Senders and SMTP credentials

Sending has two halves, and they answer different questions.

A sender is an identity — a name and address your organization is allowed to send as, like Ada from Example <ada@example.com>. An SMTP credential is a login your own software uses to hand messages to Mailyte: your website's contact form, your invoicing system, whatever sends mail without a person clicking Send.

Both live under Sending, as two tabs of one page, because you usually need to think about them together.

A sender answers who the message is from. Verifying one is how Mailyte knows the address belongs to you and not to somebody typing it into a form.

An SMTP credential answers what is allowed to connect. It is a username and password scoped to one domain, and it is not the same thing as a mailbox password or an API key — a point worth remembering when something stops working, because the three are revoked and rotated separately.

When you create a credential, Mailyte shows you the password once. It is stored only as a hash, which means nobody — including Mailyte's own staff — can read it back to you afterwards. If it is lost, you create a new one and delete the old.

Alongside the password you are given the host and port to connect to. Those two, plus the username and password, are the four things every mail library on earth asks for.

To add a sender

1. Go to Sending, on the Senders tab.
2. Add the name and address you want mail to come from. The domain must already be verified — see Setting up your domain.
3. Confirm it, and the identity becomes available to send as.

To create an SMTP credential

1. Go to Sending and open the SMTP Credentials tab.
2. Create a credential and choose the domain it may send for. Give it a name that says which system uses it — website-contact-form beats smtp1 when you are looking at a list of six a year from now.
3. Copy the password immediately. It is shown once and never again.
4. Copy the host and port shown next to it.
5. Put all four values into your application's mail settings: host, port, username, password. Use one credential per application, so you can revoke one without breaking the others.
6. Send a test message from that application and confirm it arrives.

Your application says authentication failed. Check you are using the SMTP credential's username and password, not a mailbox password and not an API key. If the credential was deleted, create a new one — the old password cannot be recovered.

You lost the password. It cannot be shown again. Create a replacement credential, update the application, then delete the old one.

Mail sends but arrives in spam. That is a domain-authentication question, not a credential one. Check that SPF, DKIM and DMARC are all found under Domains.

Mail is refused with a message about the sender. The address your application puts in the From field must be one you are allowed to send as, on a domain the credential covers. A mismatch between the two is the usual cause.

Nothing sends at all, from anything. Check the domain is still Active under Domains before looking at your code.

• Setting up your domain — required before either half works
• Creating mailboxes — addresses for people rather than systems
• Go to Sending