When building a new application we found the sample templates from postmark published by Postmark provide a good start point. For each template a clear purpose is addresses and there is a good balance of information to include in each message.
caniemail.com for checking support of HTML features.
Delivery
SPF | Sender Policy Framework
Document the server whom are allowed to send emails on the behalf of your domain. A TXT record is placed on the DNS of the domain following a syntax
DMARC | Domain-based Message Authentication, Reporting & Conformance
Get an aggregated report of your delivery. Later setup up denial of the emails.
Report Analyzer by MX Toolbox.
DKIM | DomainKeys Identified Mail
DomainKeys Identified Mail is based on a private and public key pairings and specifies how to sign an email in order to verify and confirm the legitimacy of a message emitted from your domain.
BIMI | Brand Indicator for Message Identification
BIMI associate a logo with an email domain and enable the display of a check mark next to your domain on webmail providers such as Gmail.
BIMI requires:
- DMARC
- a trademarked logo
- VMC, the certificate that verifies your identidy, domain and trademark.