SendGrid
Email is the backbone of your customer engagement. The Twilio SendGrid Email API is the email service trusted by developers and marketers for time-savings, scalability, and delivery expertise. Our flexible Email API and proprietary Mail Transfer Agent (MTA), intuitive console, powerful features, and email experts make it easy to ensure all your email gets delivered in seconds and without interruption. Monitor engagement data and optimize deliverability with our Deliverability Insights dashboard.
Whether you’re sending 100 emails or 100 billion, SendGrid is built to scale. Integrate with our RESTful APIs and SMTP in minutes, with sample code libraries available in 7 languages, interactive docs, templates, and more.
Learn more
SMTP Debug Tool
Ensure flawless email communication with the SMTP Debug Tool, a completely free and secure way to diagnose SMTP connection issues.
This tool connects to your SMTP server, initiates a test session, and provides a detailed log of the interaction between servers. Whether you're using popular email services like SendGrid, Google SMTP, Elastic Email, UniOne or Mailgun, this tool simplifies troubleshooting and helps resolve sending errors.
With end-to-end encryption, your information remains private and secure.
The tool doesn’t store any session logs or credentials, and you can further enhance security by changing your password after testing or using the optional “SMTP Blackhole” feature.
Learn more
Coldletter
Coldletter is an email templating and automation platform built for product and engineering teams that need better control over the emails their applications send. The platform works on top of providers such as SendGrid, Postmark, Amazon SES, Mailgun, Resend, and SparkPost, allowing teams to keep their existing delivery stack. Users can design responsive, accessible, and dark-mode-safe email templates with a visual editor instead of hand-coding complex HTML or MJML. Coldletter also supports reusable blocks, typed variables, live previews, test sends, localization, version control, and approval workflows. Its automation tools let teams build email journeys with triggers, waits, branches, A/B testing, and delivery analytics. Coldletter helps teams design, automate, manage, and deliver product emails more reliably from one centralized workspace.
Learn more
AcelleMail
AcelleMail is self-hosted email-marketing and marketing-automation software sold under a one-time license, with full PHP/Laravel source code included. You bring your own sending provider — Amazon SES, SendGrid, or any SMTP — so there are no per-contact or per-email fees. It supports unlimited lists and subscribers, campaign automation, autoresponders, segmentation, bounce and feedback-loop handling, detailed analytics, and multi-user/multi-account management. Ideal for agencies, developers, and businesses that want to run their own email infrastructure at a predictable cost.
Learn more