Protocol tools

Paste a digit string (spaces ignored)—pass or fail Luhn for PANs, IMEI-style IDs, and test vectors; browser-only.

Paste PAN digits—Luhn pass/fail plus Visa/Mastercard/Amex/Discover-style BIN hint; no bank lookup; browser-only.

15-digit GSM IMEI: TAC/SNR split and Luhn verification; 14-digit check hint or 16-digit IMEISV segmentation—no carrier lookup; browser-only.

14–15 hex or 18–19 decimal Mobile Equipment Identifier—Luhn mod‑10/16 check digit; RR/manufacturer/serial split—no TIA lookup; browser-only.

North American–style vehicle ID: ninth-position mod 11 checksum, WMI and sequential split—no DMV or OEM decode API; browser-only.

18–22 digit ICCID: telecom MII hint (89), E.118 / ISO 7812 Luhn on full string—no carrier or SM-DP+ lookup; browser-only.

US National Provider Identifier—10 digits, CMS Luhn on 80840 + NPI; entity type 1/2; no registry lookup; browser-only.

MOD-97-10 checksum, country length (embedded list), compact or grouped copy—no bank lookup; browser-only.

ISO 9362 layout (8 or 11 characters)—bank, country, location, branch segments; no directory lookup; browser-only.

Paste MICR routing (digits)—Fed-assignment checksum pass/fail, coarse Fed Reserve hint—ACH wires checks vary by institution.

ISBN-10 / ISBN-13 checksums and 978↔ISBN-10 conversion—book identifiers only, no title lookup; browser-only.

ISO 6166 securities ID—12 characters, letter expansion + Luhn check digit; no issuer lookup; browser-only.

North American nine-character CUSIP—issuer/issue layout and mod-10 check digit; no registry lookup; browser-only.

London seven-character SEDOL—body layout and mod-10 check digit with LSE weights; no LSEG lookup; browser-only.

Seven-digit IMO ship ID—weighted mod-10 check digit; optional IMO prefix; no registry lookup; browser-only.

Twelve-character FIGI—OpenFIGI layout and mod-10 check digit; no directory lookup; browser-only.

Twenty-character Legal Entity Identifier—ISO 17442 MOD-97-10 check digits; no GLEIF lookup; browser-only.

Nine-digit Dun & Bradstreet identifier—modulus‑10 check digit on eight data digits; no D&B lookup; browser-only.

Four-letter Market Identifier Code—ISO 10383 layout and segment hints; no MIC directory lookup; browser-only.

Split URLs into protocol, host, path, query, and hash—browser URL API; optional https:// assumption; no fetch.

Send GET/POST and other methods from your browser—see status and body; CORS limits apply.

Pull http and https links from pasted text—copy the list locally; no link checker.

Append utm_source, utm_medium, utm_campaign, and optional tags to a base URL—copy locally.

Unwrap Google, Outlook, and common redirect safe links to the real URL—parse only, no fetch.

Pick a random TCP port in a min–max range for dev configs and fixtures—local CSPRNG.

Parse a docker run command into a starter Compose service block—ports, env, volumes locally.

Press a key to inspect KeyboardEvent key, code, location, and modifier flags—browser-only.

Generate random EUI-48 MAC addresses—colon, hyphen, dotted, or plain hex—CSPRNG locally.

Convert IPv4 between dotted decimal, 32-bit integer, hex, and binary—client-side quick reference.

IPv4 or IPv6 CIDR: network, range, mask or prefix size—computed locally in your browser.

Split a parent IPv4 CIDR into equal child prefixes: every subnet listed with network, broadcast, and host bounds—capped list, local only.

Single IPv6 address: full 8-group expanded and RFC 5952 compressed text—::ffff:IPv4 mapped, not CIDR math—local only.

Normalize IEEE EUI-48 or EUI-64: colon, hyphen, dotted (Cisco-style), plain hex—and show multicast / local-admin bits—in your browser only.

Pretty-print SQL with dialect presets—pair with SQL minify on the compress page.

Headlines to SEO-friendly path segments: hyphens, diacritics, ASCII or Unicode, optional max length—local only.

Browser, OS, and device from a UA string—useful for logs and debugging.

HTTP response status reference: search 1xx–5xx, short meanings, copy status lines—client-side.

