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Validate .env files, detect syntax errors, duplicate keys, empty values, potential secrets, compare environments, find missing variables, and review configuration drift.

Free online Age Calculator. Calculate exact chronological age in years, months, days, weeks, hours, minutes, seconds, zodiac signs, and next birthday.

Validate AI.txt syntax, directives, and policy rules directly in your browser. Find line-level errors, review compatibility warnings, and generate a clean AI.txt file.

Free, 100% client-side Base64 encoder and decoder. Convert text, strings, and data to Base64 or Base64URL instantly with UTF-8 support, padding controls, and client-side processing.

Free online Binary Decimal Converter. Convert binary base-2 to decimal base-10 instantly. Supports BigInt, two's complement, 8–256 bit signed, and step breakdown.

Free online color converter. Convert HEX, RGB, RGBA, HSL, CMYK, LAB, OKLCH & CSS color codes instantly with live preview, WCAG contrast checker & developer exports.

Test CORS configuration online, diagnose browser cross-origin errors, inspect CORS headers, test preflight OPTIONS requests, and get actionable server fix recommendations.

Build, validate and understand cron expressions online. Generate cron schedules visually, preview upcoming runs, test time zones and check Unix, Quartz and cloud scheduler syntax.

Crop JPG, PNG, WEBP and other image formats online for free. Supports freeform crop, fixed aspect ratios, rotation, circular crop and batch processing. Everything happens locally in your browser.

Convert CSV to JSON online with file upload, custom delimiters, smart type inference, dot notation unflattening, and JSON preview. 100% client-side conversion.

Convert cURL commands and browser DevTools requests into clean, idiomatic code for JavaScript, Python, Node.js, Go, and PHP. 100% client-side with zero server uploads.

Free online Date Difference Calculator. Calculate days between dates, business days, weeks, months, years, and working hours with interactive timeline.

Free online Decimal to Hex Converter. Convert base-10 to base-16 hexadecimal instantly. Supports BigInt, two's complement, 8–64 bit signed/unsigned, and live steps.

Free online Decimal to Octal converter with instant step-by-step division steps. Convert Base-10 to Base-8 and Octal to Decimal accurately in your browser.

Visualize NPM and project dependencies online. Explore package.json and lockfile dependency trees, trace transitive packages, and inspect dependency relationships directly in your browser.

Visualize Docker Compose files as interactive service dependency graphs and architecture diagrams. Inspect networks, volumes, ports, and dependencies directly in your browser.

Analyze Dockerfiles for syntax errors, security risks, Docker best practices, image optimization opportunities, and build-caching improvements directly in your browser.

Convert Excel files (.xlsx, .xls, .xlsm) to JSON online with multi-worksheet support, raw primitive casting, and JSON preview. 100% client-side conversion.

Generate Fibonacci sequences up to 1,000+ terms or calculate any Nth term instantly. Get exact BigInt results, custom output formats, and Fibonacci number lookup.

Create free, customizable QR codes for websites, Wi-Fi, text and contacts. Generate high-quality static QR codes privately in your browser with no signup.

Calculate the GCD (GCF/HCF) and LCM of two or more numbers instantly. See step-by-step Euclidean algorithm and prime factorization methods with accurate results.

Test GraphQL APIs online with an interactive query editor, variables, headers, schema introspection, documentation explorer, response viewer, and GraphQL error debugging.

Analyze GraphQL API responses online. Inspect data, errors, response paths, null values, structure, and response statistics with a privacy-first browser-based analyzer.

Analyze HTTP Archive (HAR) files online to inspect network requests, response times, status codes, payload sizes, redirects, headers, and performance waterfalls directly in your browser.

Generate hashes and file checksums locally in your browser. Compare digests, copy results, and use MD5, SHA-1, SHA-2, SHA-3, BLAKE2, and supported HMAC algorithms.

Analyze HTTP response headers online, audit security headers (CSP, HSTS, CORS), inspect cookies, detect information disclosure, and review caching policies.

Look up HTTP status codes by number or meaning. Understand 1xx–5xx responses, common causes, API usage, retry guidance, examples, RFC references and related codes.

Compress JPG, PNG and WebP images online for free. Reduce file size while maintaining quality. Everything runs locally in your browser with no uploads.

Convert images between PNG, JPG, JPEG, WEBP, BMP, ICO and AVIF directly in your browser. Fast, private, secure and completely free.

Resize JPG, PNG and WebP images online for free. Change image dimensions while preserving quality. Everything happens locally in your browser.

Instantly sort JavaScript and TypeScript import statements online. Reorder ES6 imports by path and organize dependencies with a fast browser-based import sorter.

