# ILSERBY

> Converters, generators, DNS/SSL/IP utilities — fast, free, no account. Client-side tools run in the browser; network lookups use live public data with cached landing pages.

Use the links below for indexed tool and network landing pages. Permalink result URLs (e.g. `/whois/example.com`, `/ip/1.2.3.4`) are share-only and excluded from search indexes.

- [Home](https://ilserby.net/): full catalog and popular workflows
- [Network hub](https://ilserby.net/network): DNS, WHOIS, SSL, IP, proxy, and email authentication checks
- [Sitemap](https://ilserby.net/sitemap.xml): all indexed landing URLs with hreflang alternates

## Network & checks

- [WHOIS Lookup](https://ilserby.net/whois): Domain and IP registration via RDAP with WHOIS fallback.
- [DNS Lookup](https://ilserby.net/dns): DNS records table, propagation, DNSSEC, and CAA checks.
- [Email Authentication](https://ilserby.net/email-auth): SPF, DMARC, DKIM, and MX validation.
- [Mail Server Health](https://ilserby.net/mail-health): MX host IPs, reverse DNS, FCrDNS, blocklists, plus SPF/DMARC summary.
- [IP Lookup](https://ilserby.net/ip): IP geolocation, reverse DNS, ASN, and RDAP registration.
- [IP Blacklist Check](https://ilserby.net/ip-blacklist): Multi-list spam and abuse blacklist check for an IP.
- [Bulk IP Geolocation](https://ilserby.net/bulk-ip): Batch IP geolocation and ASN lookup.
- [Bulk Blacklist Check](https://ilserby.net/bulk-blacklist): Batch IP blacklist screening.
- [WebRTC Leak Test](https://ilserby.net/webrtc-leak): Browser WebRTC leak test (client-side).
- [Proxy Checker](https://ilserby.net/proxy-check): HTTP/SOCKS proxy exit IP and latency check.
- [Proxy Anonymity](https://ilserby.net/proxy-anonymity): Proxy anonymity level and header leak analysis.
- [SSL Test](https://ilserby.net/ssl): Certificate expiry, chain trust, hostname match, and CT hostnames.
- [HTTP Headers](https://ilserby.net/headers): HTTP redirect chain, security headers, robots.txt, and sitemap hints.
- [Lookalike Domains](https://ilserby.net/lookalike): Typosquat and lookalike domain comparison.

## DevOps & infrastructure

- [Cron Expression Generator](https://ilserby.net/cron-generator): Cron expression generator with presets and plain-language schedule summary. For crontab, GitLab CI, and CronJob. Free.
- [IPv4 Subnet Calculator](https://ilserby.net/subnet-calculator): IPv4 subnet calculator from CIDR — network, broadcast, host range, mask, and wildcard. For firewall and VPC rules. Free.
- [Unix Timestamp Converter](https://ilserby.net/unix-timestamp): Unix timestamp converter — epoch seconds or milliseconds to ISO dates and back. One-click Now button. Free online tool.
- [CIDR Overlap & Contains Checker](https://ilserby.net/cidr-overlap): CIDR overlap checker — see if subnets collide or if an IP falls inside a block. For VPC peering and routes. Free tool.
- [SemVer Calculator](https://ilserby.net/semver-calculator): SemVer validator and calculator — compare versions, bump major/minor/patch, check npm-style strings. Free in browser.
- [SLA & Uptime Calculator](https://ilserby.net/sla-calculator): SLA and uptime calculator — allowed downtime from 99.9% or custom targets. Per day, month, and year. Free SRE tool.
- [.env File Parser](https://ilserby.net/env-parser): .env file parser — dotenv key/value table with duplicates and syntax issues flagged. Review before deploy. Free, local.
- [Proxy List Format Converter](https://ilserby.net/proxy-format): Proxy list format converter — HTTP, SOCKS, auth@host, colon-auth, JSON lines. Up to 5,000 lines. Free in browser.
- [Nginx ↔ .htaccess Converter](https://ilserby.net/nginx-htaccess): Convert nginx rewrite rules to Apache .htaccess and back. Redirects, try_files, front controllers. Free converter.
- [Self-Signed Certificate Generator](https://ilserby.net/cert-generator): Self-signed SSL certificate generator — RSA key and PEM cert with SAN DNS names for local dev. Download files. Free.
- [OpenSSH Public Key Inspector](https://ilserby.net/ssh-key-inspector): OpenSSH public key inspector — SHA256 and MD5 fingerprints, authorized_keys multi-line parse. Free online tool.
- [Regex Tester & Replacer](https://ilserby.net/regex-tester): Regex tester with live matches, capture groups, highlighted hits, and replace preview. DevOps presets. Free in browser.

