Postmark (ActiveCampaign): Complete Technical Guide to Transactional Email
Detailed technical guide for developers: DNS configuration (DKIM, custom Return-Path), REST API vs SMTP, Message Streams, dedicated IP, webhooks and 2026 pricing.
API
REST APIs, webhooks, and programmatic DNS management.
7 articles
January 2026
Mandrill (Mailchimp Transactional): Technical Guide for Transactional Email
A complete guide for developers and system admins: DKIM configuration via CNAME, choosing between API and SMTP, Mailchimp prerequisites, and pitfalls to avoid.
Mailgun: Complete Technical Guide for Transactional Email
A detailed technical guide for developers: DNS configuration (SPF, 2048-bit DKIM with autorotation), REST API vs SMTP, dedicated vs shared IP, limits and webhooks.
Amazon SES: Complete Guide to DNS Configuration and Email Authentication
Complete Amazon SES configuration with Easy DKIM, Custom MAIL FROM, strict DMARC alignment. Everything you need for optimal deliverability and GDPR compliance.
Mailjet: Complete Technical Guide for Transactional Email in 2026
A comprehensive guide for developers and system admins: DKIM configuration, API v3 vs v3.1, dedicated vs shared IP, and pitfalls to avoid with Mailjet.
Twilio SendGrid: Complete Technical Guide for Transactional Email
A detailed technical guide for developers: DNS configuration (SPF, 2048-bit DKIM), Web API v3, SMTP Relay, dedicated vs shared IP, limits and webhooks.
Brevo (formerly Sendinblue): Technical Guide for Transactional Emailing
A comprehensive guide for developers and sysadmins: DKIM configuration, choosing between API and SMTP, technical limits, and pitfalls to avoid with Brevo.