Paste HTML head or og: meta lines—see title, description, and image URL fields.

Build title, description, canonical, Open Graph, and Twitter meta tags—copy a head fragment locally.

Format GraphQL queries and mutations with readable indentation—paste one line, copy structured text locally.

Paste robots.txt or sitemap XML—see User-agent groups, rules, and URL list in your browser.

Build robots.txt with presets, Allow/Disallow paths, crawl-delay, and Sitemap lines—copy or download locally.

Build sitemap urlset XML from a URL list—optional lastmod, changefreq, priority—copy or download in the browser.

Look up common MIME types from extensions (and vice versa)—filterable table, copy Content-Type—client-side.

Compare two versions or sort a list—Semantic Versioning 2.0.0, prerelease order—client-side.

GET, POST, PUT, PATCH, DELETE—safe, idempotent, body usage—quick reference for APIs, client-side.

Common request and response header fields—names, direction, and short summaries—filterable client-side.

Well-known and common port numbers with IANA-style service names—filter by port, protocol, or keyword—client-side.

Terminal-style commands in the browser—open catalog tools with optional -q prefill; same pages as the GUI.

Owner/group/other rwx to octal, ls-style rwxrwxrwx, copy chmod, and umask 022/002 quick reference for new files and dirs—local only.

Convert dotted netmask to prefix length /n.

Expand /n prefix to dotted decimal netmask.

Hosts in an IPv4 /n network (excluding network+broadcast).

Compute network ID from IPv4 CIDR (ip/prefix).

Last address in an IPv4 subnet from CIDR.

Find IPv6 literals in logs or configs—client-side pattern scan.

Parse curl CLI snippets into method, URL, headers, and body—local best-effort helper for API debugging.

Test * and ? glob patterns against a string—local fnmatch-style check.

Convert dotted IPv4 to 32-bit unsigned integer—network math helper.

Convert a 32-bit number to dotted IPv4 notation.

Increment major, minor, or patch on a semver string—release tagging aid.

Assemble a URL from scheme, host, path, and query lines.

Lowercase host, trim, and resolve . and .. path segments.

Coerce loose version strings to semver x.y.z when possible.

Test whether two IPv4 CIDR prefixes overlap.

Parse Set-Cookie or Cookie header pairs into a table.

Split raw HTTP headers into name/value lines—local request debugging.

Extract browser, OS, and device hints from a User-Agent string.

Split MIME type and parameters from a Content-Type header value.

Parse Set-Cookie header into name, value, and attribute list.

Generate a random Sec-WebSocket-Key (16-byte Base64).

Compute Sec-WebSocket-Accept from client key + RFC magic string.

Parse RFC 7239 Forwarded header directives.

List client IPs from X-Forwarded-For comma chain.

Summarize SPF TXT record mechanisms and modifiers.

Parse DMARC TXT tag=value pairs from _dmarc records.

Parse TXT record strings from pasted dig/host output.

Extract IPv4 addresses from A record lines.

Parse priority and host from MX lines.

Look up reason phrase for numeric HTTP status.

Parse weak/strong ETag and opaque value.

Split Cache-Control directives into lines.

Parse q-weighted language tags from Accept-Language.

Extract Bearer token from Authorization header.

Parse RFC 8288 Link header relations.

Interpret Retry-After as seconds or HTTP-date.

Split Host header into hostname and port.

Parse Origin URL into scheme, host, and port.

List cache Vary tokens from comma-separated header.

Interpret Pragma and Cache-Control no-cache hints.

Parse HSTS max-age, includeSubDomains, and preload flags.

Parse Permissions-Policy allow/deny feature directives.

Explain COOP directive values.

Explain COEP credentialless/require-corp values.

Parse WWW-Authenticate challenge scheme and params.

Parse Proxy-Authenticate challenge like WWW-Authenticate.

Roughly convert a cURL command to HTTPie syntax.

Parse raw HTTP headers block to JSON map.

Validate whether a token is a standard HTTP method.

Build in-addr.arpa PTR name from IPv4 address.

Parse ws:// or wss:// URL components.

Show OUI prefix and explain vendor lookup limits.

Validate port number and show well-known service name.

Parse numbered redirect log lines into a chain list.

Suggest dig/host commands for a hostname (no live query).

