Today, I'm announcing https://username.md !
username.md is a single identity URL: username.md/<your name> - that content-negotiates on the `Accept` header. It serves an HTML profile page; an agent or curl gets Markdown, JSON, JSON-LD, or a JWT. The same URL serves different representations based on request header. So the page a human reads and the data a machine parses never drift apart.
The interesting part is that every response can be signed and verified. Each handle gets an ED25519 keypair (private key AES-GCM-wrapped at rest), publishes a did:web document, and serves RFC 9421 signed responses. Claims about you — GitHub, a domain you control, an ATProto handle — are W3C Verifiable Credentials, verified before they're shown (e.g. domain ownership via a DNS-TXT challenge). So "this is really them" can be confirmed by a machine instead of taken on faith.
It can also bridge the identities you might already use, like ATProto because it supports did:web. Every username.md handle is a valid Bluesky identity root, and you can even import from Keybase.
Why we built it: usernames on every platform are rented. The platform owns the namespace, the verification badge, and the audience. As agents start conducting business on our behalf, "who is this, and can I prove it" becomes an accountability and governance issue. I wanted an identity surface that's mine, portable, and cryptographically verifiable; which anyone can have if they own a domain (mine is https://chrisbergeron.com, feel free to review the metadata). But I wanted to bring DID:web functionality to the mass market. You can get a username for yourself, for an agent, or multiple agents.
Free tier gets you a public, signed profile at your handle. Pro ($49/yr; coming soon!) adds you@username.md email forwarding with per-service aliases, custom CSS, and an MCP endpoint so an agent can query your profile as tools.
The stack is a Python identity kernel, per-user keys, CloudFlare in front of the origin. Infra is hosted at AWS, built multi-region for HA but only one region is live right now. I'm a platform and security guy, so the frontend and marketing copy was augmented with AI.
I'm sure you'll find bugs and typos but hopefully few inconsistencies. It's an MVP and I would never be able to ship if I kept engineering, tweaking and optimizing. So, here it is for you to enjoy, explore, and build upon - today.
I have some really exciting things on the roadmap so I hope you join me and start building on top of username. The capabilities are super exciting and we're just getting started.
This may be the beginning of a new category: SSO as a Service.