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Format, convert, generate and test. Most run in your browser; network checks and lookups say on the page what is sent.

JSON Formatter & ValidatorFormat, validate, minify and sort JSON with exact error positions Base64 Encode & DecodeText and files to Base64 and back, with URL-safe mode and image preview JWT Decoder, Verifier & EncoderDecode any JWT, verify its signature, and sign new tokens, all in your browser Password GeneratorStrong random passwords and memorable passphrases, generated on your device UUID GeneratorRandom v4 and time-ordered v7 UUIDs, up to 1,000 at once, plus a validator Unix Timestamp ConverterUnix timestamps to dates and dates to timestamps, in any time zone Hash GeneratorMD5, SHA-1, SHA-256, SHA-384 and SHA-512 of text or files, with checksum compare Regex TesterTest JavaScript regular expressions with live highlighting and a plain-English explanation Diff CheckerCompare two texts side by side and see every added and removed line JSON to TypeScriptGenerate TypeScript interfaces or types from a JSON sample CSV to JSONConvert CSV to JSON and JSON to CSV, with a table preview YAML to JSONConvert YAML to JSON and JSON to YAML, with anchors resolved Cron Expression BuilderBuild a cron schedule from menus, read it in plain English, see the next runs URL Encoder / DecoderPercent-encode or decode text and URLs, and see every part of a link SQL FormatterFormat and beautify SQL for PostgreSQL, MySQL, SQL Server and more Markdown PreviewWrite Markdown and see it rendered live, with tables, task lists and code Password Strength CheckerHow long your password would survive an attack, and exactly what makes it weak HMAC GeneratorHMAC-SHA1, SHA-256, SHA-384 and SHA-512 of text or a file, and signature checks Bcrypt Hash and VerifyHash a password with bcrypt at cost 4 to 14, or check a password against a hash TOTP Generator and TesterLive authenticator codes from a secret, a QR code for your app, and a code tester Color ConverterHEX, RGB, HSL, HWB, OKLCH and CMYK in both directions, with a contrast check Number Base ConverterBinary, octal, decimal, hex and any base to 36, exact at any size, with two's complement Slug GeneratorClean URL slugs from titles, including accented and Hindi text, one or hundreds at once HTML Formatter & MinifierIndent messy HTML, or minify it and see the bytes you saved CSS Beautifier & MinifierTidy a stylesheet or minify it, with the size saved shown JavaScript Beautifier & MinifierBeautify JavaScript, or minify it and see how many bytes went XML Formatter & ValidatorIndent XML, minify it, and see the first error by line and column JSON DiffCompare two JSON documents and list every added, removed and changed value URL Parser & Query EditorSplit a link into its parts, edit the parameters and rebuild it Data ConverterConvert JSON, YAML, XML, CSV, TSV, TOML, INI and Excel into each other Meta Tag GeneratorWrite title, description, canonical, Open Graph and Twitter tags with a live preview Open Graph PreviewPaste a page and see the share card for Facebook, LinkedIn, X, WhatsApp and Slack Robots.txt GeneratorBuild a robots.txt with presets, then check what every line really does Sitemap GeneratorTurn a list of URLs into a valid sitemap.xml, with an index when it gets too big UTM BuilderBuild campaign links with source, medium and campaign, then export the lot as CSV Keyword Density and ReadabilityWord and phrase counts, densities, reading time and a Flesch readability score HTTP Status CodesEvery HTTP status code, what it means, when to send it and the RFC it comes from MIME TypesExtension to MIME type and back, with magic bytes and the header to send User-Agent ParserRead a user-agent string: browser, engine, OS, device type and whether it is a bot curl ConverterTurn a curl command into fetch, Node, Python, PowerShell or HTTPie code Barcode GeneratorMake EAN-13, EAN-8, UPC-A, Code 128, Code 39 and ITF-14 barcodes as SVG or PNG Mock Data GeneratorRows of realistic test data as JSON, CSV, SQL or XML, the same every time from one seed Certificate DecoderRead an SSL certificate, CSR or public key: names, dates, key size and fingerprints Roman Numeral ConverterNumbers to Roman numerals and back, with a check that says why a numeral is wrong Subnet CalculatorIPv4 and IPv6 CIDR: network, broadcast, host range, mask, wildcard and subnet splits Excel Column Letter ConverterExcel column letters to numbers and back (A=1, AA=27, XFD=16384), one or a whole list Excel Date Serial ConverterExcel serial numbers such as 45292 to dates and back, 1900 or 1904 system, with times Chmod CalculatorLinux file permissions: tick boxes or type 755 or rwxr-xr-x, copy the chmod command JSONPath TesterRun RFC 9535 JSONPath queries on pasted JSON and see every match highlighted Invisible Character DetectorFind zero-width spaces, odd spaces, bidi controls and lookalike letters, then clean