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)
SIP Calculator - Free Mutual Fund Returns
Free SIP calculator. Estimate mutual fund maturity from monthly investment, return and tenure. Goal, step-up and lumpsum modes. 100% private, no signup.
Sitemap Audit - Sitemap Errors & Noindex
Free sitemap audit. Finds the errors Google reports: 404s, redirects, noindex pages, blocked URLs, bad lastmod, duplicates. Gets you a clean sitemap.xml.
NewSize Converter - Shoe, Ring & Apparel Sizes
Free online size converter for shoe, ring, bra, clothing. 9-country systems + sister-size bra calculator. ISO 9407 + 8655. 100% private.
PopularSleep Calculator - Optimal Bedtime & Wake Up Time
Free sleep calculator. Find your ideal bedtime or wake-up time based on 90-minute sleep cycles. Wake up refreshed, not groggy. No signup, 100% private.
Slug Generator - Create SEO-Friendly URL Slugs Online
Free slug generator. Convert text to SEO-friendly URL slugs with custom separators, stop word removal, max length, and bulk mode. Real-time preview.
Snake Game - Classic Snake Online Free
Play the classic Snake game online free. Control your snake, eat food, grow longer. Multiple speeds, grid sizes, wall wrap mode. No ads, no signup.
Snow Day Calculator - School Closure Chance
Free snow day calculator. Turns live hourly weather data into a school closure probability for your ZIP, postal code or city. No signup.
NewSolar Sizing Calculator
Free solar sizing calculator. Estimate solar panel array size and battery storage from monthly kWh use and peak sun hours. Private browser math, no signup.
NewSolitaire - Free Classic Klondike Card Game Online
Play free Klondike Solitaire online. Classic card game with undo, hint, draw 1 or 3. No signup, no ads, 100% free in your browser.
Song Lyrics Finder - Free Lyrics Search No Signup
Free online song lyrics finder. Search by artist and title. No signup, no ads, no tracking. 100% private. AI cannot retrieve copyrighted lyrics - we do.
PopularSpace Keeper - Keep HuggingFace Spaces Awake
Free tool to keep your HuggingFace Spaces awake and prevent idle timeout. Supports multiple access methods, uptime monitor, custom intervals (1-48 hours).
Speaker Test - Free Online Speaker Tester
Free online speaker test. Check left/right channels, 20Hz-20kHz frequency sweep, stereo balance and polarity. 100% private, no upload.
Speech Time Calculator - Words to Minutes and Time
Free speech time calculator. Convert words to minutes and seconds at standard speaking rates (100-238 wpm). Paste text, set WPM, add pauses. No signup.
Spin the Wheel - Random Picker & Name Wheel
Free spin the wheel random picker. Add names, decisions or prizes, spin for a fair random winner with weighted odds, sound and CSV export. No signup.
SQL Formatter - Format & Beautify SQL
Free SQL formatter. Beautify queries with correct indentation for MySQL, PostgreSQL, SQLite and SQL Server, and catch unbalanced syntax. No signup.
SSL Certificate Checker - Test Website Security
Free SSL checker. Scan any website for TLS security and certificate validity. Get grade A+ to F. No signup. AI cannot test real SSL certificates.
Statistics Calculator - Mean, Median & SD
Free statistics calculator. Compute mean, median, mode, standard deviation, variance, quartiles and z-scores step by step. No signup, 100% private.
Stopwatch - Free Online Stopwatch with Lap Times
Free online stopwatch with millisecond precision, lap/split timing, lap statistics, CSV export, and fullscreen mode. No signup, no ads. Works offline.
Study Planner - Exam Schedule Generator
Free study planner. Add subjects with priority, set exam date, get 7-day schedule with subject rotation, Pomodoro breaks, iCal export. No signup.
Subnet Calculator - IPv4 IPv6 CIDR VLSM Supernetting
Free subnet calculator for IPv4 and IPv6. Bit-exact CIDR, VLSM, supernetting, overlap detection. No signup. AI cannot reliably compute subnets - we do.
PopularSubtitle Editor - Free Online SRT & VTT Editor
Free online subtitle editor. Edit, fix and convert SRT and VTT files in your browser. Batch shift timing, validate overlaps, split long cues.
PopularSubtitle Generator - Free AI Audio/Video to SRT & VTT
Free AI subtitle generator. Convert audio or video to SRT or VTT with Whisper large-v3 timestamps. 18 languages, no signup, no watermark.
Sunrise Sunset Calculator - Find Sunrise & Sunset Times
Free sunrise and sunset calculator for any city. Today, tomorrow or any date, plus golden hour, twilight and day length. Works offline, no signup.
SVG Optimizer - Free Online SVG Minifier & Cleaner
Free online SVG optimizer. Clean, minify and compress SVG files. Remove metadata, comments, empty groups, editor data. No upload, 100% private browser.
SVG to JSX Converter - Free React Component Generator
Convert SVG to React JSX component online free. Paste SVG code, get clean React/TypeScript components with camelCase attributes, forwardRef, memo. 100%.
