All Tools
41 free developer tools. All run locally in your browser for maximum privacy and speed.
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API Tools(7)
API Key Checker
Validate your AI API keys instantly
API Key Bulk Checker
Validate multiple API keys in one run
API Key Check History
Track key validation results in your browser
API Health Monitor
Monitor API endpoints with uptime checks, latency history, and Slack/email alerts.
OpenAI Key Checker
Validate OpenAI API keys and inspect model access instantly
JWT Decoder
Decode and verify JWT tokens
Webhook Tester
Generate, inspect, and verify webhook signatures locally
JSON Tools(3)
Developer(17)
Markdown Editor
Write, preview, and export Markdown with live rendering
Regex Tester
Test regex patterns with live matches and groups
Git Commit Generator
Paste a git diff and generate clean conventional commit messages instantly
Email Validator
Validate email addresses, inspect domains, and generate mailto links
URL Parser
Break URLs into parts and query parameters
Cron Builder
Build cron expressions with presets and human-readable output
Cron Job Monitor
Monitor scheduled tasks with heartbeat URLs, live status, and ping history.
Lorem Ipsum Generator
Generate placeholder text in Classic, Hipster, Pirate, and Dev flavors. Paragraphs, sentences, or words with HTML and Markdown export.
Unix Timestamp Converter
Convert Unix epoch timestamps to readable dates and back. Live clock, timezone support, seconds and milliseconds auto-detection.
HTML Entities Encoder/Decoder
Encode and decode HTML entities with named, decimal, and hex modes.
Uptime Monitor
Ping any URL and monitor availability, response time, and HTTP status. Auto-refresh with configurable intervals.
SSL Certificate Checker
Check SSL/TLS certificate expiry, issuer, cipher suite, and SANs for any domain. Instant results — no signup required.
QR Code Generator
Generate QR codes from any URL, text, email, phone, or Wi-Fi credentials. Download as PNG or SVG. 100% in-browser.
Color Picker
Pick any color and instantly get HEX, RGB, HSL values. Use the EyeDropper to sample any pixel on screen.
UUID Generator
Generate UUID v4 (random), v7 (time-sorted), v5 (namespace), and GUIDs. Bulk generate up to 500, decode & validate.
Word Counter
Count words, characters, sentences, paragraphs and estimate reading time. Paste any text and get instant statistics.
URL Encoder / Decoder
Encode and decode URL components with percent-encoding. Handles spaces, special characters, and Unicode. Instant, client-side.
Business(3)
VAT Calculator
Calculate VAT from net or gross amounts with instant tax breakdown
MCL Calculator
Calculate markup, cost, and list price with margin insights
Polymarket Calculator
Calculate Polymarket position P&L, ROI, break-even, and payout scenarios
SEO(4)
Meta Tags Previewer
Preview Open Graph and Twitter meta tags before sharing
PageSpeed Score
Run Google Lighthouse checks with Core Web Vitals and category scores
Sitemap Checker
Fetch and validate any sitemap.xml — count URLs, detect sitemap index, inspect lastmod and priority values. Works with sitemap indexes.
Robots.txt Tester
Fetch and parse any robots.txt file. View crawl directives per user-agent and test whether a specific URL path is allowed or blocked.
AI Tools(3)
AI Token Counter
Count tokens and estimate API costs for GPT-4, Claude, Gemini and more
Prompt Tokenizer
Estimate token count and API cost for any prompt across GPT-4.1, Claude 3.7, Gemini 2.5 and more. Adjust expected output tokens to calculate total cost.
AI Model Cost Calculator
Compare API costs across all major LLMs — GPT-4o, Claude, Gemini, Llama. Enter token counts and monthly request volume to find the cheapest option.
Security(3)
Password Generator
Generate strong, secure random passwords. Customize length, character sets, create passphrases. 100% client-side.
Human-Friendly Password
Generate memorable, pronounceable passwords. Syllable-based, word patterns, PIN codes. Secure via crypto.getRandomValues().
Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes from any text. 100% client-side using Web Crypto API.