Free online tools — no install, no sign-up
Developer, text, image, conversion, calculator, website and gaming tools that work the moment the page opens. Most tools run in your browser, so your data never leaves your device.
- 100% free
- No account needed
- Most tools keep data in your browser
- Results as you type
Popular tools
- JSON Formatter Beautify, minify and validate JSON with error line numbers.
- QR Code Generator Turn a URL or text into a QR code PNG.
- Image Converter Batch convert to WebP, JPG or PNG and compress.
- Steam Price History Paste a Steam URL to see the current and lowest price.
- Regex Tester Test regular expressions live with highlighted matches.
- Unix Timestamp Converter Convert epoch timestamps to dates and back, any time zone.
- Gacha Probability Calculator Chance to pull a character in N pulls, with pity and 50/50.
- Loan Calculator Monthly payment, total interest and amortization schedule.
Developer Tools
Format data, test regex, decode tokens.
- JSON Formatter Beautify, minify and validate JSON with error line numbers.
- YAML Formatter Validate and format YAML, convert YAML ⇄ JSON.
- XML Formatter Pretty-print, minify and validate XML.
- Regex Tester Test regular expressions live with highlighted matches.
- JWT Decoder Decode a JWT header, payload and expiry.
- Base64 Encode & Decode Convert text to and from Base64, UTF-8 and URL-safe.
- Password Generator Generate strong random passwords with custom length.
- Cron Expression Generator Explain a cron schedule and list its next run times.
- SQL Formatter Beautify SQL queries with uppercase keywords and indented subqueries.
Text Tools
Count words, convert case, compare text.
- Word Counter Count words, characters, paragraphs and reading time.
- Case Converter UPPER, lower, Title Case, camelCase, snake_case and more.
- Text Diff Checker Compare two texts line by line and see changes.
- Remove Duplicate Lines Delete duplicate and empty lines, optionally sort.
- Markdown Previewer Write Markdown and see it rendered live.
- Markdown Table Generator Paste from Excel or CSV and get a Markdown table.
Converters
JSON ⇄ CSV, colors, timestamps.
- JSON to CSV Converter Turn a JSON array into a CSV for Excel.
- CSV to JSON Converter Turn CSV or Excel data into a JSON array.
- Markdown to HTML Converter Convert Markdown into clean HTML source.
- URL Encode & Decode Percent-encode and decode URLs and parameters.
- Color Converter HEX, RGB, HSL, CMYK conversion and contrast check.
- Unix Timestamp Converter Convert epoch timestamps to dates and back, any time zone.
Image Tools
Convert images, create QR codes.
- Image Converter Batch convert to WebP, JPG or PNG and compress.
- QR Code Generator Turn a URL or text into a QR code PNG.
- Image Resizer Batch resize images by width, height or percent.
- EXIF Remover Remove GPS location and camera data from photos — no quality loss.
- Favicon Generator Make favicon.ico, every icon size and the HTML from one image.
Calculators
Percentages, age, business days.
Website Checkers
Meta, OG, redirect, header and SSL checks.
- Meta Tag Checker Audit title, description, canonical and other SEO tags.
- Open Graph Checker Preview link cards on Facebook, X, LinkedIn and Discord.
- Redirect Checker Trace 301 / 302 redirect chains to the final URL.
- HTTP Header Checker Inspect response, caching and security headers.
- SSL Certificate Checker Check SSL expiry, issuer and covered domains.
- Robots.txt Generator Create robots.txt and optionally block AI training bots.
- UTM Builder Build campaign URLs with UTM parameters for GA4.
Gaming & Anime Tools
Steam price history and lowest price.
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About Otaku Dojo Tools
Otaku Dojo Tools is a collection of free online utilities that turn everyday tasks — formatting JSON, converting images, generating QR codes, checking SSL certificates, finding a Steam game's historical lowest price — into three steps: open, paste, done.
Every tool works the same way: input on the left, live result on the right, with Copy, Download and Sample buttons in the same place. Only checkers that must reach another website (such as the redirect and HTTP header checkers) go through our server; everything else runs in your browser.
FAQ
Are the tools really free?
Yes. Every tool is free to use with no account or login. The site is supported by ads.
Is the data I paste uploaded or stored?
Formatters, converters, calculators and image tools run entirely in your browser — nothing is sent to a server. Only the website checkers (meta tags, Open Graph, redirects, HTTP headers, SSL, Steam price history) send the URL you enter to our server so it can connect for you, and queries are not stored.
Do the tools work on mobile?
Yes. All tools work in mobile and tablet browsers, and the layout stacks vertically on small screens.
Which languages are supported?
English, Traditional Chinese and Japanese. Switch languages from the top-right corner of any page.
Can I request a new tool?
Yes. Tell us what you need on the Contact page and we will consider it for the roadmap.