Math & Numbers

Step-by-step factor-label unit cancellation with inverted-factor diagnosis and optional student-answer checking.

Finance

Compare four depreciation methods side by side: straight-line, declining balance (with multiplier, e.g. 2 for DDB), sum-of-the-years'-digits (SYD), and units of production (when yearly usage is provided). Shows book-value curves and a year-by-year depreciation table.

Network

Build RFC 1035 DNS zone files (SOA + NS/A/AAAA/CNAME/MX/TXT/SRV/CAA/TLSA/NAPTR/DS) with per-record validation and a readable summary.

Development

Check email HTML templates for cross-client compatibility: unsupported CSS, non-inline styles, Outlook traps, table layout issues, and accessibility gaps.

Math & Numbers

Compute observed frequency and frequency shift for a moving source and/or observer

Math & Numbers

Compute density, mass, or volume from the other two, with specific gravity and a float/sink check

Design

Extract design tokens — colors, numbers, font sizes and strings — from an ECharts theme JSON and export them straight into your design system. Paste a theme object (the kind registered via echarts.init(dom, themeName)) and the tool walks every leaf, tagging each color (with optional named/rgb → hex normalization), spacing number, font size and string, then emits clean CSS variables, a Tailwind theme.extend config, Style Dictionary tokens.json, or SCSS variables. Bridges the gap between an ECharts visualization theme and Figma/CSS/Tailwind design tokens without copying each value by hand.

Security

Paste a .env file and get a staged secret-rotation plan. Detects database URLs, API keys, auth tokens, private keys, cloud credentials, payment keys and encryption secrets, scores each by exposure and age, and schedules them across a 4-week rotation timeline with a dual-key checklist and a generated .env.example. Optional last-rotated dates and a configurable cadence (30/90/180/365 days) drive compliance scoring.

Math & Numbers

Calculate reaction velocity with Michaelis-Menten, estimate Km/Vmax via Lineweaver-Burk, and model enzyme inhibition.

Security

Sign a message with a private key or verify a signature with a public key — supports RSA-PSS (SHA-256), ECDSA (P-256), and Ed25519. Pure client-side crypto (Node crypto.createSign/createVerify), no network. Paste a PEM key to sign or to verify a base64 signature. This tool signs/verifies; it does not generate key pairs.

Security

Measure the randomness of any data — Shannon entropy (bits/symbol), Min-Entropy (worst-case guess work), alphabet size, duplicate rate, and an average brute-force cracking time at a chosen hash rate. Rates data as Strong (≥128-bit min-entropy), Medium (64-127), or Weak (<64).

Text Processing

Convert AI-typical plain ASCII into proper typography: -- and --- become en/em dashes, straight quotes become curly/smart quotes (locale-aware), ... becomes a single ellipsis …, spaced dashes are tightened, and repeated spaces collapse — while fenced ``` code blocks and `inline` code are left untouched.