Free online developer tools that just work
Format, validate, convert, compare and run code in one place. Premium tools with a clean interface, built for everyday engineering work.
- 148 free tools
- Most tools run in your browser
- No sign-up
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Popular tools
Online C and C++ compilers, an HTML viewer, formatters and converters people open most.
C Compiler
Compile and run C code online with Clang 21, a GCC-compatible compiler: pick C89 (ANSI C), C99, C11, C17 or C23 and add stdin input. Your code stays private.
C++ Compiler
Run C++ code online for free: compile C++20 with Clang 21 and libc++, type stdin input and see the output. It runs in your browser, so your code stays private.
HTML Viewer
Free online HTML viewer: paste HTML code and see it rendered live in a secure sandboxed preview. Check snippets, emails and templates with scripts off.
PHP Formatter
Format PHP code online with Prettier for PHP (@prettier/plugin-php): PSR-12 braces, spacing and 4-space indentation. No install, and nothing is uploaded.
Unix Timestamp Converter
Convert a Unix timestamp (epoch time) in seconds or milliseconds to a readable date and back, in any time zone, and see the current Unix time live.
HTML to PDF Converter
Convert HTML to a downloadable PDF online with live preview, paper sizes, orientation, margins, page breaks and page numbers. Your file is not stored.
URL Encode / Decode
URL encode or decode text online: percent-encode query string values and full URLs, or turn %20-style escapes back into readable text.
Base64 Encode / Decode
Decode Base64 to text or encode text to Base64 online, with full UTF-8 and URL-safe Base64 support. Conversion runs in your browser, so nothing is uploaded.
Text to Binary
Free binary translator: convert text to binary code and translate binary back to English or any language, with a binary alphabet table. Copy or download the result.
JSON Formatter
Format and beautify JSON with configurable indentation and optional key sorting. Errors are reported with exact line and column.
Image Compressor
Compress JPG, PNG and WebP images online to an exact size like 20 KB, 50 KB or 100 KB for upload forms, or by quality. Images never leave your browser.
Compress PDF
Compress PDF files online to a size limit like 100 KB, 200 KB or 500 KB for upload forms, or by level. Text stays sharp where possible. Nothing is uploaded.
JPG & PNG to PDF
Convert JPG, PNG and WebP images to one PDF online. Reorder pages, choose A4, Letter or image size, orientation and margins. Photos stay on your device.
Popular guides
Programming LanguagesGCC vs Clang: What Is the Difference for C Programmers?
GCC vs Clang compared with real output: error messages, warnings, GNU extensions, undefined behaviour, flags and platforms, and which one to use for C code.
· 12 min read
Time & SchedulingCron Expressions Explained: Syntax, Examples and Common Mistakes
What a cron expression is and how to read one: the five fields, special characters, 20 tested examples, the day-of-week OR trap, time zones and DST.
· 9 min read
Programming LanguagesC Compiler Errors and Warnings, Explained With Fixes for Clang and GCC
What common C compiler errors and warnings mean, from a missing semicolon to an undefined reference, with real Clang and GCC output and the fix for each.
· 7 min read
Security & EncodingURL Encoding Explained: Percent-Encoding, encodeURIComponent and Common Bugs
How percent-encoding works, when to use encodeURIComponent vs encodeURI, why + sometimes means a space, and how to fix double encoding and broken query strings.
· 5 min read
Developer Tools
Format, minify, validate, view, encode and decode JSON, HTML, CSS, JavaScript, TypeScript, PHP, SQL, XML, JWT and more. Everything runs locally in your browser.
JSON Formatter
Format and beautify JSON with configurable indentation and optional key sorting. Errors are reported with exact line and column.
HTML Formatter
Format and beautify messy or minified HTML into clean, indented markup with Prettier, including embedded CSS and JavaScript. Runs locally in your browser.
CSS Formatter
Format and beautify CSS, SCSS and Less online with Prettier. Turn minified or messy stylesheets into readable, consistently indented code in your browser.
JavaScript Formatter
Format and beautify JavaScript and JSX online with Prettier. Choose indentation, quotes, semicolons and line width; your code is formatted in your browser.
TypeScript Formatter
Format and beautify TypeScript and TSX online with Prettier, including types, generics and decorators. Choose indentation, quotes and semicolons.
PHP Formatter
Format PHP code online with Prettier for PHP (@prettier/plugin-php): PSR-12 braces, spacing and 4-space indentation. No install, and nothing is uploaded.
Diff Checker
Compare two texts or code files side by side. Added, removed and modified lines are highlighted with inline word changes. Copy or download the unified diff.
Text & Code Diff
Compare two texts or code files online side by side. Additions, deletions and modified lines are highlighted with inline word changes. Runs in your browser.
JSON Diff
Compare two JSON documents online, ignoring key order and formatting. Keys are normalised and sorted, so only real changes in values are highlighted.
Online Compilers
Write and run C, C++, Python, Go, JavaScript, TypeScript, PHP, Ruby, R and SQL online. Code runs in a sandbox in your browser and never leaves your device.