Free online IP subnet calculator. Calculate CIDR notation, subnet masks, network addresses, broadcast ranges, usable hosts, and wildcard masks instantly.

Open and inspect Java KeyStore (JKS), PKCS12, PFX and JCEKS files directly in your browser.

Compare two JSON files or objects online and find structural differences instantly. Detect added, removed, and modified values with nested key paths in your browser.

Free online JSON formatter, beautifier, and validator. Format, indent, minify, and inspect JSON with real-time syntax error detection in your browser. 100% client-side.

Compare two JSON Schema versions and identify added, removed, and modified fields, type changes, constraint changes, required-field changes, and potential breaking changes.

Instantly generate JSON Schema from any JSON payload. Supports Draft 7 and Draft 2020-12 with fast, browser-based processing.

Validate JSON data against a JSON Schema online with detailed errors, JSON paths, draft detection, and browser-based processing.

Convert JSON to CSV online with support for arrays, nested objects, custom delimiters and Excel-friendly CSV output. Fast browser-based conversion.

Convert JSON data to Excel (.xlsx) online. Flatten nested objects, preview spreadsheet data, and download an Excel workbook directly from your browser.

Free online multi-engine JSON transformer. Filter, reshape, map, and restructure complex JSON payloads using JavaScript, jq, JSONPath, and Jolt specifications with 100% client-side Web Worker execution, live preview, and Monaco editors.

Decode JWT tokens instantly in your browser. Inspect headers, payload claims, verify signatures, convert timestamps, and debug JWTs securely with 100% client-side processing.

Remove solid-color backgrounds entirely inside your browser. No uploads, no login, unlimited use.

Generate Lorem Ipsum placeholder text instantly. Create custom paragraphs, sentences, words, lists, or HTML for web design, UI mockups, prototypes, and development.

Create and edit Markdown tables online. Paste CSV, TSV, Excel or Google Sheets data, import Markdown, preview the result, align columns and copy clean GitHub-compatible Markdown.

Write, edit, and live-preview Mermaid.js diagrams directly in your browser. A fast, free, and private online Mermaid editor with instant PNG and SVG export.

Generate realistic mock data instantly in your browser. Build custom schemas, choose field types, and export test datasets to JSON, CSV, or SQL.

Check licenses for NPM and Node.js dependencies online. Inspect package versions, license identifiers, direct and transitive dependencies, and export a license inventory when supported.

Interactive engineering workspace for Bisection, Newton-Raphson, Secant, Simpson's, Gaussian Elimination, and RK4.

Use ToolMono's free online calculator for quick everyday math, expressions, percentages, powers, roots, and parentheses. Includes calculation history and keyboard support.

Free online CSV validator. Check CSV syntax, detect unclosed quotes, find row and column mismatches, and validate delimiters directly in your browser.

Sanitize HAR files online by redacting cookies, Authorization headers, Bearer tokens, and other sensitive data directly in your browser.

Build and sign JSON Web Tokens online for API testing and development. Customize JWT claims and generate signed tokens directly in your browser with 100% client-side processing.

Scan and decode QR codes online using your camera, image files, or screenshots. Free browser-based QR scanner with local processing and no app installation.

Validate SQL query syntax online for supported SQL dialects. Detect syntax errors, locate line and column issues, and check queries instantly without a database connection.

Instantly parse any URL online. Extract scheme, hostname, path, query parameters, and fragments directly in your browser with 100% client-side privacy.

Generate secure UUID v4 and time-ordered UUID v7 identifiers online. Create single or bulk UUIDs with formatting controls, GUID support, and client-side Web Crypto generation.

Free online YAML validator and syntax checker. Check YAML syntax, find indentation and parsing errors, and debug YAML directly in your browser.

Instantly preview how your link looks on Facebook, Twitter, LinkedIn, and WhatsApp. Debug missing Open Graph tags, validate images, and fix your social media metadata with our professional-grade Open Graph Checker.

Compare two OpenAPI or Swagger specifications online and detect breaking changes instantly. Compare endpoints, parameters, request bodies, response schemas, and security requirements in your browser.

Generate ready-to-use API requests from OpenAPI and Swagger specifications. Select an endpoint, configure parameters and authentication, and instantly generate cURL, JavaScript Fetch, Axios, Python Requests, Node.js, and Raw HTTP examples.

Generate realistic mock API responses from OpenAPI and Swagger specifications. Select an endpoint and response status, resolve schemas and $ref references, customize mock data, and export ready-to-use mock fixtures or server code entirely in your browser.

