Person ↔ person

Hand off something of value

You're giving a $50 voucher to a friend — or a stranger who won your giveaway. Today that means hoping the email address you typed belongs to the right person. With handles on both sides, the transfer targets username.md/them: the issuer's system looks up the recipient's handle, checks the signature on the response, and delivers to the verified endpoint it finds there. The voucher goes to the person who controls that handle — not to a typo, and not to a lookalike who registered a similar-sounding email an hour ago.

# before releasing the voucher: resolve the recipient and verify the signature $ curl -sI -H 'accept: application/json' https://username.md/v1/users/dana/profile \ | grep -iE 'content-digest|signature' # signature verifies against the platform's published key → deliver # signature fails → stop. No voucher for impostors.

The same pattern covers gift cards, tickets, credits, referral rewards — anything where "did this reach the right human?" is the whole problem.

Person → market

Sell something to a stranger

Selling a guitar, a couch, a domain? The buyer's real question is never about the item — it's "is this seller real?" A handle answers with facts instead of vibes: verified claims (a domain proven by DNS, a bound Bluesky account, imported Keybase proofs) that anyone — including the buyer's AI agent — can check before money moves. Your reputation stops being trapped inside one marketplace's star rating and becomes something you carry with you, listing to listing, platform to platform.

# buyer (or buyer's agent) checks the seller's verified claims first $ curl -s https://username.md/v1/users/chris/claims # → { "claims": [ { "type": "dns", "domain": "chrisbergeron.com", "jws": "..." }, ... ] }

Drop your handle in the listing. Serious buyers verify it in one request; scammers can't fake the signature.

Agents → you

Agents come to you — not the other way around

The old web made you go to every service and fill out the same forms, over and over, keeping dozens of profiles in sync by hand. The agentic web inverts that: software acting for other people fetches your handle — as JSON, Markdown, or a signed response — and gets your links, your keys, and your rules for how you want to be contacted. You publish once, on a name you control, and every agent that needs to know something about you comes and asks. Change a link once; every future lookup gets the new answer.

# an agent reads you in the format it prefers $ curl -s -H 'accept: text/markdown' https://username.md/v1/users/chris/profile # and reads your standing instructions for agents $ curl -s https://username.md/users/chris/llms.txt
Institution → you

Your records, delivered to you

Think about how your medical records move today: from your provider to a third-party records vendor, through a portal you log into with yet another password, on terms set by everyone except you. A verified handle changes the destination. Because your handle publishes a signed, verifiable endpoint that provably belongs to you, an institution can release your records directly to you — encrypted to your published key, delivered to the endpoint you designated — with cryptographic proof that the recipient was really you. The middleman stops being a requirement and becomes a choice.

# the institution resolves your handle to a public key + delivery endpoint $ curl -s https://username.md/users/chris/.well-known/did.json # → public keys + service endpoints, signed — encrypt to the key, deliver to the endpoint

username.md is not a medical-records product and doesn't store health data. This is what the open primitives — did:web, published keys, signed endpoints — make possible for any institution that sends people their own documents: clinics, schools, banks, insurers, courts.

Security

Why any of this is trustworthy

Every use case above rests on the same foundation — and it's live today.

Every answer your handle gives is cryptographically signed (RFC 9421 HTTP Message Signatures, Ed25519) and verifiable against public keys anyone can fetch. Claims on your profile aren't self-asserted text — they're checks that were actually performed (DNS records, account bindings, re-verified Keybase proofs) and sealed into signed statements that verify even offline. Private keys are generated per handle and stored encrypted server-side; verification needs only public information. There is no "trust us" step: a relying party that can run curl can audit the whole chain. The full verification walkthrough, in four languages, is in the developer guide.

Privacy & personal safety

Being findable shouldn't mean being followable

A handle makes you easy to verify. It should never make you easy to stalk. Here's our model — including the honest status of each control.

What protects you today

Your handle publishes only what you put on it. No home address, no phone number, no legal name is required — a handle with a single link, or nothing at all, is a valid handle. Signed responses cut the other way too: nobody can impersonate you, stand up a convincing fake profile under your name, and pass verification — the signature math fails. And this site runs cookie-free, privacy-friendly analytics; we don't build behavioral profiles of visitors or of you.

Safety controls we are building

For people dealing with a stalker, a harasser, or an abusive ex, "just delete your profile" is not a safety plan — disappearing entirely often isn't an option. These controls are designed for that reality:

  • IN DEVELOPMENT Per-person null-routing. Block a specific person or agent, and their lookups of your handle return the same result as a handle that doesn't exist — byte-for-byte identical to a real 404. No "you've been blocked" tell, no confirmation that you're even on the platform. To them, you simply aren't here.
  • IN DEVELOPMENT Allowlist mode. Flip your handle to approved-parties-only: nobody resolves your profile unless you've let them in. The strictest setting — your handle keeps working for the people and agents you choose, and no one else.
  • IN DEVELOPMENT Blocklist mode. The default-open inverse: your handle stays public, and the specific parties you name are null-routed as above.
  • IN DEVELOPMENT Lookup visibility. An audit trail of authenticated lookups against your handle, so unusual attention is something you can see — and act on — early.
# design target: these two responses are indistinguishable $ curl -s -o /dev/null -w '%{http_code}\n' https://username.md/v1/users/no-such-handle/profile 404 $ curl -s -o /dev/null -w '%{http_code}\n' https://username.md/v1/users/handle-that-blocked-you/profile 404

If you're in danger now and need content removed immediately, contact support — a human handles takedown-for-safety requests ahead of everything else in the queue.

Badge & verifier

Ways people use the badge and verifier

The verifier is live for anyone who can make an HTTP request. The badge — your personal mark as a sign-in button and embeddable proof — is in development.

Prove a listing is yours

Put your handle on a marketplace listing, storefront, or auction. Buyers verify the signed profile in one request and know the seller behind the listing is the person behind the handle.

Verify before you pay

Invoice from a new contractor? Resolve their handle, check the signed claims, then pay. Impersonation-based invoice fraud dies when "check the signature" is one command.

Meet someone from the internet

Before a meetup, a date, or a sale in a parking lot: they send their handle, you verify it resolves and the claims check out. The person you meet is the person you vetted.

Sign in with your own badge

Your hand-drawn mark becomes your sign-in button. A phishing page can copy a logo — it can't draw your mark. In development as the Signature SSO Badge.

Embed proof in your signature

Drop your handle in your email footer, bio, or resume. Any recipient — human or agent — can verify it's really you, without asking you to prove anything twice.

Gate your own doors

Running a community, a beta, an allowlist? Accept handles instead of emails and let the verifier do the vetting: real, signed identities in; throwaways out.

Radical honesty

What's live today vs. what's coming

No fine print, no vapor. This table is the truth as of today.

CapabilityStatus
Signed profile lookups + verified claims (the verifier every use case builds on)LIVE
did:web documents with published keys + service endpointsLIVE
Agent-readable formats (JSON, Markdown, per-handle llms.txt)LIVE
Signature SSO Badge (sign in with your own mark)IN DEVELOPMENT
Per-person null-routing (blocked lookups identical to 404)IN DEVELOPMENT
Allowlist / blocklist resolution modesIN DEVELOPMENT
Lookup visibility / audit trailIN DEVELOPMENT

Kept in sync with llms.txt, the same status file we serve to AI agents. The full capability table lives on How it works.

Own the name that answers for you

Founding access: $9 reserves your handle today. The profile API, signed responses, and Bluesky binding are live now; full refund if we don't ship the rest by 2026-09-30.