SendGrid with Laravel: SMTP mailer env config

TL;DR: Configure Laravel's SMTP mailer for SendGrid via MAIL* env vars: host, the literal apikey username, TLS on 587, and a verified MAILFROMADDRESS. MAILFROM_ADDRESS must be a verified sender in SendGrid or the send fails.

The fix

1. MAIL_USERNAME is the literal string apikey. Putting your email here is the classic failure.
2. MAIL_ENCRYPTION=tls pairs with port 587. Port 465 wants ssl.
3. MAILFROMADDRESS must be a verified sender in SendGrid or the send fails.
4. After changing .env, clear the config cache (config:clear) or the old values stick.
5. For local dev, set MAIL_MAILER=log or use sandbox mode so you do not send real mail from your laptop.

When to use this

• This covers exactly what the title says: SendGrid with Laravel.
• You are setting this up for the first time, or auditing an existing setup.
• You want the key gotchas in one place before you start.

When not to use this

• You are doing a different workflow with SendGrid; these steps are specific to the title above.
• You need the full reference docs; this is the short path, not the manual.

Compatibility

• Not pinned to a specific version; follows current SendGrid behavior.

Laravel's SMTP mailer plus the official SendGrid SMTP settings. The framework reads MAIL_* env vars; the SendGrid-specific facts are the host, the literal apikey username, and port 587 with TLS. Sources: https://github.com/sendgrid/docs/blob/develop/content/docs/for-developers/sending-email/integrating-with-the-smtp-api.md