Checklist for interpreting HTTP status codes on a URL.

Parse simple duration log lines to milliseconds table.

Parse notAfter date from pasted PEM metadata text.

Split Accept header into type tokens with q weights.

List charsets from Accept-Charset header.

List compression encodings from Accept-Encoding.

Split Authorization scheme and credential blob.

Split Cookie header into name=value pairs.

Split Set-Cookie attributes from response header.

Parse Location redirect URL components.

Interpret Retry-After as seconds or HTTP-date.

Parse X-RateLimit-* or RateLimit-* style headers.

Split Content-Security-Policy-Report-Only directives.

Split SPF TXT record into mechanisms.

Parse DMARC TXT tag=value pairs.

List language tags from Accept-Language header.

Parse RFC 8288 Link header relations.

Split Cache-Control directives by comma.

Split Content-Disposition type and parameters.

Explain Sec-Fetch-Site request context value.

Explain Sec-Fetch-Mode value.

Split Permissions-Policy allowlist directives.

Describe Referrer-Policy token.

Split SOA record fields from pasted text.

List Access-Control-* directives from pasted headers.

Split comma-separated client IP chain.

Interpret Age response header seconds.

Split comma-separated Via proxy hops.

Split Transfer-Encoding codings.

Parse Accept-Transfer-Encoding / TE tokens.

Parse Origin URL into scheme, host, port.

Split Host header into hostname and port.

Classify ETag as weak (W/) or strong.

Decode Basic auth header to user:pass.

Split Server response header product tokens.

Parse HTTP Date header to ISO UTC.

Parse Expires to ISO and age hint.

Parse Last-Modified to ISO timestamp.

Split If-None-Match ETag list.

Compare Content-Length to body byte size.

Split Connection hop-by-hop tokens.

List protocol upgrade tokens.

Split Cache-Control directives.

Parse ETag weak/strong and quoted value.

Parse Accept-Language with quality values.

Split Content-Type into type and params.

Parse RFC 8288 Link header relations.

Split Vary response header field names.

Parse inline/attachment and filename.

List Transfer-Encoding codings.

Split proxy chain from X-Forwarded-For.

Explain Referrer-Policy directive.

Parse Strict-Transport-Security max-age.

Split HTTP response status line into version, code, reason.

Split Host header into hostname and port.

Parse Origin URL into scheme, host, and port.

Parse Location redirect URL components.

Parse Set-Cookie into name, value, and attributes.

Interpret Age response header seconds.

Split comma-separated Via proxy hops.

Extract Bearer token from Authorization header.

Validate Content-Length byte count.

Parse HTTP Date header to ISO UTC.

Parse Allow response header methods.

Split Accept header media ranges.

List Content-Encoding codings in order.

Interpret ACAO header value.

Heuristic bot or crawler hint from UA string.

Parse Trailer header field names.

Split Warning header warn-values.

Parse Expect-CT header directives.

Parse legacy Feature-Policy directives.

Parse bytes Content-Range header.

Parse Server-Timing header metrics.

Parse RFC 7239 Forwarded header pairs.

Split CSP directives into lines.

Parse Range request header byte ranges.

Parse conditional date header to ISO UTC.

Interpret Accept-Ranges response header.

Parse Alt-Svc alternative service entries.

Parse HTTP Date header to ISO UTC.

Resolve Location redirect URL parts.

Parse legacy Pragma cache directives.

Parse Retry-After as seconds or HTTP-date.

Parse Expires HTTP-date to ISO UTC.

Parse Last-Modified to ISO UTC.

Classify ETag as weak or strong.

Split WWW-Authenticate challenges.

List Vary response header field names.

Parse Transfer-Encoding codings list.

Validate Content-Length numeric value.

Normalize X-Request-ID or Request-Id values.

List allowed HTTP methods from Allow.

Split client IP chain from header value.

Extract IP from X-Real-IP header.

Parse filename from Content-Disposition.

Extract URL from Location response header.

Split Set-Cookie name, value, and flags.

List cache Vary header tokens.

Parse q-values from Accept-Language.

Heuristic bot/crawler detection from UA.

Decode query string key/value pairs.

Build #fragment from key=value pairs.

Split User-Agent into product tokens.

Split Content-Security-Policy directives.

Parse Access-Control-* response headers.