SVG to PNG Converter - Free Online SVG Rasterizer
Convert SVG to PNG free online. Rasterize vector graphics to PNG, JPG, WebP with custom dimensions, scale control, background color. 100% browser-based.
Table of Contents Generator - Free TOC Maker for MD HTML TXT
Free table of contents generator. Extract headings from Markdown, HTML, or plain text and export a structured TOC as Markdown, HTML, JSON, or YAML.
TDEE Calculator - BMR, Macro, Protein, Water, 1RM
Free TDEE calculator. 6 modes in one: BMR (3 formulas), macro split (5 diets), protein target, water intake, and 1 rep max. kg/lb toggle. No signup.
Text Cleaner - Remove Line Breaks, Spaces & HTML Tags
Free online text cleaner. Remove line breaks, extra spaces, HTML tags, duplicate lines, and clean messy text with 20+ deterministic options. No signup.
Text Summarizer - Condense Articles & Papers
Free online text summarizer. Condense articles, papers, and long text into key points. Extractive mode (private, no upload) or AI abstractive mode.
Text to EPUB Converter - Free Online TXT MD HTML to eBook
Free text to EPUB converter. Turn text, Markdown, or HTML into EPUB 3.0 eBooks in your browser. Custom cover, TOC, 40+ languages. AI cannot make EPUB.
Text to Handwriting - Free Online Handwritten Text Generator
Free text to handwriting converter. Turn typed text into realistic handwritten notes on lined, grid or plain paper. 18 fonts, 7 ink colors, PNG/JPG/PDF.
PopularText to Speech - Free Online Voice Generator
Free online text to speech with 8 AI voices. Convert text to natural-sounding audio in English and Chinese. No signup required. Browser TTS and AI-powered.
Time Calculator - Add, Subtract Hours, Minutes & Seconds
Time between two times, add or subtract hours and minutes, convert hours to decimal and sum several periods. Overnight rollover, breaks, free.
Timestamp Converter - Unix Time Conversion
Convert Unix timestamps to dates and dates back to timestamps, in seconds, milliseconds or ISO 8601. The current time ticks live. No signup required.
Tone Generator - Play Audio Frequency Notes
Free online tone generator. Play any audio frequency from 1 Hz to 20,000 Hz as pure waves, see the note name, or download a WAV. No signup.
Unit Converter - Length, Weight, Temperature and More
Free online unit converter. Convert between length, weight, temperature, volume, speed, area, data, time, and pressure units instantly. No signup required.
URL Encoder/Decoder - Encode URLs Safely
Free URL encoder and decoder. Percent-encode special characters or decode them back, with a live character reference and one-click copy. No signup.
URL Metadata Extractor - Link Preview and Meta Tags
Free URL metadata extractor and link preview tool. Extract OG tags, Twitter cards, JSON-LD, SEO meta, and headings from any URL. See how your link looks.
PopularUser Agent Parser - Browser OS Device Detection Online
Free online User Agent parser. Identify browser, OS, device, and bot from any UA string. Detect Googlebot, GPTBot. 100% private, no upload.
UTM Builder - Free Campaign URL Generator with Presets
Free UTM builder. Generate campaign tracking URLs with platform presets for Google Ads, Facebook, LinkedIn, and more. Auto-format, parameter breakdown.
UUID Generator - UUID v1 v4 v7 Generator
Generate UUID v1, v4 and v7 identifiers, single or in bulk up to 100 at a time. Uppercase, hyphen and no-hyphen formats. Private, free, no signup.
Video Compressor - Hit Any Size Target
Free online video compressor. Hit an exact target size, 10 MB for Discord or 25 MB for email. No upload, no watermark. Runs fully in your browser.
Video Cutter - Trim & Cut Video Online Free
Free online video cutter. Trim, cut, and split MP4, WebM, MOV video files in your browser. No upload, 100% private. Powered by FFmpeg.wasm.
Video to Audio Converter - Extract MP3 from Video Free
Free online video to audio converter. Extract MP3 audio from MP4, WebM, MOV, AVI files. No upload, 100% private, in-browser processing.
Video to GIF Converter - Free Online MP4 to GIF Maker
Free online video to GIF converter. Convert MP4, WebM and MOV to animated GIFs with custom FPS, resolution and trim. No upload, 100% private.
PopularVIN Decoder - Free VIN Check Digit Validator & Lookup
Free VIN decoder and check digit validator. Verify ISO 3779 check digits, decode model year, and look up specs from the NHTSA database. 100% private.
Virtual Piano - Play Online Keyboard Free
Free virtual piano you can play right in your browser. Use your computer keyboard or mouse, record and download WAV, follow along with 6 songs.
Vocal Remover - Remove Vocals from Songs Free
Free online vocal remover. Strip vocals from any song to make karaoke or instrumental versions. MP3, WAV, M4A, OGG, FLAC. 100% private, no upload.
Voice Changer - Free Online Audio Voice Effects
Free voice changer with 10 presets (chipmunk, deep, robot, alien, female, male, old, telephone). Custom pitch and speed. 100% private, no upload.
PopularFrequently 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.