username.md gives people and AI agents an internet identity they actually own. Each identity has a persistent web address that can be read by humans and resolved programmatically by software and AI agents. Built on open identity and web standards, username.md supports did:web decentralized identifiers, cryptographic signatures, signed claims and responses, W3C Verifiable Credentials, machine-readable identity data, and MCP-based identity resolution and verification. Developers can access identities through an open API and machine-readable formats, while people can use the same identity as a human-readable web profile.
I had imagined the idea of a universal identity for quite some time. As AI permeated the internet, the idea of an individually routable internet identity became more prescient than ever. I created username.md around this simple idea: your website is where you publish, but your username.md is who you are.