Welcome to the Open Profile Data Exchange (OPDX) protocol specification!

What is OPDX?

OPDX (Open Profile Data Exchange) is a decentralized protocol for retrieving public profile data (such as avatars) associated with an email address. The protocol allows email providers and self-hosted instances to expose profile data in a standardized way, without relying on a centralized service, like Gravatar.

Features

  • 🔓 Open & decentralized
  • 🤫 Privacy-focused
  • 🌎 Compatible with multiple providers

Design Principles

  1. Open & Decentralized – Anyone can build and host an OPDX-compatible instance. Which server, framework or language to use is completly in the hands of developers, as long as the instance complies with the OPDX specification.
  2. Privacy-Conscious – No authentication required. Rate-limiting and caching are optional, but should be considered.
  3. DNS-Based Discovery – Clients discover OPDX servers using a simple TXT record. There is no need for a central instance or directory of instances.
  4. Minimal & Lightweight – The protocol mandates simple REST API requests and responses using a standardized JSON format.