All 358 Free Online Developer Tools
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11 categoriesAll Tools
Alphabetical2FA Authenticator - TOTP Generator & Decoder
Decode otpauth QR codes and URIs, generate TOTP and HOTP codes, and find out why your authenticator code is rejected. Nothing is uploaded.
NewAES Encrypt Decrypt - Secure Text Online
Free AES-256-GCM encryption tool. Encrypt text with a password using PBKDF2 and Web Crypto, or decrypt it. Runs in your browser, nothing is uploaded.
Age Calculator - Years, Months, Days & Birthday
Free age calculator. Calculate your exact age in years, months, days, hours. See next birthday countdown and milestone dates. No signup required.
AI Crawler Access Checker - GPTBot
Free AI crawler access checker. Audit robots.txt against 19 AI bots and validate llms.txt to spec. See the exact rule that blocks GPTBot. No signup.
NewAI Crawler Log Analyzer - GPTBot & ClaudeBot Traffic
Free AI crawler log analyzer. Drop an Apache, nginx, IIS or Cloudflare log: GPTBot, ClaudeBot and PerplexityBot hits, status codes, spoof checks.
NewAI Email Writer - Free Reply Generator
Free AI email writer and reply generator. 15 email types, 6 tones, 3 lengths, 12 languages. Subject lines included. No signup.
AI Essay Writer - Free Academic Essay Generator
Free AI essay writer for 9 types, 4 levels, 5 citation styles. Outline + thesis + draft modes, editable, downloadable. No signup, no word limit.
NewAI Image Generator - Free Unlimited Image Creation
Free AI image generator. Create unlimited images with GPT Image 2, Nano Banana, FLUX.1 Schnell and Seedream. No API key, no watermark, no daily limit.
NewAI Letter Generator - 8 Types Free
Free AI letter generator for 8 real situations: thank-you, cover, apology, invitation, resignation, recommendation, complaint, congratulations.
AI Plagiarism Checker - Content Originality Test
Free AI plagiarism checker that searches the web for duplicate content. Get similarity percentage, source URLs, and suggestions. No signup required.
AI Social Media Post Generator - Free Multi-Platform
Free AI social media post generator. One input, 5 platform-optimized posts: Twitter, LinkedIn, Instagram, Facebook, TikTok. No signup, no limits, 100%.
AI Story Animator - Novel to Video with Agnes AI
Free AI story animator. Input a novel chapter, get a full storyboard with images, videos, and narration. Powered by Agnes AI multi-modal API.
AI Video Generator - Text to Video Free
Free AI video generator. Turn text prompts into videos online with Agnes AI. No signup, no watermark, no daily limit. Text to video in minutes.
Air Quality Index Checker - Live AQI Today
Free air quality index checker. Live AQI for any city or your location, a pollutant breakdown, and the cleanest hour to go outside. No signup.
NewAnagram Solver & Word Unscrambler - Free
Free anagram solver. Enter letters (use ? for blanks) to find every valid word from a 168K-word dictionary with Scrabble scores. No signup.
APCA Contrast Checker - WCAG 3 Lc Calculator
Free APCA contrast checker for WCAG 3. Get the Lc value, the minimum Lc your font size and weight need, the WCAG 2.1 ratio, and a passing color fix.
NewArea Calculator - Square Footage and Room Areas
Free area calculator for rectangle, triangle, circle, trapezoid, L-shape rooms, multi-room aggregation. Wall area with door/window subtraction. Paint.
ASCII Art Generator - Image and Text to ASCII
Free ASCII art generator. Convert any image or text into ASCII art with 5 fonts, adjustable width and custom characters. PNG & TXT download, 100%.
Aspect Ratio Calculator - Free Online Tool
Free aspect ratio calculator. Calculate aspect ratio from width and height, find missing dimensions, visual preview of 16:9, 4:3, 21:9 ratios. Social.
Astronomy Calendar - Moon Phases & Meteor Showers
Free astronomy calendar with daily moon phases, sun rise/set, upcoming meteor showers, eclipses, and planetary events. Pure browser-based calculations.
NewAudio Cutter & Trimmer
Free online audio cutter and trimmer. Cut and trim MP3, WAV, M4A, FLAC, OGG with waveform precision. No upload, 100% private.
Audio Denoiser - Reduce Background Noise Free
Free audio denoiser browser tool. Remove background noise, hiss, hum, wind and ambient sound from MP3, WAV, M4A, FLAC, OGG files. 100% private, no upload.
Audio Editor - Free Online Audio Effects & Editing Tool
Free online audio editor. Cut, fade, normalize, change speed/pitch, add reverb and echo, EQ bass/treble, reverse, trim silence. 100% private, no upload.
Audio File Transcriber - MP3 to Text Converter
Free online audio file transcriber. Convert MP3, WAV, M4A, OGG, FLAC, AAC, MP4, MOV, AVI to text with AI Whisper. Timestamps, SRT/VTT export, 25 languages.
Audio Joiner & MP3 Merger - Merge Audio Files Free
Free online audio joiner. Merge MP3, WAV, M4A, FLAC and OGG into one with drag-to-reorder, crossfade or silence gap modes. No upload, 100% private.