them DNS LookupAny DNS record for a domain, or all common types at once, with TTLs and decoded fields MX LookupMail servers of a domain by priority, with addresses, and whether it can receive email Reverse DNS LookupFind the host name of an IP address and check that it points back (FCrDNS)ASN LookupFind the network (AS number, owner, prefix and country) behind an IP address DNS Propagation CheckerCompare one DNS record at Cloudflare and Google side by side, with DNSSEC on and off SPF CheckerCheck an SPF record, expand every include and count DNS lookups against the limit of 10 DMARC CheckerCheck a DMARC record and read its policy, alignment and report addresses in plain words DKIM CheckerLook up a DKIM key by selector and see its type, real key length and any problems BIMI LookupCheck a BIMI record, its logo and certificate links, and whether DMARC is strict enough MTA-STS and TLS-RPT CheckerCheck the MTA-STS and TLS-RPT records that make mail to your domain travel encrypted DNSSEC CheckerCheck DNSSEC for a domain: keys, the DS at the parent, signature expiry and the AD verdict Blacklist CheckerCheck a mail server IP against spam blocklists, and see which lists a browser cannot check WHOIS LookupDomain and IP registration from the registry over RDAP: registrar, expiry date and status Email Header AnalyzerPaste raw email headers: every hop with its delay, sender IPs, SPF, DKIM and DMARC results IMEI CheckerCheck an IMEI number’s check digit, see its TAC and serial, and look up the phone model What Is My IP AddressSee the public IP address websites see for your connection, IPv4 or IPv6, and copy it WebRTC Leak TestSee which IP addresses WebRTC hands to websites, and whether your VPN is being bypassed Browser and Device InfoSee what any website can read about your browser and device, and copy it for support Email Address ValidatorCheck an email address’s syntax and whether its domain can receive mail, one or a list Link Safety CheckerPaste a suspicious link and see the phishing tricks in it, without ever opening the link Domain Health CheckOne report on a domain’s mail servers, SPF, DMARC, DKIM, DNSSEC and blocklists India ID Number ValidatorCheck a GSTIN, PAN, Aadhaar, IFSC, UPI ID or PIN code for format and check digit Ping TestPing a host or IP from our server: 4 replies with min, average and max time Traceroute OnlineTrace the route from our server to a host: every router hop with its times, up to 20 Port CheckerCheck whether one TCP port is open on a public host or IP, from outside your network SSL CheckerCheck a website's live SSL certificate: expiry, names, issuer, chain and TLS version HTTP Headers CheckerSee the status, response headers and redirect chain of any URL, with security checks SMTP TestTest a domain's mail server on port 25: greeting, EHLO features and STARTTLS certificate Is It DownCheck if a website is down for everyone or just you, with status code and response time Title Tag and Meta Description CheckerTitle and meta description length in characters and pixels, and where Google cuts them Morse Code TranslatorText to Morse code and back, with sound at an adjustable speed, using the ITU code table URL ShortenerTurn a long link into a short one with a QR code, free and without an account Test Credit Card NumbersSandbox card numbers from Stripe and Razorpay with expiry and CVV, and a Luhn checker HTML Entity Encoder & DecoderEncode &, <, > and quotes as HTML entities, or decode every named and numeric entity Text to Binary ConverterTurn text into binary, hex, decimal or octal bytes, and decode them back, in UTF-8 String Escape & UnescapeEscape text for a JSON, JavaScript, Java, Python, SQL or CSV string, or unescape it .htaccess Redirect GeneratorPaste old and new URLs and get 301 rules for .htaccess or Nginx, checked for loops JSON Schema ValidatorValidate JSON against a JSON Schema (2020-12, 2019-09, draft 7), with each error located Semver CheckerTest versions against an npm range such as ^1.2.3, sort them and see the next version .env File ValidatorCheck a .env file line by line as dotenv reads it, and convert it to JSON or YAML Regex EscapeEscape text so a regex matches it literally in JavaScript, Python, PHP, Java, Go or .NET Docker Run to Compose ConverterTurn docker run commands into a compose.yaml: ports, volumes, networks, health checks CSP EvaluatorCheck a Content-Security-Policy directive by directive and see how scripts get past it .gitignore GeneratorBuild a .gitignore from 61 templates for languages, frameworks, editors and systems Dockerfile LinterCheck a Dockerfile against 55 hadolint rules: pinned versions, root user, cache and more Conventional Commit CheckerCheck a commit message against Conventional Commits and commitlint, with its version bump package.json ValidatorCheck a package.json the way npm reads it: name, version, license, dependencies and syntax License GeneratorMake a LICENSE file: MIT, Apache 