebCrypto — hex and base64 output, nothing uploaded.

JWT Decoder Stable Decode JWT header, payload, and claims locally — with optional HMAC signature verification. Nothing leaves your browser.

Cron Builder Stable Build and validate five-field cron expressions with a human-readable description and honest next-run times.

About this category

Developer Tools on Toolivaro follow the same standard as every other page on the site: each tool shows its formula or method, its assumptions, a worked example, and its limitations, and every result is computed locally in your browser.

All tools are reviewed on a regular schedule. If a calculation looks wrong to you, use the correction link at the bottom of the tool page — corrections are reviewed by a human and the reviewed date is updated when changes land.

Other categories

Business Calculators Profit margin, markup, break-even, and cash runway calculators that help you make fast, accurate business decisions. Math Calculators & Converters Percentage calculations and unit conversions for everyday math — computed locally in your browser with explicit formulas and exact conversion factors. Health Calculators Body-mass-index and health calculations with authoritative sources, clearly stated assumptions, and results that stay on your device. Home & Construction Estimators Paint, flooring, tile, concrete, and gravel estimators with metric and imperial units, waste allowances, and package counts. Time & Date Tools Date differences, business days, time-zone conversions, and meeting-overlap planning with correct daylight-saving handling. Image Tools Resize, compress, and convert JPG, PNG, and WebP images privately — processing happens locally, and your files are never uploaded. All tools Browse the complete Toolivaro catalog.