Generate a unique URL to easily test, receive and inspect HTTP webhooks in real-time. View request headers, query parameters, JSON payloads, and more.
Estimate token count for GPT-5, Claude 3, Gemini, and Llama models. Paste any text to see token usage and estimated API cost instantly.
Test and validate API keys for OpenAI, Anthropic, Google AI, and other services. Secure validation without storing keys on our servers.
Calculate monthly payments, interest cost, origination fees, and payoff savings for a business loan with optional extra monthly payments.
Find the nearest Tailwind CSS color class for any hex, rgb(), or hsl() color. Matches against the full Tailwind v3 palette and shows the top 12 closest colors with swatches and class names.
Calculate compound interest on savings and investments. See how your money grows over time with monthly or yearly compounding and regular contributions.
CORS tester checks whether a URL allows cross-origin requests from your browser, and explains exactly why a request was blocked when it fails. Free, no signup.
Look up detailed information about any country - capital, population, area, languages, currencies, timezones, and flag. Powered by the REST Countries API.
Parse cron expressions into plain English descriptions, field breakdowns, and validation feedback without making any server request.
Check live cryptocurrency prices for the top 500 coins by market cap. Displays real-time price, 24h change, market cap, and trading volume via the free CoinGecko API. Export data as JSON for developer workflows.
CSR decoder reads the subject, public key algorithm and size, and requested SANs from a PEM certificate signing request, and verifies its self-signature. Free, no signup.
Build cURL commands with method, headers, query params, auth, and body. Generate copy-ready shell requests for APIs and debugging.
Convert curl commands to JavaScript fetch, Axios, or Python requests code instantly. Paste your curl command and get clean, ready-to-run code.
Generate docker-compose.yml files with multiple services, ports, environment variables, volumes, and named networks. Supports build contexts, depends_on, and restart policies.
Build docker run commands with port mappings, volume mounts, environment variables, restart policies, and resource limits. Generates multi-line shell commands ready to copy. Free, browser-based.
Calculate exponential backoff retry schedules for API calls. Set base delay, multiplier, and max cap to see per-attempt delays with full, equal, or no jitter. Free online tool.
Scan a website for favicon, apple-touch-icon, and manifest icon coverage. Validate icon URLs, status codes, and recommended sizes.
Fetch GitHub repository metrics like stars, forks, open issues, and size using the public GitHub API. Quickly audit any repo without leaving your browser.
Fetch public GitHub profile metrics including followers, repos, and gists via the GitHub API - instant results, no login required.
Format GraphQL queries, mutations, subscriptions, and fragments or minify GraphQL documents for compact API and frontend code usage.
GraphQL to TypeScript converter turns GraphQL SDL types, enums, interfaces, and unions into ready-to-use TS interfaces. Free, instant, browser-based.
HAR file analyzer parses Chrome and Firefox DevTools exports into a readable performance report with request timing, sizes, and failures. Free, browser-based, no upload.
HAR to cURL converter turns a Chrome or Firefox DevTools HAR export into copy-ready curl commands for every captured request. Free, browser-based, private.
Parse raw HTTP request or response headers into a readable table, JSON structure, and quick audit view for security, caching, and CORS.
HTTP request to cURL converter turns a raw request from devtools, a proxy, or an .http file into a runnable curl command with correct shell quoting. Free, in your browser.
Inspect all HTTP response headers of any website. Audits security headers like HSTS, CSP, and X-Frame-Options and groups headers by type.
Check HTTP status codes, response headers, and redirect chains for any URL. Identify 301/302 redirects, 404 errors, and server response times instantly. Free, no signup required.
Look up any HTTP status code and its meaning instantly, from 200 OK and 404 Not Found to 500 Server Error. Browse or search the list free, no signup required.
Test if any website supports HTTP/2 and HTTP/3 (QUIC) via real TLS ALPN negotiation. Shows TLS version, server headers, alt-svc advertisement, and response time.
Flatten nested JSON objects into dot-notation keys instantly. Great for logs, spreadsheets, API payload inspection, and analytics workflows.
Convert JSON samples into GraphQL SDL type definitions with inferred scalars, nested object types, list fields, and non-null options.
Convert JSON data to JavaScript objects with proper formatting, key quoting options, and ES6 syntax output. Useful for pasting API responses directly into JS or TS files. Free, privacy-first.
Convert JSON data to Swift structs with Codable conformance. Generate type-safe Swift models from any JSON API response instantly.
Convert JSON data to TypeScript interfaces and types automatically. Generate strongly-typed interfaces from your JSON API responses.
Convert JSON samples into TypeScript-ready Zod schemas for runtime validation, API parsing, forms, and full-stack TypeScript projects.
Convert flattened dot-notation JSON keys back into nested JSON structure. Rebuild complex objects from flat API or CSV-style key maps.
Convert JWK to PEM and PEM to JWK for RSA and EC keys instantly in your browser using the Web Crypto API. No signup, keys never leave your device. Free online JWK PEM converter.
Latency percentile calculator turns raw response time samples into p50, p95, p99 and p99.9 with mean and standard deviation. Runs in your browser, free, no signup.
LLM token cost calculator estimates API spend per call, day, month and year across OpenAI and Claude models, with prompt caching and batch discounts. Free, no signup.
