W3C Feed Validation Service

Check the syntax of Atom or RSS feeds

Tutorials

• How do I declare namespaces in my RSS feed?
• How do I install and run the Feed Validator?

Specifications

• Atom 1.0
• RSS 1.0 specification
• RSS 2.0 specification

Validator messages

Errors

• foo should not have text (all data is in attributes)
• Feeds must specify XML Version 1.0
• Categories can't have both href and foo attributes
• Categories can't have both href attributes and children
• Feeds must not contain SYSTEM entities
• Current not self in complete feed
• The use of this DTD has been deprecated by Netscape
• Duplicate alternate links with the same type and hreflang
• foo contains more than one bar
• All entries have the same id
• element values must not be duplicated within a feed
• skipDays can not contain more than 7 day elements
• foo link relation found in complete feed
• HTTP Error
• HTTP error with content that looks like a feed
• HTTP Protocol Error
• IO Error
• Incorrect day of week: foo
• attribute value too large
• Invalid value for access:restriction: foo
• foo must be an email address
• foo must be alphanumeric
• Invalid altitudeMode
• foo must be between -360 and 360
• foo attribute of bar must be 'true' or 'false'
• Not a valid color
• Invalid colorMode.
• foo must be comma-separated integers
• Invalid email address
• foo is not a valid mode
• Invalid Coordinate
• Invalid Coordinate
• Invalid counry code: "foo"
• Invalid Credit Role
• Invalid value for g:currency: "foo"
• foo must be Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday
• This feed contains conflicting DOCTYPE and version information
• Invalid duration: "foo"
• Invalid character encoding: foo
• <expansionState> is a comma-separated list of line numbers.
• Invalid value for foo: "bar"
• Invalid value for foo: "bar"
• Invalid form component name
• element must be a full URI
• Invalid value for g:location: "foo"
• Invalid value for g:gender: "foo"
• foo must be between 1 and 400
• foo must be between an integer 0 and 23
• guid must be a full URL, unless isPermaLink attribute is false
• foo must be a valid IRI
• foo must be an ISO-8601 date
• foo must be an ISO-8601 date-time
• Invalid value for foo: "bar"
• foo must be an integer
• foo attribute of bar must be a positive integer
• Invalid state for Icon
• foo is not one of the predefined iTunes categories or sub-categories
• foo is not one of the predefined iTunes episode type
• foo is not one of the predefined iTunes channel type
• Invalid coordinate list. Make sure that coordinates are of the form longitude,latitude or longitude,latitude,altitude and seperated by a single space. It is also a good idea to avoid line breaks or other extraneous white space
• Invalid latitude found within coordinates. Latitudes have to be between -90 and 90.
• Invalid longitude found within coordinates. Longitudes have to be between -180 and 180.
• Invalid units.
• Invalid value for g:label: "foo"
• foo must be an ISO-639 language code
• foo must be between -90 and 90
• foo must be a valid URI
• Invalid list item type
• Invalid local parameter name: foo
• Invalid local role: foo
• Invalid value for foo: "bar"
• foo must be between -180 and 180
• foo attribute of bar must be a valid MIME type
• foo is not a valid MIME type
• Invalid value for g:marital_status: "foo"
• Invalid content expression: "foo"
• Invalid Media Hash
• Invalid content medium: "foo"
• Invalid Media Rating
• media:restriction must be 'all' or 'none'
• relationship must be 'allow' or 'deny'
• type must be 'country' or 'uri'
• type attribute must be "plain" or "html"
• Invalid value for content: "foo"
• Invalid value for name: "foo"
• foo must be an NPT-time
• Invalid Namespace Specific String: attribute
• foo is in an invalid namespace
• foo must be a non-negative integer
• The "version" attribute for the opml element must be 1.0, 1.1 or 2.0.
• Invalid value for g:payment_accepted: "foo"
• foo must be a percentage
• guid must be a full URL, unless isPermaLink attribute is false
• foo must be a positive integer
• Invalid value for g:price_type: "foo"
• RDF Parsing Error
• element must be an RFC-822 date-time
• foo must be an RFC 3339 date-time
• Invalid RSS Version: x.y
• Invalid value for g:rating: "foo"
• Invalid refreshMode
• Invalid value for g:reviewer_type: "foo"
• Invalid value for g:salary_type: "foo"
• Invalid Schema field type
• Invalid value for g:service: "foo"
• Invalid value for sx:related type
• Invalid key for StyleMap.
• Invalid value for SyndicationRight: foo
• foo is not a valid TAG
• type attribute must be "text", "html", or "xhtml"
• foo attribute of bar must be 'true' or 'false'
• foo is not a valid URI
• foo attribute of bar must be a valid URI
• foo attribute of bar must be a full URL
• foo is not a valid URN
• foo is not a valid UUID
• foo must be hourly, daily, weekly, monthly, or yearly
• Invalid character in a URI: c
• Invalid value for foo: "bar"
• Invalid viewRefreshMode.
• foo must be an W3CDTF date
• foo must be between 1 and 144
• Invalid value for g:year: "foo"
• foo attribute of bar must be 'yes' or 'no'
• foo attribute of bar must be 'yes', 'no', or 'clean'
• Invalid value. Should be 0 or 1.
• item must contain either title or description
• Link past end of list
• media:group must have multiple media:content children
• Missing trailing slash in mediaRSS namespace
• foo must appear before all entries
• Missing element attribute: attribute-name
• Missing by and when attributes
• Missing content or alternate link
• Missing foo element: description
• Missing parent element: child
• foo must have an href attribute
• Missing foo element: link
• Missing namespace for foo
• Missing Summary
• Missing foo element: title
• Missing xhtml:div
• There is no blink element in RSS
• thr:when attribute obsolete; use thr:updated instead
• foo claims to be base64-encoded, but isn't
• skipHours can not contain more than 24 hour elements
• foo claims to be escaped, but isn't
• Missing namespace for foo
• searchTerms must be URL encoded
• Feed uses an obsolete namespace
• XML Parsing error: syntax error
• Since After until
• length of nnn exceeds the maximum allowable for foo of mmm
• foo contains more than ten bar elements
• Undeclared foo prefix: bar
• Undefined parent element: child
• Undefined named entity: foo
• Unexpected foo attribute on bar element
• Unexpected text
• Whitespace not permitted here
• UnicodeError: decoding error, invalid data
• Unknown XML character encoding: foo
• IRI found where URL expected
• Use zero for unknown length
• Unable to validate, due to hardcoded resource limits (limit)
• Blank line before XML declaration (WordPress)

