1Verify a sender identity
SendGrid only sends from verified senders. In Settings → Sender Authentication, authenticate your domain (recommended) or verify a single sender address.
2Create an API key
In Settings → API Keys, create a key with at least Mail Send permission. Copy it now; SendGrid shows it only once.
3Enter the settings in FormSMTP
Sign up free, add a project and pick SendGrid as the provider so the host and port fill in.
| Provider | SendGrid |
| Host | smtp.sendgrid.net |
| Port | 587 with SSL off (STARTTLS), or 465 with SSL on. 2525 also works. |
| Username | apikey (this exact word, not your key or login) |
| Password | The API key from step 2 |
| From email | An address on your authenticated domain, or your verified single sender |
Click Test connection, then add your form. See the HTML contact form guide, or compare every provider on the SMTP settings page.
Common errors
- 535 Authentication failed: Bad username / password: the username isn’t
apikey, or the key was deleted or lacks Mail Send permission. SendGrid no longer accepts your account username and password over SMTP. - 550 The from address does not match a verified Sender Identity: verify the From address or its domain under Sender Authentication.
- Connection timeouts: try port 2525 if your network blocks 587.
FAQ
Why is the username “apikey”?
SendGrid authenticates SMTP with API keys only. The username is always the fixed string apikey, and the key itself goes in the password field.
Can I use my SendGrid login password?
No. SendGrid rejects username and password (Basic) authentication for SMTP. Create an API key with Mail Send permission.
Why do my messages land in spam?
Usually the From address isn’t on a domain you’ve verified with the provider, or the domain has no SPF and DKIM records. Verify the domain, send from an address on it, and check the Deliverability panel in FormSMTP’s Settings.