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)
PDF Form Filler - Fill Out PDF Forms Online Free
Free PDF form filler. Fill out any PDF form online. Text fields, checkboxes, radio buttons, dropdowns. 100% private browser processing, no upload.
PDF Merger - Combine Multiple PDFs into One
Free online PDF merger. Combine multiple PDF files into one with drag-drop reordering, visual preview, and compression. No upload limit. Works in browser.
PDF OCR - Free Online Scanned PDF to Searchable PDF
Free PDF OCR. Convert scanned PDFs to searchable PDFs in your browser. Tesseract.js + pdf-lib. 13 languages, 150-300 DPI. No upload, 100% private.
PopularPDF Page Numbers - Add Page Numbers to PDF Free Online
Free PDF page number adder. Add page numbers to any PDF - Arabic or Roman format, 9 positions, custom prefix, skip cover. 100% private, no upload.
PDF Redactor - Permanently Redact PDF Online Free
Free PDF redactor. Permanently redact text from PDFs - search words, draw boxes, auto-detect emails, phones, credit cards. 100% private, no upload.
PDF Signer - Sign PDF Online Free Electronic Signature
Free online PDF signer. Draw your electronic signature on any PDF — contracts, agreements, NDAs. 100% private browser processing, no upload, no signup.
PDF to Excel Converter - Free Online PDF to XLSX
Free online PDF to Excel converter. Extract tables and data from PDF to XLSX. 100% private, no upload, no signup, unlimited conversions.
PDF to Image Converter - Free Online JPG PNG WebP
Free PDF to image converter. Convert PDF pages to JPG, PNG or WebP with DPI (72-300), quality and page range controls. Preview thumbnails. 100% private.
PopularPDF 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.
NewPDF to Word Converter - Free DOCX Online
Free PDF to Word converter. Extract text from PDF to editable DOCX, RTF or TXT. 100% private browser processing, no upload, no signup, no watermark.
PopularPDF Unlocker - Remove Password Protection Free Online
Free online PDF unlocker. Remove password protection from PDF files in your browser. No upload, no signup, no daily limits. 100% private, AES-256.
PDF Watermark - Add Text Watermark to PDF Free Online
Free online PDF watermark tool. Add CONFIDENTIAL, DRAFT, or custom text watermarks to any PDF. 100% private browser processing, no upload, no signup.
Percentage Calculator - Find %, Increase, Decrease
Free percentage calculator online. Calculate X% of Y, increase/decrease, reverse percentage, and add/subtract percent. Instant results, no signup.
Photo Collage Maker - Free Image Combiner
Free photo collage maker. Combine multiple images into collages with 8 layout templates, custom spacing, background, border radius.
Photo Editor - Free Online Image Editor No Signup
Free online photo editor. Crop, rotate, adjust brightness, contrast, saturation. Apply filters, add text, draw, resize. No signup, no upload, 100% private.
Photo to Anime Converter - Free Online AI Anime Filter
Free photo to anime converter. Turn any photo into anime, cartoon, comic, pop art, pixel art or watercolor with 6 art styles. 100% private browser.
Photo to Pencil Sketch Converter - Free Online Sketch Effect
Free photo to pencil sketch converter. Turn any photo into a realistic pencil sketch, charcoal, ink or line art with 5 art styles and live controls. 100%.
Ping Test - Latency, Jitter & Packet Loss
Free online ping test. Measure latency, jitter and packet loss to any host from your browser. See if lag is your connection or the server. No signup.
Poker Odds Calculator - Texas Hold'em Equity
Free poker odds calculator. Exact hand-vs-hand equity by full enumeration, not Monte Carlo. Board cards, up to 3 players, call/fold helper. No signup.
Pomodoro Timer - Free Online Focus Timer with Tasks
Free Pomodoro timer with task tracking. 25/5 focus sessions you can configure, break reminders, daily statistics and a streak counter. No account, no ads.
Port Checker - Test Open Ports Online Free
Free port checker. Test up to 25 TCP ports from outside your network and get open, closed or filtered with latency, no signup.
NewPowerPoint to PDF Converter - Free PPTX to PDF Online
Convert PPTX slides to PDF right in your browser. Text stays selectable and searchable. Batch conversion, optional speaker notes, no upload and no signup.
NewPrayer Times Calculator - Salah Countdown & Qibla
Salah times for your exact coordinates with a next-prayer countdown, six calculation methods, Hanafi Asr option, and Qibla bearing. 100% in your browser.
NewPrintable Calendar Generator - Free PDF
Free printable calendar generator. Monthly or yearly calendars with US federal holidays, week numbers and Monday-Sunday start. Print-ready PDF, no signup.
Printer Test Page - Print Quality Diagnostic
Free printer test page. Print color, CMYK, nozzle, banding, alignment and text sharpness test sheets to diagnose HP, Epson, Canon & Brother printers.
