In the wild several twtxt users came up with metadata comments in their twtxt files for different purposes. So the Metadata extension is actually not invented at twtxt.net. However, this specification tries to settle on a common standard as extension to the original Twtxt File Format Specification.
Twtxt feed authors might want to provide additional information for their feeds or about themselves which clients can pick up and display in a suitable way.
Whenever a physical line in a twtxt file starts with a hash sign (
#) it is
considered a comment. The comment ends at the end of the line. Comments are
usually ignored by twtxt clients and can appear anywhere in a feed. Comments
must not be preceded with whitespace.
# this is a comment ### # this one, too
All metadata are part of comments, so they can be easily ignored by clients which do not support metdata.
Metadata are simple key value pairs, they consist of a field name and a field
value. Field names and values are separated by an equal sign (
=). Each field
is on its own physical line. Field names are case insensitive and can contain
any number of ASCII letters, digits, minuses and underscores. Whitespace is not
allowed as part of the field name. Field names must consist of at least one
Field values start after the first equal sign (
=) if that follows a valid
field name. They are case sensitive and can contain anything, there is no
character restriction other than line breaks. Values end at the end of the
line. Multiline values must use the Unicode line separator
U+2028 just like
multiline twts do.
All whitespace around field names and values must be stripped. Both field names
and values must not be empty. There must be no more than one hash sign (
preceding fields. If fields cannot be parsed, they must be ignored and treated
as regular comments.
# field-name = field value
It is legal for the same field name to appear more than once. The format allows
this, but it doesn’t make sense for all fields. For example, it is reasonable
to have many
follow fields (one for each feed that a user is following), but
you probably won’t find multiple
description fields. The order of fields with
the same name must be kept so clients can work with them properly.
Valid meta data examples are:
# url = https://example.com/twtxt.txt #nick=joe #description =This feed tells about my everyday adventures.
This section describes common fields and their purposes.
This specifies the URL(s) of the feed. There might be several
url fields in a
single feed. Feeds may be served over multiple protocols, e.g. HTTPS, HTTP and
url fields advertise the available choices. The first
field value will be used for twt hashing.
Clients must not automatically change the URL to actually fetch the feed based
on this field. However, they might ask the user for confirmation to update the
feed URL if they detect that the fetch URL does not match any of the provided
url field values.
Automatically updating the feed URL could result in feed spoofing without the user noticing.
This is the feed author’s nick name. When following feeds clients can suggest to go with this nick.
For security reasons clients should not automatically update local nicks without user consent. Otherwise users can be tricked into believing twts are coming from somebody else they’re following. Clients should ask the users when a nick change is detected.
This specifies the URL for the author’s or feed’s avatar, so it can be displayed along twts, e.g. next to the author. The avatar image is typically in JPEG, PNG or WebP format. Different clients prefer different ratios, so there is no strict rule to follow for feed authors. Often avatars are square.
avatar field is missing, it is up to the client how to visually
represent the author’s feed. Some clients such as
yarnd will automatically generate an
avatar based on available data like the feed’s preferred nickname and its URL.
description field contains an explanation what the feed is about. Clients
might display this information in a feed details view.
Publicly discloses that the feed author is following another twtxt feed. This can be helpful to aid feed discoverability. The value contains the nick and the URL of the feed separated by whitespace:
# follow = joe https://example.com/twtxt.txt
The number of feeds the author is following.
# following = 42
The number of followers this feed has.
# followers = 23
A link to some other resource which is often connected to the feed or author.
follow fields the syntax for
link values consists of a link text
followed by whitespace and the actual URL. However, the link text can contain
# link = Blog https://example.com/blog/ # link = All my source code https://git.example.com/
This field is used by the Archive Feeds Extension.
This optional field is used by feed authors as a hint to clients to control how often they should fetch or update this feed.
The value of this field is seconds represented by an integer.
NOTE: An empty, bad, or unparsable value is ignored.
- 2021-10-09: Initial version.
- 2021-10-31: Clarify that metadata field values must not be empty.
- 2021-12-26: Clarify that clients must not automatically change the feed URL to fetch the feed based on
urlmetadata field values.
- 2021-12-29: Add new
refreshmetadata field to hint to clients how often a feed can or should be fetched.