DevTol — Client-Side Developer Utilities & Web Engineering Suite
Over 124+ client-side developer and designer utilities running entirely in your browser sandbox using Web Workers, WebAssembly, and the Web Crypto API. Zero server transmissions, absolute data privacy, and instantaneous local processing.
Comprehensive Developer Tools Directory (124+ Tools)
PDF Editor
100% Free Client-Side PDF Editor. Edit PDF text directly, find & replace text with full Arabic support, load system fonts, add signatures, draw, and redact PDFs securely in your browser.
Merge PDF
Merge multiple PDF files into one. 100% client-side - files never leave your browser.
Split PDF
Split or extract specific pages from a PDF file. Client-side processing, total privacy.
Compress PDF
Reduce PDF file size with adjustable quality. 100% browser-based, no uploads.
PDF to Image
Convert PDF pages to PNG or JPG images. Download all pages as a ZIP. Client-side only.
Images to PDF
Convert JPG, PNG, or WebP images into a single PDF document. No server uploads.
PDF Protect & Unlock
Password-protect or unlock PDF files directly in your browser. Zero server uploads.
Organize PDF Pages
Reorder and rotate PDF pages visually. Drag and rearrange pages then download.
PDF OCR Text Extractor
Extract text from scanned PDFs and images using OCR. Supports multiple languages.
PDF Redaction Tool
Permanently redact sensitive text from PDF files. Client-side privacy guaranteed.
PDF Watermark
Add text watermarks to all pages of a PDF. Custom position, opacity, and font.
AI token & LLM cost calculator
Estimate prompt tokens via BPE heuristic and compare live pricing across OpenAI, Anthropic, Gemini, and DeepSeek with prompt caching discounts.
AI regex generator & structural explainer
Generate regular expressions from natural language prompts, disassemble pattern structures, test live strings with capture groups, and export production code.
SQL to ORM schema converter
Convert raw SQL CREATE TABLE DDL statements into Prisma schemas, SQLAlchemy 2.0 models, Drizzle ORM, TypeORM, Go GORM, and TypeScript interfaces.
Image Compressor
Compress JPG, PNG, and WebP images up to 90% smaller. Real-time preview, no uploads.
WebP Converter
Convert WebP to PNG/JPG or convert PNG/JPG to WebP format. Client-side processing.
Image Resizer & Cropper
Resize images to exact dimensions or crop to standard aspect ratios. No server uploads.
SVG to PNG/JPG Converter
Convert SVG vector files to PNG, JPG at any scale. Upload file or paste SVG code.
EXIF Metadata Viewer
View and strip EXIF metadata from photos. See camera settings, GPS location and more.
Video to GIF
Convert video clips to animated GIF. Set start/end time, size and FPS. Client-side.
Color Palette Generator
Generate color palettes, convert between HEX/RGB/HSL/CMYK and check WCAG contrast ratios.
Favicon Generator
Generate all favicon sizes (16x16 to 512x512) and app icons from a single image. Download as ZIP.
Image Watermark
Add text or image watermarks to photos with custom position, opacity and style.
QR Code Scanner
Scan QR codes from images or your camera. Detects URLs, WiFi, vCards and plain text.
Word & Character Counter
Count words, characters, sentences, paragraphs and estimate reading time in real-time.
Regex Find & Replace
Find and replace text using regular expressions with live preview and match highlighting.
Text Sorter & Deduplicator
Sort lines, remove duplicates, trim whitespace and clean text. Multiple sort options.
YAML Validator & Formatter
Validate, format, and convert YAML to JSON. Get detailed syntax error messages.
Text Encrypt & Decrypt
Encrypt and decrypt text with AES-GCM using a password. Runs 100% in your browser.
JWT Builder & Signer
Build, sign and decode JSON Web Tokens with custom header, payload and HMAC-SHA256 secret.
Image OCR Text Extractor
Extract text from images using OCR. Supports English, Arabic, French, German and more.
Mock Data Generator
Generate realistic dummy data: names, emails, addresses, UUIDs, dates. Export as JSON or CSV.