Product Description Generator - Amazon, eBay, Etsy Free
Free AI product description generator. One input, 5 platform-optimized descriptions for Amazon, eBay, Etsy, Shopify, Walmart. SEO keywords, JSON-LD.
Proxy Checker - Free IP Proxy Detection Tool
Free online proxy checker. Detect if an IP address is a proxy, VPN, or Tor exit node. Check IP geolocation, WHOIS, and open proxy ports.
PTO Calculator - Accrual & Balance
Free PTO calculator. Project your paid time off balance on any date from your pay schedule, accrual cap and carry-over limit, and estimate a payout.
NewQR Code Generator - Create QR Codes Free
Free QR code generator for URLs, text, WiFi logins, email, SMS and vCards. Download as PNG or SVG at any size. No signup, no watermark, no daily limit.
PopularQR Code Reader - Decode QR Codes from Image & Camera
Free online QR code reader. Decode QR codes from images, screenshots or a live camera. Extract URLs, WiFi passwords and vCards. 100% private, no signup.
PopularRandom Generator - Numbers, Dice, Coins, Decisions
Free online random generator: random numbers, dice rolls, coin flips, wheel spins and decisions. True randomness via the crypto API. No signup.
Readability Score Calculator Online
Free readability calculator. 6 formulas: Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, ARI. Grade level + sentence highlighting.
Receipt Generator - Free Online Receipt Maker
Free online receipt generator. Create professional receipts with auto-calculated tax, discount, multi-currency, line items, and PDF download. 100%.
Recipe Converter - Free Scale & Convert Recipes Online
Free recipe converter. Scale any recipe up or down, convert metric to US cups, convert cups to grams with real ingredient densities. 80+ ingredients.
ReDoS Checker - Regex Denial of Service
Find catastrophic backtracking in any regex. Static shape analysis plus a measured growth curve in a Web Worker, and the attack string that triggers it.
Regex Tester - Test Regular Expressions
Test regular expressions against your own text with live highlighting. Supports the g, i, m, s, u and y flags, shows every match and capture group.
Rent vs Buy Calculator - Find Your Break-even Year
Free rent vs buy calculator. Break-even year, year-by-year net worth comparison, PMI, and selling costs, with a sensitivity table. No signup.
NewResistor Color Code Calculator - 4 & 5 Band
Free resistor color code calculator. Read 3, 4, 5 and 6 band resistors to value, tolerance and TCR. Reverse a value into bands and E24/E96 values.
REST API Tester - Free Online HTTP Client
Free online REST API tester and HTTP client. Send GET, POST, PUT, PATCH, DELETE requests with custom headers and body. View response status, headers.
Retirement Calculator - 401k IRA Nest Egg
Free retirement calculator. Project nest egg with employer match and inflation. Required corpus, 4 percent rule, Social Security break-even 62/67/70.
Roman Numeral Converter - Free Online Number Tool
Free Roman numeral converter. Convert numbers to Roman numerals and back, including dates. Supports 1-3,999,999 with overline notation. No signup.
Roofing Calculator - Pitch Squares Shingle Bundles Free
Free roofing calculator. True roof area from pitch multiplier (1/12 to 18/12), squares, shingle bundles, underlayment, starter strip, ridge cap, drip edge.
Running Pace Calculator - Pace, Time and Distance
Free running pace calculator. Calculate pace, time, or distance for any race. Generate splits, predict race times with Riegel formula, convert pace units.
Salary Calculator - Free Online Hourly to Annual Converter
Free salary calculator. Convert hourly to annual, monthly, biweekly, weekly pay instantly. Calculate overtime and unpaid time adjustments. No signup, 100%.
Schema Markup Generator - Free JSON-LD Structured Data Tool
Free online Schema Markup Generator. Create valid JSON-LD structured data for Article, Product, FAQ, LocalBusiness, Organization, and more. No signup.
Screenshot Tool - Annotate and Edit Screenshots
Free online screenshot annotation tool. Upload images to annotate with arrows, text, rectangles, circles and blur. Download or copy with no watermarks.
Seating Chart Maker - Free Printable Seating Plan
Free seating chart maker for classrooms and weddings. Assign seats with keep-apart and keep-together rules, drag to adjust, then print or save PNG.
NewSemVer Conflict Solver - npm Version Range Checker
Check whether npm semver ranges resolve together. Finds the conflicting constraints, shows what each range allows, and names the newest published match.
SEO Checker - Free Website Audit With Fixes You Can Paste
Free SEO checker. Reads one page the way a crawler would: indexability, robots.txt, 19 AI crawlers, JSON-LD, meta tags, and the tag to paste for each fix.
NewSignature Maker - Sign PDF Online Free
Free signature maker. Draw, type, or upload your signature, then place it on any PDF and download. No signup, no watermark, 100% private.
Frequently 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.