NewAudio to Text Converter - Free Online Speech to Text
Free online audio to text converter. Convert speech to text in real-time with browser-based voice recognition. No uploads, no sign-up, 100% private.
Auto Loan Calculator - Free Car Payment Calculator
Free auto loan calculator. Calculate monthly car payments with tax, trade-in, down payment. Compare loan terms, total interest, amortization. No signup.
Baby Percentile Calculator
Baby Percentile Calculator on WHO growth curves. Weight, length and head circumference percentiles with z-scores, charts and corrected age for preemies.
NewBackground Remover - Remove Image Background Free Online
Free online background remover tool. Remove image backgrounds automatically. No signup. Works with JPG, PNG, WebP. Fast and private.
Barcode Generator - QR, UPC, EAN and Code 128
Free online barcode generator. Create QR codes, UPC, EAN, Code 128, Code 39 and more. Download as PNG/SVG. No signup required, 100% free.
Barcode Scanner - Decode EAN, UPC, Code 128, QR Codes
Free online barcode scanner. Decode EAN-13, UPC-A, Code 128, Code 39, QR codes and 15+ formats from images or camera. 100% private, no upload, no signup.
Base64 Encoder/Decoder - Encode Data
Free Base64 encoder and decoder. Encode text to Base64 and decode back. Works entirely in your browser with no upload and no signup. 100% private.
Base64 to Image Converter - Convert Base64 String to Image
Convert base64 strings and data URIs to viewable images. Supports PNG, JPG, WebP, GIF, BMP. 100% private, browser-based, no upload required.
NewBinary Hex Converter - Binary to Decimal, HEX, ASCII
Free online binary hex converter. Convert between binary, decimal, hex, and ASCII text. Instant conversion, no upload needed. Developer tool for encoding.
Bingo Card Generator - Free Printable
Free printable bingo card generator. 1-75, 1-90, or custom themed. 100% free, no signup, no watermark, no upload. AI cannot generate cards - we do.
NewBirthday Wishes Generator - Free Personalized Messages
Free birthday wishes generator. 30+ recipient types, 6 tones, 4 output formats, multi-language. AI gives generic wishes - we personalize them. No signup.
Blood Type Calculator - Child Blood Type
Free blood type calculator. Works from blood type labels with real genotype uncertainty, not a guess. Punnett square, reverse inference, PNG, CSV export.
NewBody Fat Calculator - Navy, YMCA & BMI Free
Free body fat calculator: US Navy, YMCA, BMI and Jackson-Pollock methods. Fat mass, lean mass, healthy ranges and target weight. Private, no signup.
BTU Calculator - Free AC and Heating BTU Estimator
Free BTU calculator. Compute room heat load for AC and heating with ceiling, sun, insulation, climate, occupancy and kitchen factors. Convert to tons.
Business Card Maker - Free Printable Card Designer
Free business card maker. Design cards with 5 templates, custom fonts, PNG/PDF/vCard export. No signup, 100% private. AI cannot make 300 DPI print files.
Caffeine Calculator - Half-Life Sleep Tracker
Free caffeine calculator. Personalized half-life, when to stop drinking coffee, multi-drink tracker, daily budget. NHS pregnancy safe. 100% private.
Calorie Calculator - TDEE & BMR Macro Calculator
Free calorie calculator. Calculate your TDEE, BMR, and optimal macros for weight loss, maintenance, or muscle gain. Mifflin-St Jeor equation, no signup.
Chain-of-Thought Prompt Generator
Free chain-of-thought prompt generator. Build zero-shot, few-shot and structured CoT prompts for any task from cited research. Runs in your browser.
NewChess Move Validator - Free Legal Move Checker Online
Free chess move validator. Play chess on an interactive board with real-time legal move validation. No signup. Perfect for learning chess rules.
NewClick Speed Test - CPS & Reaction Time
Free click speed test (CPS) and reaction tester. Measure clicks per second over 1-100 seconds, right-click, spacebar or touch. No signup, 100% private.
Code Minifier & Beautifier - JS, CSS, HTML
Free online code minifier and beautifier. Minify JS, CSS, HTML for production or beautify for debugging. Size stats, copy, all in browser. No signup.
NewCode to Image Converter - Create Beautiful Code Screenshots
Convert your source code into stunning syntax-highlighted PNG images. Choose from 7 themes, customize padding & fonts, and share beautiful code.
Color Blindness Simulator - CVD Test
Free color blindness simulator. Test how images and colors appear with 8 types of color vision deficiency (protanopia, deuteranopia, tritanopia). WCAG.
Color Contrast Checker - WCAG AA AAA
Free WCAG color contrast checker. Check if text and background colors meet AA and AAA accessibility standards. Real-time contrast ratio, pass/fail.
Color Palette Generator - Create Harmonious Color Schemes
Free color palette generator. Create harmonious schemes with 7 harmony rules. Export as CSS, Tailwind, SCSS, JSON. Lock colors, WCAG checker. No signup.
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