Line Deduplicator
Remove duplicate lines, sort, trim whitespace and clean text lists instantly.
Text to Speech
Convert text to audio with browser-native speech synthesis. Adjust voice, speed, and pitch.
Token generator
Generate random string with the chars you want, uppercase or lowercase letters, numbers and/or symbols.
Hash text
Hash a text string using the function you need : MD5, SHA1, SHA256, SHA224, SHA512, SHA384, SHA3 or RIPEMD160
Bcrypt
Hash and compare text string using bcrypt. Bcrypt is a password-hashing function based on the Blowfish cipher.
UUIDs generator
A Universally Unique Identifier (UUID) is a 128-bit number used to identify information in computer systems. The number of possible UUIDs is 16^32, which is 2^128 or about 3.4x10^38 (which is a lot!).
ULID generator
Generate random Universally Unique Lexicographically Sortable Identifier (ULID).
Encrypt / decrypt text
Encrypt clear text and decrypt ciphertext using crypto algorithms like AES, TripleDES, Rabbit or RC4.
BIP39 passphrase generator
Generate a BIP39 passphrase from an existing or random mnemonic, or get the mnemonic from the passphrase.
Hmac generator
Computes a hash-based message authentication code (HMAC) using a secret key and your favorite hashing function.
RSA key pair generator
Generate a new random RSA private and public pem certificate key pair.
Password strength analyser
Discover the strength of your password with this client-side-only password strength analyser and crack time estimation tool.
PDF signature checker
Verify the signatures of a PDF file. A signed PDF file contains one or more signatures that may be used to determine whether the contents of the file have been altered since the file was signed.
Date-time converter
Convert date and time into the various different formats
Integer base converter
Convert a number between different bases (decimal, hexadecimal, binary, octal, base64, ...)
Roman numeral converter
Convert Roman numerals to numbers and convert numbers to Roman numerals.
Base64 string encoder/decoder
Simply encode and decode strings into their base64 representation.
Base64 file converter
Convert a string, file, or image into its base64 representation.
Color converter
Convert color between the different formats (hex, rgb, hsl and css name)
Case converter
Transform the case of a string and choose between different formats
Text to NATO alphabet
Transform text into the NATO phonetic alphabet for oral transmission.
Text to ASCII binary
Convert text to its ASCII binary representation and vice-versa.
Text to Unicode
Parse and convert text to unicode and vice-versa
YAML to JSON converter
Simply convert YAML to JSON with this online live converter.
YAML to TOML
Parse and convert YAML to TOML.
JSON to YAML converter
Simply convert JSON to YAML with this online live converter.
JSON to TOML
Parse and convert JSON to TOML.
List converter
This tool can process column-based data and apply various changes (transpose, add prefix and suffix, reverse list, sort list, lowercase values, truncate values) to each row.
TOML to JSON
Parse and convert TOML to JSON.
TOML to YAML
Parse and convert TOML to YAML.
XML to JSON
Convert XML to JSON
JSON to XML
Convert JSON to XML
Markdown to HTML
Convert Markdown to Html and allow to print (as PDF)
Encode/decode URL-formatted strings
Encode text to URL-encoded format (also known as "percent-encoded"), or decode from it.
Escape HTML entities
Escape or unescape HTML entities (replace characters like <,>, &, " and \' with their HTML version)
URL parser
Parse a URL into its separate constituent parts (protocol, origin, params, port, username-password, ...)
Device information
Get information about your current device (screen size, pixel-ratio, user agent, ...)
Basic auth generator
Generate a base64 basic auth header from a username and password.
Open graph meta generator
Generate open-graph and socials HTML meta tags for your website.
OTP code generator
Generate and validate time-based OTP (one time password) for multi-factor authentication.
MIME types
Convert MIME types to file extensions and vice-versa.
JWT parser
Parse and decode your JSON Web Token (jwt) and display its content.
Keycode info
Find the javascript keycode, code, location and modifiers of any pressed key.