JavaScript Compiler
Run JavaScript online in an isolated browser sandbox. See console output, errors and execution time instantly, with top-level await and stdin input.
TypeScript Compiler
Compile and run TypeScript online. Your code is type-checked with the official compiler in strict mode, then runs in a sandboxed worker in your browser.
Python Compiler
Run Python 3 code online with the full standard library and stdin input. It runs in your browser with Pyodide (WebAssembly), so your code stays on your device.
PHP Compiler
Run PHP 8.4 code online and see the output instantly, with stdin input and mbstring. PHP runs in your browser with WebAssembly, so your code stays private.
C Compiler
Compile and run C code online with Clang 21, a GCC-compatible compiler: pick C89 (ANSI C), C99, C11, C17 or C23 and add stdin input. Your code stays private.
C++ Compiler
Run C++ code online for free: compile C++20 with Clang 21 and libc++, type stdin input and see the output. It runs in your browser, so your code stays private.
Converters
Convert between JSON, CSV, XML, YAML, PHP arrays, TypeScript interfaces, SQL and more with validation and downloadable results.
JSON to CSV
Convert JSON arrays to CSV online with automatic column detection, nested object flattening and custom delimiters. Open the result in Excel or Sheets.
CSV to JSON
Convert CSV to a JSON array online with header detection, type inference and delimiter auto-detection. Turn spreadsheet exports into data for APIs and code.
JSON to XML
Convert JSON to well-formed XML online with a configurable root element and attribute support. Validate the input and download the XML file.
XML to JSON
Convert XML to JSON online, keeping attributes and turning repeated elements into arrays. Malformed XML is reported with its location.
JSON to YAML
Convert JSON to clean, human-readable YAML online. Turn API responses and package files into config for Kubernetes, Docker Compose or CI pipelines.
YAML to JSON
Convert YAML documents to formatted JSON online with syntax validation. Errors are reported by line, so broken indentation is quick to find and fix.
Image Tools
Remove image backgrounds with AI, compress, resize, crop and convert JPEG, PNG and WebP, and encode images to Base64. Everything runs in your browser.
Background Remover
Remove the background from photos free with AI: full HD resolution, bulk images, transparent PNG or white background. No upload, no sign-up, no watermark.
Passport Photo Maker
Make passport and visa photos online: US 2×2 in, UK, Schengen, India 3.5×4.5 cm and more, with AI white background, head guides and a 4×6 print sheet. No upload.
Image to Text (OCR)
Extract text from images, screenshots and scanned PDFs with free OCR in your browser. English, Hindi and 20 more languages; nothing is uploaded.
Image to Word
Convert photos, screenshots and scanned PDFs into an editable Word document with free OCR in your browser. English, Hindi and 20 more languages.
Image Compressor
Compress JPG, PNG and WebP images online to an exact size like 20 KB, 50 KB or 100 KB for upload forms, or by quality. Images never leave your browser.
Image Resizer
Resize images online to exact pixels, a percentage or presets like 1200×630 for Open Graph. Crop to fill, pad or stretch, in batches, without uploading.
PDF Tools
Merge, compress, split, organize and rotate PDFs, add page numbers and watermarks, and convert PDF to JPG or back. Files are processed in your browser.
Merge PDF
Merge PDF files online in the order you choose: drag to reorder, see page counts, and download one combined PDF. Files never leave your browser.
Compress PDF
Compress PDF files online to a size limit like 100 KB, 200 KB or 500 KB for upload forms, or by level. Text stays sharp where possible. Nothing is uploaded.
PDF to JPG & PNG
Convert PDF pages to JPG or PNG images online at 72, 150 or 300 dpi. Pick all pages or a range and download them one by one or as a ZIP, privately.
JPG & PNG to PDF
Convert JPG, PNG and WebP images to one PDF online. Reorder pages, choose A4, Letter or image size, orientation and margins. Photos stay on your device.
PDF to Word
Convert PDF to an editable Word document in your browser. Keeps headings, bold text, lists and pictures; scanned pages are read with OCR. Free.
Word to PDF
Convert Word DOCX files to PDF in your browser, keeping page size, margins, headings, lists, tables and images. Hindi and ₹ supported; no upload.
Generators
Create email signatures from ready-made templates, and generate secure passwords, UUIDs, QR codes, test data, hashes, lorem ipsum, meta tags and CSS gradients.
Email Signature Generator
Create a professional email signature from ready-made templates, or paste your own HTML. Copy it into Gmail, Outlook or Apple Mail, or download the HTML.
Password Generator
Generate strong, random passwords online with your browser's cryptographically secure generator. Choose length and character sets; check the strength meter.
UUID Generator
Generate UUID v4 and time-ordered UUID v7 identifiers (GUIDs) in bulk, with uppercase, hyphen and brace options, using a cryptographically secure generator.
Large CSV Generator
Generate realistic fake test data (names, emails, phones, companies, addresses, IDs and dates) and download it as CSV or Excel (.xlsx). Free, in your browser.
