If the application can send regular e-mails, the answer is almost certainly yes. We can accept messages via standard authenticated SMTP, just as a regular mailserver. This means you usually don't need any custom plugins or development effort to connect your application.

No, you can send messages using our REST API as well. Please refer to the API documentation for more information.

Yes, using Sender Identities. Please let us know if you need assistance in setting this up!

Preferably yes, please add "include:spf.flowmailer.net" (without the quotes) to your SPF records.

Yes, you can use any domain you control, as long as there are no specific deliverability issues such as a conflicting DMARC record.

We disabled some older protocols (SSLv2Hello, SSLv3) and ciphersuites (RC4, ADH en MD5) at our end because of security reasons. Please check your software versions and update to newer ones if possible.