Slugify string
Make a string url, filename and id safe.
HTML WYSIWYG editor
Online, feature-rich WYSIWYG HTML editor which generates the source code of the content immediately.
User-agent parser
Detect and parse Browser, Engine, OS, CPU, and Device type/model from an user-agent string.
HTTP status codes
The list of all HTTP status codes, their name, and their meaning.
JSON diff
Compare two JSON objects and get the differences between them.
Outlook Safelink decoder
Decode Outlook SafeLink links
QR Code generator
Generate and download a QR code for a URL (or just plain text), and customize the background and foreground colors.
WiFi QR Code generator
Generate and download QR codes for quick connections to WiFi networks.
SVG placeholder generator
Generate svg images to use as a placeholder in your applications.
Camera recorder
Take a picture or record a video from your webcam or camera.
Git cheatsheet
Git is a decentralized version management software. With this cheatsheet, you will have quick access to the most common git commands.
Random port generator
Generate random port numbers outside of the range of "known" ports (0-1023).
Crontab generator
Validate and generate crontab and get the human-readable description of the cron schedule.
JSON prettify and format
Prettify your JSON string into a friendly, human-readable format.
JSON minify
Minify and compress your JSON by removing unnecessary whitespace.
JSON to CSV
Convert JSON to CSV with automatic header detection.
SQL prettify and format
Format and prettify your SQL queries online (it supports various SQL dialects).
Chmod calculator
Compute your chmod permissions and commands with this online chmod calculator.
Docker run to Docker compose converter
Transforms "docker run" commands into docker-compose files!
XML formatter
Prettify your XML string into a friendly, human-readable format.
YAML prettify and format
Prettify your YAML string into a friendly, human-readable format.
Email normalizer
Normalize email addresses to a standard format for easier comparison. Useful for deduplication and data cleaning.
Regex Tester
Test your regular expressions with sample text.
Regex cheatsheet
Javascript Regex/Regular Expression cheatsheet
cURL to code converter
Convert cURL commands into clean, production-ready code in Python, JavaScript, TypeScript, Go, PHP, Rust, and Java with 100% client-side privacy.
IPv4 subnet calculator
Parse your IPv4 CIDR blocks and get all the info you need about your subnet.
IPv4 address converter
Convert an IP address into decimal, binary, hexadecimal, or even an IPv6 representation of it.
IPv4 range expander
Given a start and an end IPv4 address, this tool calculates a valid IPv4 subnet along with its CIDR notation.
MAC address lookup
Find the vendor and manufacturer of a device by its MAC address.
MAC address generator
Enter the quantity and prefix. MAC addresses will be generated in your chosen case (uppercase or lowercase)
IPv6 ULA generator
Generate your own local, non-routable IP addresses for your network according to RFC4193.
Math evaluator
A calculator for evaluating mathematical expressions. You can use functions like sqrt, cos, sin, abs, etc.
ETA calculator
An ETA (Estimated Time of Arrival) calculator to determine the approximate end time of a task, for example, the end time and duration of a file download.
Percentage calculator
Easily calculate percentages from a value to another value, or from a percentage to a value.
Chronometer
Monitor the duration of a thing. Basically a chronometer with simple chronometer features.
Temperature converter
Degrees temperature conversions for Kelvin, Celsius, Fahrenheit, Rankine, Delisle, Newton, Réaumur, and Rømer.
Benchmark builder
Easily compare execution time of tasks with this very simple online benchmark builder.
Lorem ipsum generator
Lorem ipsum is a placeholder text commonly used to demonstrate the visual form of a document or a typeface without relying on meaningful content
Text statistics
Get information about a text, the number of characters, the number of words, its size in bytes, ...
Emoji picker
Copy and paste emojis easily and get the unicode and code points value of each emoji.
String obfuscator
Obfuscate a string (like a secret, an IBAN, or a token) to make it shareable and identifiable without revealing its content.
Text diff
Compare two texts and see the differences between them.
