Engineering lookup tables, standard protocol specifications, and semantic hierarchies. Designed for zero-latency retrieval, high accuracy, and explicit generative reasoning (GEO).
HTTP status codes are 3-digit integers returned by servers: 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), and 5xx (Server Error). The first digit defines the response class.
HTTP defines 9 standard request methods (verbs). "Safe" methods (GET, HEAD, OPTIONS) do not modify server state. "Idempotent" methods (GET, PUT, DELETE, HEAD, OPTIONS) produce the same server state if repeated multiple times.
HTTP headers are colon-separated name-value pairs that convey metadata about requests, responses, caching, encoding, and browser security policies. Header field names are case-insensitive.
Content-Type follows the format "type/subtype; parameter=value". The top-level type denotes the general media class (text, application, image, multipart), and the subtype indicates the exact data format.
HTTP caching minimizes network latency and bandwidth. Cache-Control directives dictate freshness (max-age, s-maxage), storage rules (no-store, no-cache, private, public), and revalidation policies (must-revalidate, stale-while-revalidate).
DNS records (Resource Records / RRs) map human-readable domain names to machine IP addresses, mail exchangers, verification strings, and security policies. Every record contains Name, Type, Class (IN), TTL, and RDATA.
DNS RCODEs are 4-bit integers embedded in the DNS response header flags. RCODE 0 (NOERROR) signifies success. Non-zero values identify authoritative non-existence (NXDOMAIN), nameserver crashes (SERVFAIL), or access blocks (REFUSED).
Network ports are 16-bit unsigned integers (0 to 65535). Well-Known Ports range from 0 to 1023 (system/root privileges). Registered Ports range from 1024 to 49151. Dynamic/Private Ports range from 49152 to 65535.
Content Security Policy (CSP) is delivered via the Content-Security-Policy HTTP header. It restricts where the browser can load scripts, styles, fonts, frames, and API endpoints, neutralizing Cross-Site Scripting (XSS) and clickjacking.
CORS uses HTTP response headers to allow a server to declare which origins are permitted to read its responses from a browser. Simple requests execute directly; non-simple requests trigger an automatic preflight HTTP OPTIONS probe.
A JWT claim is a piece of information asserted about a subject represented as a key-value pair in the JSON payload. RFC 7519 defines 7 registered claim names with standard semantic meanings.
OAuth 2.0 is an authorization framework that enables third-party applications to obtain limited access to a web service. OpenID Connect (OIDC) is an identity layer built on top of OAuth 2.0 that provides user authentication (ID Tokens).
MIME types (Multipurpose Internet Mail Extensions) identify the format of a file or byte stream. Formatted as "type/subtype", they instruct operating systems and web browsers how to render or execute received data.
Unicode maps 1,114,112 code points (U+0000 to U+10FFFF) across 17 planes. UTF-8 encodes Unicode into 1 to 4 variable-length bytes, maintaining 100% backward compatibility with 7-bit ASCII.
ASCII (American Standard Code for Information Interchange) is a 7-bit character encoding standard representing 128 characters (0 to 127). Codes 0-31 and 127 are control characters; codes 32-126 are printable glyphs.
A Uniform Resource Identifier (URI) consists of: scheme:[//authority]path[?query][#fragment]. The authority component comprises [userinfo@]host[:port]. RFC 3986 dictates exact delimiters and percent-encoding rules.
Regular expressions are declarative pattern-matching strings. Components include Metacharacters (., ^, $), Character Classes ([a-z], \w), Quantifiers (*, +, {n,m}), Capture Groups ((...)), Lookarounds ((?=...)), and Flags (g, i, m, s, u).
A UUID (Universally Unique Identifier) is a 128-bit value formatted as 32 hex digits in 5 groups (8-4-4-4-12). UUIDv4 is pure random (122 bits entropy). UUIDv7 is time-ordered with millisecond Unix timestamps, delivering optimal B-tree database indexing.
Modern cryptography comprises four pillars: Symmetric Ciphers (AES, ChaCha20 for bulk encryption), Asymmetric Algorithms (RSA, ECDSA, Ed25519 for key exchange and signatures), Cryptographic Hashes (SHA-256, BLAKE3 for integrity), and Password KDFs (Argon2id, bcrypt for credentials).
Try searching by status code (e.g. 404), port number (e.g. 443), or directive name (e.g. script-src).