Skip to main content

FAQ

Product​

Does Signitize check that the mailbox exists?​

No. deliverable: true means the domain accepts mail and the username follows the provider's rules. Probing mail servers about individual mailboxes is unreliable and gets servers blocked, so keep sending a verification email. See what deliverable: true does not mean.

Should I reject addresses with a +tag?​

No. +tags are a standard feature of Gmail, Outlook, iCloud and others, and real people use them. Store the canonical email in a unique column and aliases are caught as duplicates. See Subaddressing.

Are privacy relays like @duck.com or Firefox Relay blocked?​

No. They return disposable: false because they forward to a real, long-lived inbox, and each relay address counts as its own inbox. If your product must reject them, keep your own list of relay domains.

Which address should I send my verification email to?​

The one the user typed. The canonical email is a duplicate-check key and may not be a mailbox. See Two addresses, two jobs.

What happens if Signitize is down?​

Your signup must still succeed: create the account as pending and recheck it later. See Never block a signup.

Do you store the addresses I check?​

No. We store how many checks your account made each month, not the addresses. The only thing we keep from checks is the list of throwaway domains we detect (and their mail servers), so the next address at those domains is caught faster. See the Privacy Policy.

Can I call the API from the browser?​

No. Your API key would be visible to everyone. Call Signitize from your backend.

Plans and billing​

Is Premium a subscription?​

No. It is a one-time payment for 30 or 365 days that never renews automatically. See Plans & billing.

What happens when my quota runs out?​

/v1/check answers 429 with QuotaExceededError until the 1st of next month, 00:00 UTC. Upgrade to Premium to raise the limit right away. See Monthly quota.

Do I need a new key when I upgrade?​

No. Pay with the email address of your account and your existing key gets the Premium limits immediately.

Keys​

I lost my API key. Can you send it to me?​

We can't: we never store keys. Use Lost your key? in the Get API key window to get a link for a new key. Revealing it revokes the old one. See API keys.

Can I have several keys?​

No. Each account has one active key. Aliases of one inbox ([email protected], [email protected]) belong to the same account. If you need separate keys for separate products, tell us.

Support​

How do I contact support?​

Email [email protected]. For anything about your account, write from the email address you registered with. See Support & feedback.