RSS Feed Validator

Purpose & User Intent: The Online RSS Feed Validator is a domain-focused diagnostic tool for developers, publishers, content managers, and automation workflows that rely on RSS for distribution. It accepts a feed URL or raw XML and assesses validity against XML well-formedness and RSS specification requirements, helping ensure feeds render correctly in readers and aggregators. Users run validations during publishing, CI checks, and CMS migrations to catch structural issues early.
Core Logic & Features: Core capabilities include syntactic validation (well-formed XML), RSS version conformance checks, and detection of missing required elements (e.g., channel, title, link for RSS 2.0). Additional features include encoding detection, diagnostics by error type, and version-aware checks for common extensions. Required features cover input parsing, XML parsing, and error reporting with line/column references when available. Optional/advanced capabilities include support for Atom and RSS extensions, configurable version targets, and export of results to JSON/CSV.
Inputs & Outputs: Inputs include feed_url (string, URL) or raw_xml (string) with required flag on at least one. Outputs include is_valid (boolean), errors (array of objects with location, code, message), warnings (array), detected_version (string), encoding (string), and validated_at (timestamp). For URL validation, the tool also reports reachability state. In raw XML mode, it provides a parsed summary including root element and major RSS elements present.
Algorithms & Calculations: The tool uses an XML parser to verify well-formedness, then applies a rule set derived from RSS versions (2.0, 1.0/RSS-like, Atom adapters if enabled). It classifies issues by severity, suggests fixes, and may attempt basic namespace resolution to validate common extensions.
Error & Edge Cases: Handles invalid URLs, timeouts, large feeds via streaming parsing, and partial XML. When data is unavailable, it returns a structured error with a retry hint but without UI messaging. It also reports non-RSS payloads as non-compliant.
Industry/Region & Localization: Adheres to RFCs for XML encoding, RSS specs, and Atom mappings where relevant; uses UTC timestamps and UTF-8 by default. Assumes standard web content distribution contexts.
Assumptions & Exclusions: Assumes access to the feed source or URL; not a content moderation, rendering, or CMS publication tool. Not responsible for live feed hosting or subscriber delivery outcomes.