ENSIP-5: Text Records

Authors: ricmoo.eth

Created: May 17, 2017

Status: final

A standard for storage of text records in ENS (formerly EIP-634).

Abstract

This ENSIP defines a resolver profile for ENS that permits the lookup of arbitrary key-value text data. This allows ENS name holders to associate e-mail addresses, URLs and other informational data with a ENS name.

Motivation

There is often a desire for human-readable metadata to be associated with otherwise machine-driven data; used for debugging, maintenance, reporting and general information.

In this ENSIP we define a simple resolver profile for ENS that permits ENS names to associate arbitrary key-value text.

Specification

Resolver Profile

A new resolver interface is defined, consisting of the following method:

interface IERC634 {
  /// @notice Returns the text data associated with a key for an ENS name
  /// @param node A nodehash for an ENS name
  /// @param key A key to lookup text data for
  /// @return The text data
  function text(bytes32 node, string key) view returns (string text);
}

The EIP-165 interface ID of this interface is 0x59d1d43c.

The text data may be any arbitrary UTF-8 string. If the key is not present, the empty string must be returned.

Global Keys

Global Keys must be made up of lowercase letters, numbers and the hyphen (-).

avatar - a URL to an image used as an avatar or logo
description - A description of the name
display - a canonical display name for the ENS name; this MUST match the ENS name when its case is folded, and clients should ignore this value if it does not (e.g. "ricmoo.eth" could set this to "RicMoo.eth")
email - an e-mail address
keywords - A list of comma-separated keywords, ordered by most significant first; clients that interpresent this field may choose a threshold beyond which to ignore
mail - A physical mailing address
notice - A notice regarding this name
location - A generic location (e.g. "Toronto, Canada")
phone - A phone number as an E.164 string
url - a website URL

Service Keys

Service Keys must be made up of a reverse dot notation for a namespace which the service owns, for example, DNS names (e.g. .com, .io, etc) or ENS name (i.e. .eth). Service Keys must contain at least one dot.

This allows new services to start using their own keys without worrying about colliding with existing services and also means new services do not need to update this document.

The following services are common, which is why recommendations are provided here, but ideally a service would declare its own key.

com.github - a GitHub username
com.peepeth - a Peepeth username
com.linkedin - a LinkedIn username
com.twitter - a Twitter username
io.keybase - a Keybase username
org.telegram - a Telegram username

This technique also allows for a service owner to specify a hierarchy for their keys, such as:

com.example.users
com.example.groups
com.example.groups.public
com.example.groups.private

Legacy Keys

The following keys were specified in earlier versions of this ENSIP.

Their use is not likely very wide, but applications attempting maximal compatibility may wish to query these keys as a fallback if the above replacement keys fail.

vnd.github - a GitHub username (renamed to com.github)
vnd.peepeth - a peepeth username (renamed to com.peepeth)
vnd.twitter - a Twitter username (renamed to com.twitter)

Rationale

Application-specific vs general-purpose record types

Rather than define a large number of specific record types (each for generally human-readable data) such as url and email, we follow an adapted model of DNS's TXT records, which allow for a general keys and values, allowing future extension without adjusting the resolver, while allowing applications to use custom keys for their own purposes.