Developer Tools
Format JSON, generate UUIDs, test regex, hash strings, encode Base64 and URLs. Every tool runs entirely in your browser. Open DevTools → Network and watch: nothing leaves your tab.
Built for daily developer workflows
Fifteen tools for JSON, YAML and XML, cron, CSV, timestamps, hashing, HMAC signing, regex, encoding and ID generation. Pages target Lighthouse 100 on mobile and load in under 100ms TTI.
Pick a tool below or jump straight to JSON Formatter if that's why you came.
Cron Expression Parser
Explain any cron expression in plain English and preview the next 5 run times. Inline cheatsheet.
Unix Timestamp Converter
Convert epoch ↔ date, seconds or milliseconds, ISO 8601, UTC and any timezone. Batch convert.
CSV Viewer & Formatter
View CSV as a sortable table, auto-detect the delimiter, export to JSON or TSV. Nothing uploaded.
JSON Formatter & Validator
Format, validate, and minify JSON with syntax highlighting and tree view.
Markdown Preview
Write and preview Markdown in real-time. Side-by-side editor with live rendering.
Diff Checker
Compare two texts side by side or inline, with word-level highlighting.
XML Formatter
Format, minify and validate XML with the browser's native parser. Mixed content safe.
SQL Formatter
Beautify or minify SQL with dialect, indentation and keyword-case options.
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-384, SHA-512 hashes from any text or file. Hex or Base64 (SRI ready).
UUID Generator
Generate UUID v4 instantly. Bulk generate, copy with one click.
Regex Tester
Test regular expressions with live matching, pattern explainer (token-by-token), and replace.
URL Encoder / Decoder
Encode or decode URLs and query strings. Handles Unicode and percent-encoding.
Base64 Encoder / Decoder
Encode or decode Base64 strings instantly. Supports text and file input.
HMAC Generator
Sign payloads with HMAC-SHA-256 / SHA-512 (and MD5/SHA-1 for legacy). Stripe, GitHub, Slack, Twilio webhooks & JWT.
YAML Formatter & Validator
Format, validate, and minify YAML 1.1 and 1.2. Error line/column on invalid input. Runs locally.
Frequently Asked Questions
Why no built-in API or CLI to use these tools programmatically?
These tools are 100% client-side and designed for interactive use. A public API (api.praticulus.com/v1) and an npm CLI (@praticulus/cli) are planned for automated workflows. See Coming next.
Can these tools handle very large inputs (10MB+ JSON)?
Yes, within the limits of your browser's RAM. Around 100 MB JSON parsing remains smooth on a modern device. No application-side hard limit on Praticulus.
Are the regex, JSON and Base64 engines spec-compliant?
They use native browser APIs (JSON.parse, ECMAScript RegExp, atob/btoa, Web Crypto API for hashes, and DOMParser for XML). Behavior is identical to what your production JS runtime will produce.
Can I share a formatted result with a teammate via URL?
On some tools, yes. The XML Formatter and Regex Tester encode their state in the URL hash; URL sharing is being extended across the other tools. See tool-engagement-url-state in the roadmap.
Where can I see the source code of the tools?
The full source is public at github.com/jamalofski/praticulus (MIT). You can also use View Source in your browser: all logic is inline.