Numeronym generator
A numeronym is a word where a number is used to form an abbreviation. For example, "i18n" is a numeronym of "internationalization" where 18 stands for the number of letters between the first i and the last n in the word.
ASCII Art Text Generator
Create ASCII art text with many fonts and styles.
Phone parser and formatter
Parse, validate and format phone numbers. Get information about the phone number, like the country code, type, etc.
IBAN validator and parser
Validate and parse IBAN numbers. Check if an IBAN is valid and get the country, BBAN, if it is a QR-IBAN and the IBAN friendly format.
Mortgage calculator
Calculate your monthly mortgage payment including principal, interest, taxes, and insurance (PITI) with complete amortization schedule.
Compound interest calculator
Calculate compound interest on your investments or savings with regular deposits and detailed yearly breakdown.
AdSense revenue calculator
Estimate your Google AdSense daily, monthly, and yearly revenue based on pageviews, CTR%, CPC, or RPM across various industry niches.
DevTol Architectural & Engineering Manual
DevTol is engineered as a secure, high-craft productivity workspace for software engineers, DevOps architects, sysadmins, and UI/UX designers. The core design principle governing all tools is Strictly Client-Side Execution (Zero-Server Architecture).
1. Architectural Pillars: Zero-Server Computing Mechanics
Conventional developer utilities upload your proprietary source code, private JWT tokens, database dumps, and API keys to third-party cloud servers for processing. DevTol eliminates this attack surface entirely through modern web browser primitives:
- Browser Sandboxing: All text parsing, AST generation, YAML/JSON transformations, and binary conversions execute entirely within the local V8/JavaScript engine sandbox without initiating outbound HTTP requests.
- W3C Web Crypto API: High-entropy cryptographic random generation, SHA-256 / SHA-512 hashing, HMAC calculations, and signature verification execute through native browser cryptography routines.
- Isolated Web Workers: Computationally intensive tasks such as Myers AST diffing, large XML parsing, and image quantization run inside background threads to prevent UI thread starvation.
- Offline-First PWA Execution: Service Workers cache static bundles locally on your workstation, allowing instant usage even in air-gapped or offline development environments.
2. Security & Privacy Comparison Matrix
| Engineering Metric | DevTol Client-Side Suite | Traditional Cloud Converters |
|---|---|---|
| Data Transmission | Zero (0 bytes transmitted) | Full payload uploaded over HTTP |
| Server Logging & Telemetry | Technically impossible (no backend) | Inputs recorded in access logs and CDNs |
| Regulatory Compliance (GDPR/SOC2) | 100% compliant by mathematical design | Requires Data Processing Agreements (DPA) |
| Execution Latency | Near-instantaneous local CPU speed | Network round-trip latency + queue time |
3. Engineering Standards & RFC Specifications
All algorithms implemented in DevTol strictly adhere to formal Internet Engineering Task Force (IETF) and W3C specifications:
- RFC 7519: JSON Web Token (JWT) claims verification, header decoding, and signature validation.
- RFC 4122: Universally Unique Identifier (UUID) specification for v1, v4, and namespace-hashed v5 tokens.
- RFC 4648: The Base16, Base32, Base64, and Base64URL Data Encodings.
- W3C WebP & Canvas: Lossy and lossless image transcoding algorithms designed to maximize Core Web Vitals (LCP/CLS).
4. Frequently Asked Questions (FAQ)
Q: Does DevTol send my data or code to any server?
A: Absolutely not. Every single operation runs 100% locally in your browser sandbox using JavaScript and WebAssembly. You can open your browser's Developer Tools Network Tab and verify that zero requests containing your data are ever made.
Q: Are the tools free to use, and why is no account required?
A: Yes, all tools are 100% free and open-source. Because compute execution happens on your local device CPU, there are no expensive backend compute clusters, allowing us to keep the platform free without registration barriers.
Q: How do I run DevTol completely offline?
A: DevTol is built as a Progressive Web App (PWA). Once loaded, our Service Worker caches all scripts and styles locally on your machine, enabling seamless offline usage anytime.