2.0, GPL 3.0 and 20 more, with your name and year JWK to PEM ConverterConvert a JSON Web Key to PEM and back for RSA, EC and Ed25519 keys, with the thumbprint JSON to Go Struct ConverterTurn a JSON sample into Go structs with json tags, int or float64, pointers and omitempty Markdown Table GeneratorPaste cells from Excel, Google Sheets or CSV and get a lined-up Markdown table, or back Base32 and Base58 Encoder and DecoderEncode or decode Base32 (RFC 4648, hex, Crockford) and Base58 for text or hex bytes HTTP/2 and HTTP/3 CheckerTest whether a website supports HTTP/2 and advertises HTTP/3 (QUIC) in its Alt-Svc header IBAN Validator and CheckerCheck IBANs from 89 countries: length, format and mod-97 check digits, with the bank code IPv6 Readiness CheckerIs a domain ready for IPv6? AAAA records for its website, mail servers and name servers JSON to C# Class ConverterTurn a JSON sample into C# classes or records for System.Text.Json or Newtonsoft.Json JSON to Java Class ConverterTurn a JSON sample into Java POJOs, records or Lombok classes annotated for Jackson JSON to Kotlin Data Class ConverterTurn a JSON sample into Kotlin data classes for kotlinx.serialization, Gson or Moshi JSON to Python Class ConverterTurn a JSON sample into Python dataclasses, Pydantic models or TypedDicts with type hints JSON to Rust Struct ConverterTurn a JSON sample into Rust structs with serde derives, renames, Option and Vec JSONL Viewer and ValidatorCheck JSON Lines and NDJSON line by line, view records as a table, convert to a JSON array Mixed Content CheckerFind the http scripts, styles, images and forms that break the padlock on an https page Open Graph CheckerCheck the live Open Graph and Twitter card tags of any URL and see what is missing Robots.txt CheckerCheck a live robots.txt for errors and test whether a URL is blocked for Googlebot Security.txt CheckerCheck a website's security.txt against RFC 9116: Contact, Expires, location and signature Sitemap CheckerCheck a live sitemap.xml: URL count, lastmod dates, size limits and protocol errors TLS Version CheckerSee which TLS versions a server accepts, 1.0 to 1.3, and whether weak ciphers are still on CSS Box Shadow GeneratorBuild a layered CSS box-shadow with a live preview, or paste one and edit it CSS Clamp GeneratorTurn a size at a phone width and a size at a desktop width into one fluid clamp() value CSS Gradient GeneratorBuild linear, radial and conic CSS gradients with a live preview, or paste one to edit CSS Specificity CalculatorSee the (A, B, C) specificity of any selector, part by part, and which rule wins Hex Viewer (xxd online)See any file as an xxd hex dump with offsets and text, or turn a hex dump back into a file htpasswd GeneratorMake a user:password line for Apache or nginx basic auth, in bcrypt, apr1 or SHA-512 JMESPath TesterRun JMESPath queries on pasted JSON, as the AWS and Azure CLI --query does JSON Patch Generator and TesterCreate an RFC 6902 JSON Patch from two documents, or apply one and see the result JSON to SQL ConverterJSON to CREATE TABLE and INSERT statements for PostgreSQL, MySQL, SQLite or SQL Server MAC Address ConverterRewrite a MAC in any format, read its bits, and get its EUI-64 and IPv6 link-local address Security Headers GeneratorChoose HSTS, CSP, framing and more, then copy the nginx, Apache or Vercel config Set-Cookie Header AnalyzerSee what a browser keeps from each Set-Cookie line, what it rejects and how to harden it SQL to JSON ConverterTurn SQL INSERT statements or a database dump into JSON or CSV, table by table SRI Hash GeneratorMake the integrity hash and script or link tag for a CDN file, or check one SSH Key FingerprintGet the SHA256 and MD5 fingerprint of an SSH public key, as ssh-keygen -l shows it systemd OnCalendar TesterCheck a systemd timer OnCalendar= value and see its next run times, or convert cron JSON to ZodPaste a JSON sample and get a Zod schema with its z.infer type, ready to copy GraphQL FormatterFormat, minify and validate GraphQL queries and schemas, with errors by line and column OpenAPI Viewer and ValidatorPaste or drop an OpenAPI or Swagger file: see every endpoint by tag and every broken $ref Nginx Config GeneratorA commented nginx server block for a reverse proxy, static site, SPA or redirect PX to REM ConverterConvert px to rem or em and back, or turn every px in a stylesheet into rem CSS Grid GeneratorBuild a CSS grid with column sizes, gaps and named areas, live preview, CSS or Tailwind CSS Flexbox GeneratorSet direction, wrap, justify, align and gap on a live flex row, then copy CSS or Tailwind CSS Border Radius GeneratorRound each corner with sliders, elliptical corners and blob shapes, shortest CSS to copy Glassmorphism CSS GeneratorFrosted glass CSS with backdrop-filter, the Safari prefix, a fallback and a contrast check HTML to JSX ConverterPaste HTML and get JSX React accepts: className, style objects, closed tags, camelCase