## Encode & decode

- [Base64 Encode / Decode](https://ilserby.net/base64-encode): Encode or decode Base64 online — standard and URL-safe RFC 4648. Text stays in your browser, nothing uploaded. Free Base64 tool.
- [URL Encode / Decode](https://ilserby.net/url-encode): URL encode and decode with percent-encoding for query strings and paths. Component or full URI mode. Free online encoder.
- [Hex Encode / Decode](https://ilserby.net/hex-encode-decode): Hex encode and decode UTF-8 text — byte dumps for protocols, HMAC debug, and certs. Free encoder, runs locally.
- [HTML Entities Encode / Decode](https://ilserby.net/html-entities): HTML entity encoder and decoder — escape <, >, &, and quotes for XSS-safe snippets and CMS content. Free online tool.
- [Unicode Escape Encode / Decode](https://ilserby.net/unicode-escape): Unicode escape encoder — \uXXXX for JavaScript, JSON, and i18n. Brace form for astral emoji. Free online converter.
- [Punycode / IDNA Converter](https://ilserby.net/punycode-idna): Punycode and IDNA converter — Unicode domains to xn-- ASCII and back with per-label breakdown. Free online tool.
- [Charset & Code Point Viewer](https://ilserby.net/charset-viewer): UTF-8 code point viewer — graphemes, hex bytes, and UTF-16 units per character. For encoding bugs and i18n QA. Free.
- [Quoted-Printable Encode / Decode](https://ilserby.net/quoted-printable): Quoted-Printable encode and decode for MIME email bodies and headers. Optional 76-column wrap. Free online tool.
- [JWT Decoder](https://ilserby.net/jwt-decoder): JWT decoder — inspect header, payload, exp, and claims with human-readable dates. Signature not verified. Free debug tool.
- [HMAC Generator](https://ilserby.net/hmac-generator): HMAC SHA-256, SHA-384, and SHA-512 generator for webhooks, Stripe, GitHub, and API auth. Secret stays local. Free.
- [Hash Generator (SHA-256 / SHA-1 / MD5)](https://ilserby.net/hash-generator): SHA-256, SHA-1, and MD5 hash generator — updates as you type, input never uploaded. Free online hashing tool.

## Marketing & SEO

- [UTM Link Builder](https://ilserby.net/utm-builder): UTM link builder — campaign URL with utm_source, medium, campaign, term, and content for analytics. Free marketing tool.
- [Meta Title & Description Length Checker](https://ilserby.net/meta-length): Check meta title and description length for Google snippets. Character counts and SERP-style preview. Free checker.
- [Open Graph & Twitter Card Meta Generator](https://ilserby.net/og-meta): Open Graph and Twitter Card meta generator — og: and twitter: tags for Facebook, LinkedIn, and X previews. Free SEO tool.
- [Canonical Link Tag Generator](https://ilserby.net/canonical-tag): Generate rel=canonical link tag for duplicate URLs and SEO consolidation. Paste URL, copy one HTML line. Free generator.
- [Hreflang Alternate Tags Generator](https://ilserby.net/hreflang-tags): Hreflang alternate link tag generator for multilingual SEO. Locale rows, optional x-default, copy HTML block. Free.
- [Meta Robots Tag Generator](https://ilserby.net/meta-robots): Meta robots tag generator — noindex, nofollow, nosnippet, max-snippet, and Google-specific directives. Free SEO tool.
- [JSON-LD Structured Data Generator](https://ilserby.net/json-ld): Schema.org JSON-LD generator for WebPage, Article, SoftwareApplication, and Organization. Copy valid script block. Free.
- [FAQPage JSON-LD Generator](https://ilserby.net/faq-schema): FAQPage JSON-LD generator — unlimited Q&A pairs for Schema.org rich results. Copy embeddable script tag. Free online.
- [BreadcrumbList JSON-LD Generator](https://ilserby.net/breadcrumb-schema): BreadcrumbList JSON-LD generator — ordered name and URL crumbs for SERP breadcrumbs. Copy script tag. Free.
- [XML Sitemap Generator](https://ilserby.net/sitemap-xml): XML sitemap generator from a URL list for Google Search Console. changefreq, priority, download or copy. Free tool.
- [Keyword Density Analyzer](https://ilserby.net/keyword-density): Keyword density analyzer — top words and 2–3 word n-grams with stop-word filtering. Text stays local. Free SEO tool.
- [robots.txt Generator](https://ilserby.net/robots-generator): robots.txt generator — user-agent groups, allow/disallow paths, and sitemap URL. Download or copy file. Free online.
- [WCAG Contrast Checker](https://ilserby.net/contrast-checker): WCAG contrast checker — foreground and background ratio with AA and AAA pass indicators. Live preview. Free a11y tool.