Validate, lint, and audit OpenAPI 3.2, 3.1, 3.0 and Swagger 2.0 specifications in JSON or YAML. Detect syntax errors, broken $ref pointers, path issues, security vulnerabilities, and API design warnings in your browser.

Free online package.json viewer and explorer. Inspect npm dependencies, scripts, metadata, entry points, and Node.js configuration directly in your browser.

View, inspect, and query Apache Parquet files online instantly in your browser. 100% private local processing using WebAssembly. View schemas, metadata, and export to CSV or JSON.

Use free online PDF tools to merge, split, compress, convert, edit, sign, and organize PDF files. Fast browser-based utilities with no installation required.

Free, 100% client-side PEM Certificate Decoder. Inspect X.509 fields, SANs, validity dates, fingerprints, and issuer details instantly in your browser.

Calculate percentages instantly with ToolMono's free online percentage calculator. Find X% of Y, calculate what percent X is of Y, and solve reverse percentages.

Convert your Postman Collection (JSON v2.0/2.1) to OpenAPI 3.0/3.1 specs instantly. Browser-based, secure, and free. No login required.

Check if a number is prime or composite instantly. Get factors, prime factorization, trial-division details, and neighboring prime numbers with this free online prime checker.

Compare two project folders, directories, or ZIP files online. Find added, removed, and modified files and inspect side-by-side content differences directly in your browser.

Count AI and LLM tokens in prompts, code, JSON, and text. Compare token usage by supported encodings with browser-based processing and no prompt uploads.

Free online random generator for numbers, list selections, and random text. Generate results instantly in your browser with useful presets and copy options.

Test JavaScript regular expressions with live match highlighting, capture-group inspection, flags, and replacement preview. 100% client-side privacy.

Parse and inspect requirements.txt files online. Analyze Python dependencies, version specifiers, extras, markers, and pinning directly in your browser.

Validate and test robots.txt files online. Check syntax, Allow/Disallow rules, Googlebot access, URL crawlability, sitemaps, AI crawlers, and SEO issues with exact winning-rule explanations.

Use ToolMono's free Scientific Calculator for advanced mathematical calculations. Supports trigonometric, inverse, hyperbolic, logarithmic, exponential, factorial, scientific notation, degree/radian modes, calculation history, and 100% client-side processing.

Generate strong random passwords and memorable passphrases instantly in your browser. Customize length, characters, and options with browser-based cryptographic randomness.

Free online SQL formatter and beautifier. Format, indent, and clean up SQL queries instantly in your browser. Supports MySQL, PostgreSQL, T-SQL, and Oracle.

Minify SQL queries instantly in your browser. Remove extra whitespace, newlines, and comments to compact SQL payloads while preserving query logic. 100% client-side.

Inspect SQL statement structure, detect anti-patterns, evaluate query complexity, and generate plain-English summaries directly in your browser.

Calculate your attendance percentage, find how many classes you can miss, and see how many classes you need to attend to reach 75%, 80%, or any target.

Convert Tailwind CSS classes to inline style attributes instantly. Free online HTML email inliner with Tailwind v3 & v4 support, responsive fallbacks, and live preview.

Convert text online to UPPERCASE, lowercase, Title Case, Sentence case, Capitalized Case, Toggle Case, camelCase, snake_case and more.

Compare two texts online and find differences instantly. Highlight changes line-by-line, word-by-word, or character-by-character with a fast browser-based diff checker.

Convert Unix timestamps to dates and dates to timestamps instantly. Supports seconds, milliseconds, microseconds, nanoseconds, UTC, local time, and ISO 8601.

Free, 100% client-side URL encoder and decoder. Convert text and query parameters into RFC 3986 percent-encoded strings or decode URLs with smart double-encoding detection and structural URL analysis.

Parse and analyze User-Agent strings online. Identify browser, version, operating system, device, rendering engine, CPU hints, bots, and Client Hints with batch parsing and JSON/CSV export.

Generate a free temporary webhook URL to capture, inspect, and debug incoming HTTP payloads, headers, and JSON in real time. Replay requests instantly.

Free word and character counter for essays, blogs, students, SEO, social media and everyday writing.

Free online XML to JSON converter. Instantly translate XML payloads, SOAP responses, and RSS feeds to JSON with 100% client-side privacy, namespace support, CDATA preservation, attribute mapping, line-level error detection, and pretty/minified formatting.

Free online XML validator and syntax checker. Instantly check XML well-formedness, find line-level errors, and troubleshoot XML code securely in your browser.

Free online YAML to JSON converter. Instantly translate Kubernetes manifests, Docker Compose files, and GitHub Actions workflows to JSON with 100% client-side privacy, multi-document support, line-level error detection, anchors, aliases, and pretty/minified formatting.