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Essential tools for web developers, programmers, and software engineers.
Showing 36 tools
Beautify, minify, sort, repair and validate JSON with precise error location, a collapsible tree view and path queries.
Open ToolUTF-8-safe Base64 encode & decode with a URL-safe variant, line-wrapping and file-to-Base64 (data URI).
Open ToolEncode and decode URLs and components, with a live breakdown of query parameters.
Open ToolDecode and inspect a JWT's header, payload and claims with human-readable timestamps and live expiry status.
Open ToolGenerate MD5, SHA-1, SHA-256, SHA-384, SHA-512 and HMAC digests for text or files.
Open ToolTest and debug regular expressions with live match highlighting, capture groups, replace and example patterns.
Open ToolMinify HTML, strip comments and whitespace while protecting pre/script/style, with a size-saved readout.
Open ToolMinify CSS, remove comments and whitespace safely (strings and data URIs preserved) with a size-saved readout.
Open ToolConvert JSON to YAML and YAML back to JSON, bidirectional, no server round-trip.
Open ToolConvert CSV data into a JSON array of objects, with smart number and boolean detection.
Open ToolConvert a JSON array of objects into clean, spreadsheet-ready CSV.
Open ToolConvert Markdown text into clean HTML you can paste straight into a website.
Open ToolConvert your Markdown (.md) files to high-quality PDFs instantly. Fast, free, secure, and works directly in your browser with no installation or signup required.
Open ToolGenerate UUID v4, time-ordered UUID v7, NIL, ULID and NanoID, cryptographically random, in bulk.
Open ToolConvert color codes between HEX, RGB and HSL formats in one click.
Open ToolGenerate TypeScript, Go, Python, Rust and JSON Schema from a JSON sample.
Open ToolGenerate strong, secure passwords.
Open ToolCompare code snippets and show differences.
Open ToolCalculate Unix file permissions in numeric and symbolic notation side by side.
Open ToolRemove whitespace from JSON for smaller payload size.
Open ToolBeautify and format SQL queries with consistent indentation and keyword casing.
Open ToolFormat and beautify XML documents.
Open ToolEncode and decode HTML entities so special characters render correctly.
Open ToolParse and analyze HTTP response headers.
Open ToolBuild, describe in plain English and preview the next run times of cron schedules.
Open ToolCreate JWT tokens for testing and development.
Open ToolSend HTTP requests and inspect responses.
Open ToolGenerate multiple UUIDs at once (up to 10,000).
Open ToolCommon regex patterns with testing, ready to copy and use.
Open ToolQuery JSON with JSONPath ($, wildcards, recursive descent, slices) and explore every path to a value.
Open ToolEscape and unescape strings for JSON, JavaScript, HTML, URL, CSV, SQL, RegExp, shell and Unicode.
Open ToolParse a URL or query string into editable params and build it back: arrays, encoding and JSON output.
Open ToolInfer a JSON Schema (draft-07) from a JSON sample: types, required, formats and enums.
Open ToolSemantic, order-independent diff of two JSON documents: added, removed and changed values by path.
Open ToolGenerate realistic fake JSON, CSV or SQL test data from a simple field schema: names, emails, dates, UUIDs and more.
Open ToolBuild cURL commands from a request and convert them to fetch or axios code, and parse cURL back.
Open ToolDeveloper tools are for the moments between real work: an API response that arrives as one unreadable line, a JWT you need to inspect, a cron expression you have to get right before it runs in production. The JSON Formatter, XML Formatter and SQL Formatter make payloads and queries readable, the JWT Decoder shows a token's claims, and the Cron Expression Generator explains a schedule in plain words.
They also convert and generate. JSON can become YAML, CSV or TypeScript types, the Regex Tester and the Regex Pattern Library help write a pattern and see what it matches, and the UUID, password and mock data generators produce test values. Everything here runs in your browser, so pasting a production payload or a token does not send it anywhere.
Every tool in this category runs entirely in your browser, so nothing you paste or open is uploaded. Where your files are processed lists this for every tool on the site.
Practical how-tos from the ToolsMonk blog that use the tools in this category.
Testing APIs is a daily task for modern developers. Learn how to test REST APIs efficiently using cURL commands, Postman collections, and browser developer tools, with practical examples for common scenarios.
Read the guideJSON is the universal data format powering APIs, configs, and databases. Everything you need to know about JSON formatting, validation, beautification, and best practices, with free online tools to speed up your workflow.
Read the guideJSON Web Tokens power authentication in millions of web applications. Understand how JWTs work, their structure, security considerations, and best practices for implementing stateless authentication in your projects.
Read the guideMessy, inconsistent code is harder to read, debug, and maintain. Learn how code beautification tools and consistent formatting standards improve code quality, team collaboration, and long-term maintainability.
Read the guideOne of our pages answered 2,318,515 bytes and 82.7% of that was props serialized into the HTML, not content. Here is how Client Component props get shipped twice, the projection that cut the page by 76%, and the measuring mistake that first told us everything was fine.
Read the guideBase64 encoding is everywhere in web development, from data URIs and email attachments to API tokens and image embedding. Master Base64 encoding/decoding with practical examples and ToolsMonk's free converter.
Read the guideCommon questions about developer tools, the tools available in this category, and how to choose the right workflow.