Not sure which tool you need?

JSON ToolsFormat, validate and convert JSON, YAML, CSV and TypeScript Code Formatters and MinifiersBeautify or minify JavaScript, CSS, HTML, SQL, XML and JSON, and see the bytes Security Tools for DevelopersHashes, HMACs, bcrypt, JWTs and one-time codes, worked out on your own machine SEO ToolsTags, sitemaps, robots.txt, share cards and campaign links, checked before they ship Debug and InspectRead a regex, a diff, a status code, a user agent or a URL and find what is wrong Developer ConvertersTimestamps, number bases, colours, cron lines, encodings and curl commands, read both ways Test Data GeneratorsRows, test cards, placeholder images, sized files, IDs and text that are safe to use in any test

Guides for these tools

How to check an IMEI number, and what the check can and cannot proveAn IMEI has 15 digits: an 8-digit TAC, a 6-digit serial and 1 Luhn check digit. Work the check by hand, and see why it cannot show a phone is stolen.
How to check whether a card number is valid, and what valid does not meanThe Luhn check worked on 4242 4242 4242 4242: the digits total 80, ending in 0, so it passes. Plus scheme and length checks, and why valid is not real.
Test data that cannot reach a real person, built safe on purposeWhy fixtures use example.com, RFC 5737 IP ranges, gateway test cards and seeds, and the one gap: a random Indian phone number may belong to someone.
How a TOTP code comes from a setup key and the time, worked through step by stepA 2FA code is HMAC-SHA1 of the setup key and the 30-second step, cut to 6 digits. The RFC 6238 test key at 59 seconds gives 287082, worked out here.
What your user agent says about you, and what it gets wrongA user-agent string names 5 things: browser, engine, OS, device and bot. Read Chrome on Windows part by part, and why it cannot tell Windows 10 from 11.
DNS leak test - what a browser can check, and how to check the rest in one commandA browser page cannot see which DNS server your device asks. How to find it with one nslookup command, and the IP and WebRTC checks that go with it.
How to check SPF, DKIM and DMARC for a domain, and fix the common faultsWhat SPF, DKIM and DMARC each prove, how to look them up, the 10-lookup SPF limit, Gmail's bulk-sender rules, and rolling DMARC from none to reject.
How to decode a JWT and check whether it is validA JWT is three Base64URL parts. How to read the header and claims, check exp, nbf, iss and aud, verify the signature, and why decoding is not verifying.
How to convert JSON to CSV, and CSV back to JSON, without losing dataHow nested JSON becomes CSV columns, what happens to arrays, why Excel mangles IDs and long numbers, and how to turn a CSV back into JSON safely.
How to open a Markdown (.md) file, read it formatted, and turn it into HTMLA .md file is plain text with formatting marks. How to open one on Windows, Mac or a phone, see it formatted, and convert Markdown to HTML or PDF.
How to read a Unix timestamp, in seconds or milliseconds, in your time zoneA Unix timestamp counts seconds from 1 January 1970 UTC. How to tell seconds from milliseconds by the digits, convert to IST or any zone, and avoid 2038.

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JSON Formatter & Validator
Base64 Encode & Decode
JWT Decoder, Verifier & Encoder
Password Generator
UUID Generator
Unix Timestamp Converter

Money

SIP Calculator
EMI Calculator
GST Calculator
FD Calculator
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Lumpsum Calculator

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Guides Questions About How we check Law library (beta)PrivacyTerms Disclosure Contact More: Exam practice (UGC NET Paper 1)Most tools run in your browser; a tool that uses a server says so on its page. © 2026 Omnikit (theomnikit.com)