sparkpost - Routing mail through SMTP and also using API -

i have app (saas – laravel/php) built , goal send transactional mails through app , send general emails out through app. transactional mail working via sending domain (configured using spark post’s api-php).

now, want configure system user logging in can send out emails via his/her own email address (which his/her username used log in); i’m thinking message route through sending domain (the ”from header” users email via sending domain).

do set smtp relay in addition job class i’ve created sparkpost’s api ? configure sparkpost’s api; not sure how approach problem. has 1 encountered same issue/found solution?

offering general email sending service broad topic. here basic observations based on question.

full disclosure: work sparkpost.

in summary, use sparkpost or own smtp relay send user mail caveats. imo, using api-driven service simpler manage smtp relay server.

from addresses

first it's important recognise risk of sending mail from customer domains without explicit authorisation domain owners. modern email domains use several mechanisms (spf, dkim, dmarc, ...) ensure authorised parties can send mail on behalf. without these mechanisms, impersonate else on email.

for reason, recommend don't send mail customer email addresses. instead use own domain either generic address usermail@yourdomain.com or user email addresses embedded.

sending general mail

the messages users send through service impact reputation email sender. recommend considering ways provide service while not presenting easy, automatable, sending service spammers. might include limiting types of message, speed or volume people can send, including recaptcha on mailing forms or possibly vetting users before letting them use mailing services.

sparkpost details

the mail send through sparkpost must using sending domain control. since sparkpost manages delivery, mail sent through sparkpost account impact account's reputation unwanted mail cause account suspended. might consider using subaccounts separate each of users' email traffic , understanding how suppression lists protects sparkpost accounts useful.

 smtp relay details

that same caveats in sparkpost details notes apply here you'll have manage relationship each receiving domain (live.com, gmail, etc) directly. app have include usual unsubscribe , bounce handling features.