Interactive micro-tools for humans and AI agents
mcp.gholl.com is a hub of free, login-free micro-tools. Use the interactive cards in your browser, or connect any MCP-capable AI client to the Model Context Protocol endpoint and let your agent call them.
Connect via MCP
Endpoint: https://mcp.gholl.com/mcp · Discovery: /.well-known/mcp.json · Agent index: /llms.txt
{
"mcpServers": {
"gholl": {
"type": "http",
"url": "https://mcp.gholl.com/mcp"
}
}
}
51 tools
GPU VRAM & Deployment Estimator
Estimate the VRAM required to serve an LLM and get GPU recommendations with ready-to-copy vLLM / Ollama commands.
Cron & Regex Debugger
Translate a cron schedule into plain language, preview the next runs, and test regular expressions with live highlighting.
JSON-LD / Schema Viewer
Inspect, validate and explore structured JSON / JSON-LD with a collapsible tree, syntax checks and JSON-LD detection.
API Health & Latency
Probe an API endpoint, measure live latency, and view a 24h uptime and latency dashboard.
BaZi Chrono-Energy Wheel
Compute the Four Pillars (BaZi) from a birth date/time and explore the five-element energy wheel and luck cycles.
JWT Decoder
Decode a JWT into its header, payload and claims, and check whether it is expired.
Hash Generator
Compute SHA-1 / SHA-256 / SHA-512 digests of text as hex and base64, entirely in your browser.
Color Studio & Contrast
Convert between hex/RGB/HSL, generate tints and shades, and check WCAG contrast against black and white.
Gomoku · Play vs AI
Play Gomoku (five-in-a-row) against your host AI. The card provides the board, move rules and win detection.
ECharts Data Visualization
Render interactive Apache ECharts charts from an ECharts option — line, bar, pie, radar, scatter, sankey and more.
Function Grapher
Plot common functions with live parameter sliders (linear, inverse, quadratic, power, exponential, logarithmic) and read off key features.
Trigonometry Lab
Explore the unit circle and trigonometric functions y = A·sin(ωx+φ)+k with live sliders for amplitude, period and phase.
Geometry Lab
Drag triangles, quadrilaterals and circles to explore sides, angles, area and the Pythagorean / sine / cosine theorems.
Conic Sections
Plot circles, ellipses, parabolas and hyperbolas with live sliders, showing foci, eccentricity and asymptotes.
JSON Formatter
Validate, pretty-print, minify and sort JSON keys, with byte/line/node stats.
Unit Converter
Convert length, mass, area, volume, temperature, speed, data and time units.
CSS Gradient Generator
Design a CSS gradient with a live preview and copy-ready code.
CSS Box Shadow
Build a CSS box-shadow with a live preview.
CSS Border Radius
Shape CSS corners with a live preview.
BMI Calculator
Body-mass index with a colored scale.
HTTP Status Codes
Color-coded reference for HTTP status codes.
Dice Roller
Roll cryptographically-random dice and read the total.
World Clock
Live times across major cities with a day/night indicator.
Coin Flip
Fair coin flip using the Web Crypto API.
Tip & Bill Split
Add a tip and split a bill with a visual breakdown.
Statistics
Mean, median, standard deviation and a histogram for a data set.
Prime Factorization
Prime factorization, divisors and primality.
Color Palette
Generate a harmonious palette from a base color.
Bit Visualizer
See an integer as a grid of bits, with binary/octal/hex.
Matrix Calculator
Multiply, transpose and take determinants of matrices.
Amount in Chinese
Render an amount in Chinese capital numerals, like a receipt.
Color Blindness Simulator
Preview a color under different color-vision deficiencies.
Random Picker
Spin a wheel to fairly pick from a list.
QR Code Generator
Generate a QR code from text or a URL.
Loan Calculator
Monthly payment, total interest and a balance chart.
Compound Interest
Project compound growth over time.
Password Strength
Estimate password strength and entropy.
Resistor Color Code
Decode a 4-band resistor into ohms.
JSON to Table
Render JSON as a readable table.
Text Diff
Line-by-line diff between two texts.
Reaction Test
Interactive reaction-time measurement.
Typing Test
Measure typing speed and accuracy.
Markdown Preview
Write Markdown and preview it rendered.
CSV to Chart
Chart a CSV instantly (bar or line).
TOTP Generator
Generate time-based one-time codes (2FA).
Image to Base64
Convert an image to a data URI / Base64.
Image Compressor
Compress an image in the browser.
Favicon Generator
Turn text or an emoji into a favicon.
DNS Lookup
Resolve DNS records over DNS-over-HTTPS.
HTTP Inspector
Fetch a URL and inspect status, redirects and headers.
Quiz
A universal quiz card. The AI defines the questions, the options, each option’s score and how many to show per page; the card renders them and reports the answers back.