Signing up without an email

Lium can create an account in one click — no email, no password, no wallet. Instead of a password you get a fingerprint: one 32-character string that is both your login and the only way back into the account. Despite the name, this is not a passkey, WebAuthn or biometrics — it is a random 32-character string you store like a password, and a script or an agent can obtain one through the HTTPS API (see Script it).

Use it when:

• You want to rent a GPU right now and don't want to hand over an email address.
• An AI agent or a script is signing up on your behalf, headless, with no mailbox to confirm.
• You're trying Lium out and will decide about a real account later.

If you want password resets, receipts and balance alerts in your inbox, sign up with an email instead — see Quickstart.

What a fingerprint is

A fingerprint is a 32-character random string, for example:

9lbcaReNipAqVExn7VJXpHMm5IFNZRae

It carries 192 bits of randomness, so it can't be guessed. Lium stores only a hash of it, the same way passwords are stored. That has one consequence worth repeating:

The fingerprint is shown exactly once

Nobody at Lium can look it up, resend it or reset it — not support, not the founders. Lose the fingerprint and the account is gone, along with any balance on it.

A fingerprint is not an API key. The fingerprint signs you in to the dashboard; an API key authenticates requests to the API. Signup always mints the fingerprint and tries to mint an API key; if that best-effort step fails, you can create a key later on the Access page.

Sign up

1. Go to lium.io/register.
2. Press Register with fingerprint. There is nothing to fill in — Lium names the account for you (lium_a1b2c3).
3. Save the fingerprint from the screen that follows — copy it into your password manager, or use Download as .txt. Then tick the confirmation box and continue.

New accounts may get $5 in free credits when the platform has free credit enabled and no other account has claimed it from the signup IP. The account is still created when either check fails — just without the bonus.

Script it

The web form is optional. The same signup is a single unauthenticated POST, which is what makes this flow work for an AI agent or a script with no mailbox to confirm:

# an empty body is the whole request — the server names the account
curl -fsS -X POST https://lium.io/api/auth/signup \
  -H "Content-Type: application/json" \
  -d '{}'

{
  "user_id": "ec8c2436-1039-45aa-a508-bcbe865fbcd8",
  "username": "lium_a1b2c3",
  "fingerprint": "9lbcaReNipAqVExn7VJXpHMm5IFNZRae",
  "api_key": "sk_...",
  "signup_credit_granted": true
}

Save fingerprint first — the response is the only place it ever appears, and it is the only way back into the account. When api_key is a string, it is ready to use without a verification step; renting then requires a balance sufficient to cover the minimum rental window:

curl https://lium.io/api/pods -H "X-API-Key: sk_..."

api_key can come back null: minting it is best-effort, and a failure there never blocks the signup. In that case sign in with the fingerprint and create a key yourself — see API keys. signup_credit_granted tells you whether the free credit landed; read it instead of assuming, since it is false both when the grant is switched off and when the credit was already claimed from your IP.

username is only a display name — the fingerprint alone signs you in, and the web form does not ask for a name at all. Omit it and the server generates lium_ plus six hex characters. Send one and it must be 3–32 characters from a-z A-Z 0-9 _ -, with 409 if it is already taken. The endpoint is rate-limited per IP, with the same numbers as the form — see Sign in below. Signing up through the API is the only headless way into this flow today: the Lium CLI creates email accounts, not fingerprint ones.

Sign in

1. Go to lium.io/login.
2. Scroll to or sign in with your fingerprint.
3. Paste the fingerprint and press LOGIN WITH FINGERPRINT.

Wrong fingerprints all get the same answer — Invalid fingerprint — whether the account exists or not. Per IP address, sign-in is limited to 10 attempts per minute and signup to 5 per minute and 20 per day; past that, wait and try again.

What you give up without an email

	Email account	Fingerprint account
Sign in with	Email + password	Fingerprint
Forgot the credential	Reset by email	Account is lost
Email notifications (receipts, low balance)	Yes	Not delivered
Rent pods, use the API and CLI	Yes	Yes
$5 signup credit	Conditional on platform and signup IP	Conditional on platform and signup IP

Everything about renting works the same: pods, volumes, backups, templates, the CLI and the API behave identically for both kinds of account.

Storing it safely

• Put it in a password manager as you would a password.
• Treat it like a bearer token: anyone who has the string is you, and can spend your balance.
• Don't paste it into a pod, a screenshot, a support ticket or a public repository. Lium support will never ask for it — see Official support and scams.
• Keep a second copy somewhere offline. There is no recovery path.