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.
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11 categoriesView all 373 tools (alphabetical)
JavaScript Obfuscator - Protect JS Code Online
Free online JavaScript obfuscator. Protect your JS code with variable renaming, string encryption, control flow flattening, and more. 100% private browser.
JS Formatter and Beautifier - JavaScript Code
Free online JavaScript formatter and beautifier. Beautify messy JS, minify for production, validate syntax. No signup, 100% private browser processing.
JSON Diff - Compare & Find Differences
Free JSON diff tool. Compare two JSON documents and see differences instantly. Highlights added, removed, and modified values. Side-by-side view.
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.
PopularJSON Schema Validator - Validate JSON Against Schema Online
Free online JSON Schema validator. Validate JSON data against Draft-07, 2019-09, and 2020-12 schemas. Detailed error paths, all-errors mode. No signup.
JSON to CSV Converter - Bidirectional Online Data Converter
Free JSON to CSV converter and CSV to JSON online. Flatten nested objects, auto-detect input, table preview, export file. 100% private.
PopularJSON to TypeScript Converter - Free Interface Types
Free JSON to TypeScript converter. Generate TypeScript interfaces, types, and Zod schemas from JSON. Deterministic output, no hallucination. 100% private.
JSON to XML Converter - Free Bidirectional Online Tool
Free JSON to XML converter and XML to JSON. Bidirectional with attribute handling, root element control, indentation options, syntax validation. 100%.
JSON to YAML Converter - Free Online Tool
Free JSON to YAML converter and YAML to JSON. Bidirectional with indentation control, key sorting, and syntax validation. 100% private, no upload.
JWT Decoder - Decode & Verify Tokens
Free JWT decoder. Inspect the header and claims of any token, check the expiry, and see which algorithm signed it. Nothing is transmitted.
JWT Generator - Create Signed Tokens Online
Free JWT generator. Create signed JSON Web Tokens with HS256, HS384, HS512 algorithms. No signup, no upload, 100% private browser processing.
Keyboard Tester - Test All Keys Online Free
Free online keyboard tester. Press every key to check if it works. Detect stuck keys, ghosting, and rollover. Multiple layouts, test report, no signup.
Keyword 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.
NewLive Sports Scores Tracker - NFL NBA MLB NHL Soccer
Free live sports scores tracker. Follow NFL, NBA, MLB, NHL and soccer in real time, updated every 30 seconds. No signup, no ads.
PopularLive Trending Searches - What Is Trending in Your Market
Live trending searches by country, plus the questions people actually ask about each trend. Pulled from Google and Bing on every page load.
LLM API Cost Calculator - Live Model Prices
Live LLM API cost calculator. Rank 400+ models by what your workload really costs, with prompt caching, batch discounts and long-context tiers.
Loan Calculator - Mortgage & Extra Payment Optimizer
Free loan calculator that shows more than just your payment. See how extra payments save thousands, when PMI drops, and when you pay off your home early.
Log File Merger - Merge Logs by Timestamp Online
Merge many log files into one timeline ordered by the real time of each line. Per source timezone override, correlation window and silence gaps.
NewLorem Ipsum Generator - Free Placeholder Text
Free Lorem Ipsum generator. Generate placeholder text by paragraphs, sentences, or words. Classic or randomized. No signup.
Margin Calculator - Free Profit Markup Tool
Free margin calculator. Bidirectional margin to markup, profit margin, selling price with tax layer, break-even units, multi-product. 100% private.
Markdown Editor and Preview - Live MD to HTML
Free online markdown editor with live HTML preview. Write markdown, see rendered output instantly. GitHub Flavored Markdown, syntax highlighting.
PopularMarkdown 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.
NewMath Calculator - Polynomial, Matrix, Prime Factor
Free math calculator. 6 modes: polynomial factoring, prime factorization, GCF/LCM, matrix (det/inv), quadratic formula, sequence. Step-by-step. No signup.
PopularMermaid Diagram Generator - Flowchart and Diagram
Free online Mermaid diagram generator. Create flowcharts, sequence diagrams, class diagrams, ER diagrams, Gantt charts from text. Live preview, SVG/PNG.
Meta Tag Generator - Free SEO Tool
Free SEO meta tag generator. Create title tags, meta descriptions, OG, and Twitter Cards with live SERP preview. Character counting, copy HTML. No signup.
PopularMicrophone Test - Free Online Mic Tester
Free online microphone test. Measure mic levels, detect clipping and noise, play back your voice, get a verdict and report. No signup, 100% private.
