Contact Directory - Desired Properties


Propose key properties of the contact directory.

What is a contact and what is it used for?

See here for more information.

What is the contact directory?

A place to maintain XMTP user contact information.

Value of the contact directory for the ecosystem

  • Facilitates user ownership of XMTP contact identifier
  • Represents the social graph of the messaging network

Key Properties

  • Immutable
  • Shelling point
    • Perceived strength of trustless ownership guarantees
  • Interoperable
  • Censorship resistant
  • Sybil resistant
  • Affordable for users or providers to maintain contact information


  • Does privacy matter for a user’s contact profile?
    • Is there sensitive metadata, such as blocklist that will be stored in the contact directory?
    • Are there existing solutions that maintain user privacy, yet enable public access to the state?
  • What does interoperability mean here?
  • Should users and providers have the option to pay for a contact identifier that is trustlessly owned onchain vs having a free version that is held by a trusted custodian offchain?
  • How will installation keys be revoked? Does it make sense to have automated expiration?
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