Warnings

• Archive incomplete
• foo should not have text (all data is in attributes)
• foo attribute of bar should not be blank
• Avoid Namespace Prefix: foo
• Avoid Text Input
• The XML encoding does not appear to match the characters used.
• Encode "&" and "<" in plain text using hexadecimal character references.
• wfw:commentRSS should be wfw:commentRss
• name should not contain email address
• element should not contain HTML
• element should not contain relative URL references
• foo should not contain HTML unless declared in the type attribute
• Comma found in coordinate pair
• style attribute contains potentially dangerous content
• foo has been superceded by foo.
• media:adult is deprecated
• root:// URLs have been superceded by full http:// URLs
• Avoid foo:bar
• item contains more than one enclosure
• Two entries with the same id
• An item should not include both foo and bar
• A channel should not include both foo and bar
• Two entries with the same value for atom:updated
• Email address is not in the recommended format
• Your feed appears to be encoded as "this", but your server is reporting "that"
• foo link relation found in entry
• type foo/bar used for a document fragment
• Image link doesn't match channel link
• Image title doesn't match channel title
• Image not in required format
• Implausible date: foo
• Non-boolean value for AdultContent: foo
• Use commas to separate keywords
• foo is an invalid KML media type. Use application/vnd.google-earth.kml+xml or application/vnd.google-earth.kmz
• The type attribute on an <outline> element should be a known type.
• An <outline> element whose type is "rss" may have a version attribute, whose value must be RSS, RSS1, RSS2, or scriptingNews.
• Misplaced Item
• Misplaced XHTML content
• Missing atom:link with rel="self"
• current link not found in archive feed
• No character encoding was specified
• item should contain a guid element
• Placemark should contain a id attribute
• Missing recommended iTunes parent element: child
• The recommended <itunes:email> element is missing
• An <outline> element with more than just a "text" attribute should have a "type" attribute indicating how the other attributes are to be interpreted.
• Email address is missing real name
• Missing recommended element attribute: name
• Missing atom:link with rel="self"
• Missing source element: foo
• Missing Textual Content
• Missing outline attribute: title
• Missing content attribute: type
• Missing outline attribute: url
• An <outline> element whose type is "rss" must have an "xmlUrl" attribute.
• Ensure description precedes content:encoded
• Identifier "foo" is not in canonical form (the canonical form would be "bar")
• 'type/subtype' media type is not specific enough
• element should not be blank
• Invalid HTML: explanation
• foo claims to be inline, but may contain HTML.
• The specified guid is not sufficiently unique.
• iTunes elements should only be present in feeds encoded as UTF-8
• Obscure XML character encoding: foo
• foo is an obsolete iTunes category or sub-category
• Feed is an obsolete version
• Obsolete Wiki Namespace
• Problematical RFC 822 date-time value
• Undocumented use of element
• Relative href value on self link
• The prefix name generally is associated with the namespace http://some/other/namespace
• Same-document reference
• URI scheme not IANA registered: foo
• element should not contain script tag
• element should not contain script attribute
• Self reference doesn't match document location
• "self" link references a non-Atom representation.
• OpenSearchDescription should include an example Query
• Ensure lastBuildDate is present when slash:comments is used
• Undefined media-range parameter
• Missing namespace for foo
• Feeds should not be served with the 'type/subtype' media type
• Unknown host: name
• Use of unknown namespace: http://namespace.uri/
• Unregistered link relationship: foo
• Format foo is not supported by iTunes
• Unable to validate namespace: http://namespace.uri/. See the foo specification at http://namespace.uri/specification
• Use of extension attribute on RSS 2.0 core element: (namespace,name)
• Use zero for midnight

Information

• This encoding is not mandated by the XML specification: foo
• Date should be a UTC date

This service uses the Feed validator software. Please report any issues on GitHub.