Mileage Calculator - IRS Tax Deduction Tracker Free
Free mileage calculator with IRS tax deduction tracker. Auto-handles 2026 mid-year rate. Business, medical, moving, charity. CSV export, 100% private.
Minecraft Circle Generator - Free Blueprint Tool
Free Minecraft circle generator. Draw pixel-perfect circles, ovals and domes with block counts on a live grid. PNG download, printable, no signup.
NewMock Data Generator - Free Fake Test Data Online
Free mock data generator. Generate realistic fake test data as JSON, CSV, or SQL. Presets for users, products, companies, addresses, and more. No signup.
Monitor Test - Dead Pixel & Refresh Rate Tester Online
Free online monitor test. Detect dead pixels, stuck pixels, backlight bleed, banding and ghosting. Measure your real refresh rate with full-screen.
Morse Code Translator - Encode/Decode Morse Code
Free Morse code translator. Encode text to Morse code and decode Morse back to text. Instant conversion, audio playback, and copy functionality.
Mortgage Calculator with PMI, Tax & Insurance
Free mortgage calculator with PMI, property tax, insurance, HOA. Shows true monthly payment, total cost, amortization schedule, and affordability.
PopularMouse Tester - Test Mouse Buttons Online Free
Free online mouse tester. Test every button, detect double-click chatter, scroll faults, polling rate and movement. Export a report. No signup.
Number to Words Converter - Spell Out Any Number
Free number to words converter. Spell out any number in English, including decimals and Indian lakh and crore, for checks and invoices.
Object Remover - AI Magic Eraser for Photos
Free AI object remover. Brush over unwanted people, text, watermarks, signs, blemishes and let AI fill the background. No signup, no watermark, HD output.
On This Day in History - Events and Famous Births
Discover what happened on this day in history. Major historical events, famous births, notable deaths and holidays, updated daily. No signup.
Online Chart Maker - Bar, Line, Pie & Radar
Free online chart maker. Create bar, line, pie, doughnut, radar charts with custom colors, labels, data. Export PNG. No signup, private.
Online Code Runner - Python, JavaScript, HTML
Free online code runner. Run Python, JavaScript, and HTML/CSS in your browser. Real Pyodide WASM Python, sandboxed JS Web Worker, live HTML preview.
Online Guitar Tuner - Free Mic Guitar Tuner
Free online guitar tuner. Tune by microphone with real-time pitch detection, cent-precision needle, 8 tunings plus Bass, Ukulele, Violin. 100% private.
Online Metronome - Free BPM Beat & Practice Tool
Free online metronome with tap tempo, time signatures, subdivisions, and visual beat indicator. Practice with precision timing for any instrument.
P-Value Calculator - Hypothesis Test & Z, T, Chi-Square
Free p-value calculator. Run z-test, t-test, chi-square, regression and confidence intervals. Exact p-values, step-by-step. No signup, 100% private.
Paint Calculator - Free Wall, Room & Trim Estimator
Free paint calculator. Multi-room wall area, doors and windows subtraction, 6 paint types, 5 surface textures, multi-coat, primer, ceiling, trim, waste.
Passport Photo Maker - Free Online 2x2, 35x45mm
Free passport photo maker. US 2x2, Schengen 35x45mm, India 35x35mm, China 33x48mm. Auto white background, print sheet, 100% private browser tool.
Password Generator - Create Strong Passwords
Generate strong passwords with a live strength breakdown that shows what makes them weak. Custom length, character sets and a pronounceable option. Free.
PopularPassword Strength Checker - Test Password Security
Free online password strength checker. Test password security with entropy calculation, crack time estimation, breach check via HIBP. No signup, 100%.
PDF Accessibility Checker - PDF/UA & WCAG
Audit your PDF against PDF/UA-1, WCAG 2.1 AA and Section 508: tagging, alt text, heading order, tables, forms, contrast. No upload.
NewPDF Aloud Reader - Read PDF Aloud Free
Free PDF aloud reader. Listen to any PDF read aloud with natural browser voices. Speed, pitch, page nav, bookmark. 100% private, no upload.
PDF Compare - Side-by-Side & Text Diff Comparison
Free PDF compare tool. Side-by-side visual diff with scroll sync, text diff with green/red highlights, page-by-page navigation and PDF report export.
PDF Compressor - Free Online File Size Reducer
Free PDF compressor with 4 levels (light, medium, strong, aggressive). 100% private browser processing, no upload, no signup, no watermark, no daily limit.
PopularPDF Editor - Edit, Rotate, Delete, Annotate PDF Pages
Free online PDF editor. Rotate, delete, reorder pages, add text annotations, crop, and extract pages. No upload required - works entirely in your browser.
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.