Extract URL from Referer request header.

Normalize ETag strong vs weak values.

Split HTTP Link relation headers.

List allowed methods from Allow header.

Parse HTTP Warning header codes.

List query parameters from a URL.

Split type, subtype, and parameters.

Parse Cache-Control directive list.

Parse filename from Content-Disposition.

Parse Set-Cookie name, value, and flags.

Extract browser name from User-Agent.

List client IPs from X-Forwarded-For chain.

Parse Strict-Transport-Security max-age.

Split Vary response header values.

Parse absolute vs relative Location URL.

Parse auth scheme from WWW-Authenticate.

List compression encodings from header.

Parse Accept-Language q-values.

Explain Referrer-Policy directive.

Split Permissions-Policy directives.

Parse Access-Control-Allow-Origin and methods.

Parse Server-Timing metric list.

Parse RFC 8288 Link relations.

Interpret Retry-After seconds or HTTP-date.

Label weak vs strong ETag.

Parse HTTP Date to ISO and age hint.

Split type/subtype and parameters.

Split Cache-Control directives.

List compression encodings from header.

Parse redirect Location URL components.

Parse filename from Content-Disposition.

List HTTP methods from Allow header.

Split Vary cache key headers.

Split Content-Security-Policy directives.

Parse chunked or identity transfer encoding.

List client IPs from X-Forwarded-For chain.

Parse Expires HTTP-date to ISO and age.

Split Accept MIME types and q values.

Split language tags and q weights.

Identify server product from Server header.

Parse HTTP Date to ISO and age.

Parse Retry-After seconds or HTTP-date.

Parse auth scheme and parameters.

Split cookie name, value, and attributes.

Parse RFC 8288 Link relations.

Split Origin scheme, host, and port.

Explain Referrer-Policy directive.

Split MIME type and parameters.

Split Cache-Control directives.

List compression encodings in order.

Parse redirect Location URL parts.

Identify weak vs strong ETag.

Split Vary request-header names.

Extract browser name from User-Agent.

Split Content-Security-Policy-Report-Only directives.

Split Permissions-Policy allow lists.

Parse RFC 7239 Forwarded parameters.

Split Accept media types and q values.

Split a Set-Cookie name, value, and flags.

Split scheme and parameters from WWW-Authenticate.

Extract URI and rel from a Link header.

Interpret Retry-After as seconds or an HTTP date hint.

Show scheme and token length (does not verify JWT).

Classify an Access-Control-Allow-Origin value.

Extract type and filename from Content-Disposition.

Split Host into hostname and port.

List client IPs from an X-Forwarded-For header.

Split Accept-Language locales and q values.

Split a Cookie request header into name=value pairs.

Split Server-Timing metrics and durations.

Interpret Age header seconds and minutes.

Show Bearer scheme and token length.

Parse an Origin header into scheme, host, port.

Interpret Content-Length bytes and size hints.

Extract max-age from Strict-Transport-Security.

Parse an HTTP-Date header to ISO hint.

Extract client IP from X-Real-IP or first forwarded IP.

Split Cache-Control directives from a header value.

Split MIME type and parameters from Content-Type.

Show ETag weak flag and quoted value.

Split Link header relations and URLs.

Split Vary header field names.

Split RFC 7239 Forwarded parameters.

Parse a Referer header URL into parts.

Parse Host header into hostname and port.

Split Content-Security-Policy directives.

First token and length of a User-Agent string.

Split Accept header MIME types and q values.

Split Accept-Encoding codings and q values.

Split Accept-Language tags and q values.

Parse a Location redirect URL into parts.

Split Server-Timing metric entries.

Parse Strict-Transport-Security max-age and flags.

Split X-Forwarded-For client IP chain.

Parse Origin header scheme, host, and port.

Split Permissions-Policy directives.

Split Client Hints Sec-CH-UA brand list.

Split Cache-Control directives.

Split Content-Type MIME type and parameters.

Split Set-Cookie name, value, and attributes.

Parse a Referer header URL into parts.

Parse ETag weak/strong flag and value.

Split Content-Security-Policy directives.

Split RFC 7239 Forwarded header entries.

Split Vary header field names.

Parse Cross-Origin-Resource-Policy value.

Extract browser name hint from User-Agent.

Split Accept header MIME types and q values.