## Convert & format

- [JSON ↔ YAML Converter](https://ilserby.net/json-yaml): Convert JSON to YAML and back for Kubernetes, CI, and configs. Live preview with one-click copy. Free online converter — no signup.
- [CSV ↔ JSON Converter](https://ilserby.net/csv-json): Convert CSV to JSON and JSON to CSV with comma, semicolon, or tab delimiter. Spreadsheet-friendly row objects. Free, runs in browser.
- [Markdown ↔ HTML Converter](https://ilserby.net/markdown-html): Markdown to HTML with live preview, or HTML snippets back to Markdown. For READMEs, docs, and CMS. Free online converter.
- [JSON ↔ XML Converter](https://ilserby.net/json-xml): Convert JSON to XML and XML to JSON for APIs and legacy systems. Nested maps and repeated elements. Free converter in browser.
- [TOML ↔ JSON Converter](https://ilserby.net/toml-json): TOML to JSON and JSON to TOML for Cargo, pyproject, and config files. Clear parse errors on invalid syntax. Free online tool.
- [JSON Formatter & Validator](https://ilserby.net/json-formatter): JSON formatter, minifier, and validator — pretty-print with indent or compress to one line. Free, instant results in browser.
- [Java Properties ↔ JSON](https://ilserby.net/properties-json): Java .properties to JSON and back for Spring and JVM configs. Comments and escape sequences handled. Free online converter.
- [Bits, Bytes & Bandwidth Converter](https://ilserby.net/data-units): Convert bytes, MB, Mbps, GiB, and transfer rates — SI and IEC side by side plus download time estimates. Free bandwidth calculator.
- [Slugify Text](https://ilserby.net/slugify): Slugify titles into lowercase hyphenated URL-safe permalinks for blog posts, CMS routes, and filenames. Free, instant copy.

## Random & generators

- [UUID Generator](https://ilserby.net/uuid-generator): Generate random UUID v4 GUIDs — one or up to 100, lowercase or uppercase, copy or download .txt. Free in browser.
- [Password Generator](https://ilserby.net/password-generator): Strong password generator with length, charset toggles, and ambiguous-symbol exclusion. Crypto-local. Free secure tool.
- [Random Number Generator](https://ilserby.net/number-random): Random number generator — integers or decimals in a range, bulk count, optional unique values. Copy or download. Free.
- [Random Name Generator](https://ilserby.net/name-generator): Random name generator by country — fake first and last names for QA, demos, and database seeds. Free online tool.
- [Random Email Generator](https://ilserby.net/email-generator): Random email generator for form tests and demos — safe example domains, not for real mail. Bulk copy. Free QA tool.
- [Fake Data Generator](https://ilserby.net/fake-data): Fake data generator — full profiles with name, email, phone, and address by country. Export JSON, CSV, or text. Free.
- [Lorem Ipsum Generator](https://ilserby.net/lorem-ipsum): Lorem ipsum generator — paragraphs, sentences, words, or bullet lists for wireframes and layout tests. Free placeholder text.

## Other tools

- [Browser & Device Fingerprint](https://ilserby.net/fingerprint): Browser fingerprint test — canvas, WebGL, WebRTC, fonts, and a composite SHA-256 ID. Runs locally, nothing uploaded. Free privacy check.

## DevOps extras

- [Locale Atlas](https://ilserby.net/locale): DevOps utility on ILSERBY.

## Optional

- [Locale atlas](https://ilserby.net/locale): BCP 47 locale reference pages for developers.
- [Credits](https://ilserby.net/credits): Software and data source attributions.
- [Privacy policy](https://ilserby.net/privacy): How ILSERBY handles visitor data.
- [Terms of use](https://ilserby.net/terms): Site terms.
- [Cookie policy](https://ilserby.net/cookies): Cookie usage.
- [Contact](https://ilserby.net/contact): Contact form.