Developer tools that work.
373 free utilities for code formatting, file conversion, online calculators, AI assistance, and more. No signup, no upload, no tracking.
Popular Tools
8 most-usedFree AI Chat - No Login, No Signup
Free AI chat powered by Groq and NVIDIA models. No login, no signup, no tracking. Coding, writing, math, brainstorming. Conversations stay in your browser.
Audio 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.
Condom Size Calculator - Find Your Exact Fit
Free condom size calculator. Enter girth and length in mm, cm or inches to get your nominal width range and a fit verdict for any condom. 100% private.
Free Online Calculator - Scientific, Percent, BMI & Loan
More than a phone keypad: scientific functions, percent, loan payments and BMI in metric and imperial units. Free to use, no signup.
Free Email Signature Generator - Outlook Gmail HTML
Free email signature generator. 10 table-based templates, MSO compatible, base64 photo embedding, click-to-call phones, social icons. 100% private.
Image Compressor - Reduce Image File Size Online Free
Free online image compressor. Reduce image file size without losing quality. Supports JPG, PNG, WebP. No upload, privacy-first processing.
Image Cropper - Crop Photos with Aspect Ratio
Free online image cropper. Crop with aspect ratio presets, rotate, flip and zoom. Social media sizes for Instagram, Facebook and Twitter. No upload.
JSON Formatter - Format & Validate JSON
Free JSON formatter. Format, minify and beautify JSON, convert to and from YAML, and get the exact line of any syntax error. 100% browser, no upload.
Recently Updated
6 toolsCSS Specificity Calculator - Compute Selector Weight
Free CSS specificity calculator. Compute a,b,c values for any selector instantly. Understand selector weight and cascade priority. No signup.
NewHeart Rate Zone Calculator - 5 Zones by Age
Free heart rate zone calculator. Enter your age to get all five training zones in bpm, compare four max HR formulas, and find your personal Zone 2 range.
AI Code Reviewer - Free Online Code Review
Free AI code reviewer. Paste code, get instant review for bugs, performance, security, and best practices. No login, private.
NewPDF to Text Extractor - Free Online PDF Text Reader
Free PDF to text extractor. Extract plain text from any PDF in your browser. No upload, no signup, 100% private. Copy or download results.
NewMarkdown to PDF Converter - Free Online MD to PDF
Free online MD to PDF converter. Convert markdown to PDF instantly in browser. Preserve formatting, headings, code blocks, tables. No signup, 100% private.
NewKeyword Suggestions Generator - Free SEO Keyword Research
Free keyword suggestions from Google and Bing autosuggest. Expand one seed into 20 live search ideas, compare both engines, and copy the list. No signup.
NewBrowse by Category
11 categoriesView all 373 tools (alphabetical)
2FA 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.
AES 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 - Months, Days, Birthday & Countdown
Free age calculator. Your exact age in years, months, days, hours and minutes, plus the next birthday countdown and milestone dates.
Age Calculator by Photo - How Old Do I Look? Free AI
Free AI age calculator by photo. Detect how old you look in any picture or live camera, with multi-face and expression handling. 100% private, no signup.
PopularAI Code Reviewer - Free Online Code Review
Free AI code reviewer. Paste code, get instant review for bugs, performance, security, and best practices. No login, private.
NewAI Crawler Checker - 19 AI Bots, GPTBot & robots.txt
Free AI crawler checker. Audit robots.txt against 19 AI bots and validate llms.txt, and see the exact rule that blocks GPTBot.
AI Crawler Log Analyzer - Bot Traffic
Free AI crawler log analyzer. Drop an Apache, nginx, IIS or Cloudflare log: GPTBot, ClaudeBot and PerplexityBot hits, status codes, spoof checks.
NewAI Detector - Check If Text Is AI Generated
Free AI content detector using multi-model voting (Groq, Gemini, NVIDIA). Detect ChatGPT, Claude, Gemini text with sentence highlighting. No signup.
AI 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.
AI 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.
PopularAI Image to Video Generator - Animate Photos
Free AI image to video generator. Animate photos into AI videos with Agnes AI. No signup, no watermark, no daily limit. Image to video in minutes.
AI 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.
AI Video Script Generator - Shorts & Social Videos
Free AI video script generator. Write YouTube Shorts, TikTok and Reels scripts with proven hooks, retention beats and CTA. No signup.
NewAI Writing Coach - Essay & Content Feedback
Free AI writing coach for essays and content. Get rubric-based feedback on thesis, structure, evidence, clarity and voice. Keeps your voice, no signup.
NewAir 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.
Area Calculator - Square Feet for Rooms & Walls
Room, floor and wall areas in square feet and square meters, plus paint gallons, wallpaper rolls and carpet yards. Free, no signup.
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.
Audio 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.
PopularAudio 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.
PopularAudio 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.
PopularAuto 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.
Binary 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.
PopularBirthday 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 Pressure Calculator - Average & Stage
Free blood pressure calculator. Average a batch of readings, see your ACC/AHA stage, MAP and pulse pressure, plus a private log with 7 and 30 day averages.
NewBlood 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.
Body 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 & Macro Calculator - BMR, TDEE & Goals
Free calorie calculator. Your BMR, TDEE and macro split for weight loss, maintenance or muscle gain, using Mifflin-St Jeor.
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.
NewFrequently Asked Questions
Are all 373 developer tools really free?
Yes — every tool on DevTools Hub is 100% free with no signup, no trial, no daily limit, and no watermark. The site is supported by optional cloud functions and ad-free by design.
Do you upload my data to a server?
Most tools process everything in your browser. Only AI-backed tools (AI Chat, AI Detector, Image Generator, Story Animator, Translator, Paraphrasing Tool, Plagiarism Checker, Resume Builder, Cover Letter Generator, Citation Generator, ATS Resume Checker, AI Humanizer, Text-to-Speech, Text-to-Video, Text Summarizer, Math Solver, Grammar Checker, Subtitle Generator, and a few others) call a server API for GPU compute. Uploads are transient and never logged. Each tool page documents exactly what leaves your device.
Why use these tools instead of asking an AI chatbot?
AI chatbots hallucinate exact arithmetic, produce invalid JSON/XML, drop SVG attributes, and cannot compute dates, fractions, or compound interest reliably. DevTools Hub uses deterministic code — same input always yields the same verified output.
Do I need to create an account?
No account, no email, no tracking cookies. Open any tool, use it, close the tab. Your inputs never leave your browser unless you explicitly call a cloud-backed AI tool.
How often are new tools added?
New tools ship 2-3 times per week. The homepage shows a 373 tool count that updates automatically as new entries are added to the public manifest. See the sitemap.xml for the complete list.
Can I use these tools commercially?
Yes. The outputs you generate belong to you — use them in client work, internal tools, or commercial products without attribution. The tool code itself is MIT-licensed on GitHub.