Split Authorization scheme and credentials.

Parse a Location redirect URL into parts.

Interpret Retry-After as seconds or HTTP-date.

Split WWW-Authenticate challenge parts.

Split Permissions-Policy directives.

Split X-Forwarded-For client IP chain.

Split Accept-Language locales and q values.

Split Server-Timing metric entries.

Split Client Hints Sec-CH-UA brands.

Split Accept header MIME types and q values.

Split Authorization scheme and credentials.

Parse a Location redirect URL into parts.

Interpret Retry-After as seconds or HTTP-date.

Split WWW-Authenticate challenge parts.

Split Permissions-Policy directives.

Split X-Forwarded-For client IP chain.

Split Accept-Language locales and q values.

Split Server-Timing metric entries.

Split Client Hints Sec-CH-UA brands.

Split Content-Type MIME type and parameters.

Split Cache-Control directives.

Split Content-Security-Policy directives.

Interpret ETag weak vs strong form.

Split Link header relations.

Split Cookie header name=value pairs.

Split Set-Cookie attributes.

Parse Origin header into scheme, host, port.

Split Vary header field names.

Extract browser engine hint from User-Agent.

Split Accept header media types and q-values.

Split Authorization scheme and credentials.

Split Strict-Transport-Security directives.

Parse Location redirect URL components.

Interpret Retry-After as seconds or HTTP-date.

Extract product name from Server header.

Split WWW-Authenticate challenge parameters.

Interpret Content-Length bytes and size units.

Parse HTTP Date header to ISO and Unix.

List Referrer-Policy directive tokens.

Split Accept-Language locales and q-values.

Split Content-Encoding compression tokens.

Split Permissions-Policy directives.

Split RFC 7239 Forwarded header parameters.

Split Access-Control-Allow-Origin and related CORS hints.

Split Allow header HTTP methods.

Split If-None-Match ETag values.

Parse Last-Modified header to ISO and Unix.

Extract and validate X-Request-ID trace token shape.

Split Transfer-Encoding chunked tokens.

Split User-Agent product tokens.

Split Cache-Control directives.

Split Content-Type media type and parameters.

Split Set-Cookie name=value and attributes.

Split Authorization scheme and credentials.

Parse ETag weak/strong flag and value.

Parse Location redirect URL components.

Split Server-Timing metric entries.

Split Vary header field names.

Parse HTTP Date header to ISO and Unix.

Split Accept header media types and q-values.

Split HSTS directives.

Split CSP directives.

Split Cookie header name=value pairs.

Extract Bearer token length from Authorization.

Split Link header relations.

Split Forwarded header parameters.

Parse Retry-After as seconds or HTTP-date.

Split Accept-Language locales and q-values.

Parse Last-Modified header to ISO and Unix.

Split Content-Type media type and parameters.

Split Cache-Control directives.

Extract auth scheme from Authorization header.

Split Set-Cookie header attributes.

Extract Basic auth credential length from Authorization.

Parse ETag weak/strong flag and value.

Split Server-Timing metric entries.

Parse Location redirect URL components.

Show User-Agent string length and token count.

Parse Expires header to ISO and Unix.

Split Accept header media types.

Split Content-Security-Policy directives.

Split Strict-Transport-Security directives.

Split Cookie header name=value pairs.

Extract Bearer token length from Authorization.

Split Link header relations.

Split Vary header field names.

Parse HTTP Date header to ISO and Unix.

Split Host header into hostname and port.

Parse Referer URL components.

Split Content-Type media type and parameters.

Split Cache-Control directives.

Extract Basic scheme credential length from Authorization.

Parse ETag weak/strong flag and value.

Parse Location redirect URL components.

Split Server header product tokens.

Split WWW-Authenticate challenge parameters.

Coarse browser/engine hint from User-Agent.

Split X-Forwarded-For client IP chain.

Split Allow header HTTP methods.

Split Accept header media types and q-values.

Split Accept-Language locales and q-values.

Split Set-Cookie name and attributes.

Split Cookie header name=value pairs.

Split Content-Security-Policy directives.

Parse Strict-Transport-Security max-age and flags.

Parse Referrer-Policy directive tokens.

Split Link header relation entries.

Split Vary header field names.

Parse Retry-After seconds or HTTP-date.