QR Code Generator
Create free QR codes online for websites and text, with custom size, colours and error correction. Live preview, and download as PNG or SVG.
Barcode Generator
Create barcodes online: Code 128, EAN-13, UPC-A, EAN-8 and Code 39 with check digits added for you. Download as PNG or SVG for labels and print.
SEO Tools
Free SEO tools for developers: generate robots.txt, XML sitemaps, schema markup, Open Graph tags and UTM links, and preview Google snippets in your browser.
Website SEO Checker
Check any page for on-page SEO problems: title, meta description, headings, canonical, robots.txt, noindex, structured data, alt text, HTTPS and speed, with a score.
Broken Link Checker
Find broken links on any web page: every internal and external link (and optionally image) is checked for 404s, server errors, timeouts and redirects. Export a CSV.
Redirect Checker
Check the HTTP status code and full redirect chain of up to 100 URLs: 301, 302, 404 and 5xx, response headers, loops and HTTPS downgrades, with fixes and CSV.
HTTP Status Checker
Check the HTTP status code of up to 100 URLs: 200, 301, 404, 500 and more, with what each means for SEO and a searchable list of every status code.
AdSense Readiness Checker
Check if your site is ready for Google AdSense: privacy policy, About and Contact pages, ads.txt, crawler access, thin pages, content risks and consent, before you apply.
Site Audit Tool
Crawl your website (up to 100 pages) and find broken pages, duplicate titles and descriptions, missing H1s, redirects, noindex, thin and slow pages. Export a CSV.
Time & Date
See the current time anywhere, convert between time zones with correct daylight saving handling, and convert Unix timestamps.
World Clock
See the current time in any two time zones online, with UTC offsets, the time difference and upcoming daylight saving changes. Compare cities at a glance.
Time Zone Converter
Convert a date and time between time zones online with correct daylight saving handling, including gaps and overlaps. Compare EST, PST, GMT, CET, IST and more.
Unix Timestamp Converter
Convert a Unix timestamp (epoch time) in seconds or milliseconds to a readable date and back, in any time zone, and see the current Unix time live.
Date Difference Calculator
Calculate the exact difference between two dates online in years, months, days, hours and business days. Count days until a deadline or since an event.
From the blog
Practical guides to the formats, encodings and techniques behind these tools.
Web DevelopmentGEO Checklist: How to Get Your Pages Into AI Answers (2026)
What Google, OpenAI and Anthropic actually require before AI answers can cite your page, what Google says to ignore, and an 8-point GEO checklist to test it.
· 6 min read
Web DevelopmentA New Website's First 3 Weeks on Google: Real Search Console Data
Real Search Console and Bing numbers from a brand-new site: when pages got indexed, which ranked first, why blog posts beat tool pages, and what we changed.
· 5 min read
Web DevelopmentWho Blocks AI Crawlers? A robots.txt Study of the Top 1,000 Sites (2026)
We read the robots.txt of the top 1,000 sites: 31% block at least one AI crawler, GPTBot is blocked twice as often as ChatGPT search, and 11% have llms.txt.
· 5 min read
Why Devtoolry
Private by default
Formatting, conversion and generation run in your browser. Nothing is uploaded.
Fast and focused
Each tool loads only the code it needs, with a distraction-free editor.
Sandboxed execution
Compilers run your code in isolated workers in your browser, never on our servers.
Built by
Avinash Kori
Founder of Devtoolry · Surat, India
Avinash is a full-stack web developer from Surat, India, with eight years of experience in PHP, Laravel and Angular. He built Devtoolry so developers can solve everyday problems quickly with free tools that run entirely in the browser, and writes practical guides on the formats, encodings and techniques behind them.
Missing a tool or found a bug? Send feedback: requests decide what gets built next.
Connect on LinkedIn (opens in a new tab)More about Devtoolry
Frequently asked questions
Are the Devtoolry tools really free?
Yes. Every tool works without an account and without a trial. A free account only adds saved keyword projects. A Pro plan for extras such as ad-free pages is planned; the tools themselves stay free.
Is my code or data uploaded?
Formatters, converters, generators, the diff checker, the PDF and image tools and every compiler run in your browser, so your input never reaches our server. The exceptions are clearly marked on their pages: HTML to PDF renders on our server, and the SEO checkers fetch the public pages you ask about. None of them store what you send.
Do the compilers run my code on a server?
No. C, C++, Go, Python, PHP, Ruby, R, JavaScript, TypeScript and SQL run as WebAssembly or in a Web Worker inside your browser tab, isolated from the page. Your source code and input are never sent to a server.
Do I need to install anything?
No. Everything opens in a modern browser on desktop or phone; the heavier tools (compilers, background remover, OCR) download their engine the first time you use them.
Who builds Devtoolry?
Devtoolry is built by Avinash Kori, a full-stack developer from Surat, India. Requests and bug reports through the feedback page decide what gets built next.