Calculate Equated Monthly Installments (EMI) for home loans, car loans, personal loans, and education loans. View amortization schedule with principal vs interest breakdown.
Convert Markdown to reStructuredText (RST) instantly online. Perfect for Python Sphinx docs, ReadTheDocs, and PyPI package README files. Free, browser-based, no signup.
Calculate monthly mortgage payments, total interest, and view a full amortization schedule. Supports fixed-rate loans with customizable down payment, interest rate, and loan terms.
Analyze nginx and Apache access logs online. See top IPs, endpoints, status codes, and user agents with visual charts. Paste log lines directly - no upload or server access needed.
Check daily, weekly, or monthly NPM download counts for any package using the official registry API. Compare trends and gauge library adoption instantly.
Look up npm package metadata, versions, dependencies, and maintainers instantly using the official NPM registry API - no login needed.
OpenAPI diff checker compares two Swagger or OpenAPI specs and flags breaking changes: removed paths, methods, and newly required parameters. Free, browser-based.
Convert OpenAPI 3.x and Swagger 2.x JSON specs to readable Markdown API documentation. Extracts endpoints, parameters, and responses. Free, browser-based.
OpenAPI to Postman collection converter turns OpenAPI 3.x or Swagger 2.x specs into a ready-to-import Postman v2.1 JSON file with params and bodies. Free, browser-based.
OpenAPI to TypeScript converter generates interfaces, unions and request or response types from any OpenAPI 3.x or Swagger 2.0 spec. Free, no signup, browser based.
View and interact with Swagger/OpenAPI specifications from a URL or pasted JSON. Explore endpoints, schemas, and try API calls directly in the browser.
PII redactor strips emails, IPs, card numbers, API keys, and tokens out of logs and text before you share them. Free, runs locally, nothing is uploaded.
Test HTTP latency to a public website with repeated ping attempts, average response time, jitter, and request-failure tracking.
Generate OAuth 2.0 PKCE code verifiers and S256 code challenges instantly using the Web Crypto API. Build a ready-to-use authorization URL. Free, runs entirely in your browser.
Search and discover 1,400+ free public APIs across 50+ categories. Filter by authentication type, CORS support, and HTTPS to find the perfect API for your next project.
Inspect Python package metadata, release version, classifiers, and compatibility details directly from the PyPI JSON API. Useful for auditing Python dependencies.
Generate up to 5000 realistic fake user profiles for API testing and development. Customise payload fields - name, email, phone, address, avatar, login, DOB - and export as JSON using the randomuser.me API.
Analyze API rate limit headers instantly to see remaining quota, reset countdown, and usage percentage. Supports X-RateLimit, RateLimit, and Retry-After.
Trace the full redirect chain for any URL. See every HTTP hop, status code, and final destination to debug SEO, link shorteners, and site migrations.
Calculates a week-by-week calorie increase schedule to safely restore your metabolism after dieting or fasting, preventing fat regain while returning to maintenance calories.
Pick any color from your screen using the browser's native EyeDropper API. Get HEX, RGB, and HSL values instantly. Build and export color palettes as CSS variables.
Calculate the best bedtime or wake-up time based on 90-minute sleep cycles. Find out when to sleep or wake up to feel fully rested and avoid grogginess.
Real-time character counter for Twitter/X, Instagram, LinkedIn, TikTok, Threads, Pinterest, and YouTube with platform-specific limits.
Generate RSA (2048/4096-bit) and ECDSA (P-256/P-384) SSH key pairs entirely in your browser using the Web Crypto API. Your private key never leaves your device.
Generate systemd .service unit files for Linux. Configure service name, user, exec command, restart policy, and environment variables. Free, runs entirely in your browser.
Generate ULIDs, lexicographically sortable unique identifiers, in your browser using the Web Crypto API. Monotonic and lowercase options, bulk generation. Free ULID generator, no signup.
Check URL redirect chains, final destination URL, and HTTP status codes for any link to debug SEO migrations and shortened URLs.
Generate universally unique identifiers (UUIDs) in multiple versions and formats. Perfect for database keys, API identifiers, and unique resource naming.
Create a beautiful, shareable Valentine's Day proposal page. Customize your message, theme, music, and make the 'No' button dodge away! Share the link and see their response.
Look up real-time weather conditions for any city worldwide. Get current temperature, humidity, wind speed, UV index, and sky conditions using the free Open-Meteo API. No API key required.
Verify webhook signatures from Stripe, GitHub, Shopify, or any HMAC provider by recomputing the hash from your payload and secret, fully in your browser.
Check how eco-friendly any website is. Measure CO₂ emissions per page view, page weight, green hosting status, and carbon rating (A+ to F) using the Website Carbon API.
Check if a website is down for everyone or just you. Test website availability, status code, DNS resolution, and response time from an independent server.
Create click-to-chat WhatsApp links. Generate wa.me links, API links, and group invite links for websites and marketing campaigns.
Look up definitions, pronunciations, synonyms, antonyms, and usage examples for any English word. Powered by the Free Dictionary API with audio pronunciation support.
Write and test Zod validation schemas directly in your browser. Paste JSON data, see live field-level error messages and parsed output. Supports the full Zod v3 API. No install required.